实现收发消息

本文将指导你如何利用 RTM Java SDK 构建简单的应用程序，内容涵盖了集成和开发的基础知识：开通声网账号、获取 SDK、发送消息、接收消息等。

同时，我们也提供了开源的示例项目供你参考，你可以前往下载或查看其中的源代码。

准备工作Copy Anchor Link

开始构建项目前，你需要完成开通 RTM 服务，并检查你的开发环境是否满足平台支持中的最低版本要求。

构建项目Copy Anchor Link

1. 项目配置Copy Anchor Link

根据以下步骤配置你的项目：

1. 在 Android Studio 里，创建一个 Empty Activity 类型的项目并打开。
2. 通过以下任意一种方式获取最新的 RTM Java SDK 并导入你的项目。

3. 添加网络权限。打开 app/src/main/AndroidManifest.xml 文件，在 <manifest> 的下一行添加如下代码：

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   <uses-permission android:name="android.permission.INTERNET" />
   <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

4. 在 /Gradle Scripts/proguard-rules.pro 文件中添加如下代码，以防止声网 SDK 的代码被混淆：

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   -keep class io.agora.**{*;}

2. 初始化 RTMCopy Anchor Link

调用 RTM SDK 的任何 API 之前，需要先初始化一个 RtmClient 对象实例。参考如下步骤创建用户界面、初始化一个 RtmClient 对象实例。

1. 创建用户界面。实时消息 App 一般会有如下输入框和按钮：

   • 用户名、频道名、消息输入框
   • 登录、登出按钮
   • 订阅、取消订阅频道按钮
   • 发送消息按钮

   本节提供简易的 UI 界面设计以便于验证功能特性，你可以根据实际项目需求进行修改。

   1. 打开 /app/res/layout/activity_main.xml 文件，将文件内容替换为如下代码：

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      <?xml version="1.0" encoding="utf-8"?>
      <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
          xmlns:app="http://schemas.android.com/apk/res-auto"
          xmlns:tools="http://schemas.android.com/tools"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:background="#FFFFFF"
          tools:context=".MainActivity">
      
          <EditText
              android:id="@+id/uid"
              android:layout_width="150dp"
              android:layout_height="40dp"
              android:layout_marginStart="36dp"
              android:layout_marginTop="48dp"
              android:autofillHints=""
              android:hint="@string/uid"
              android:inputType="text"
              android:lines="1"
              android:padding="5dp"
              app:layout_constraintStart_toStartOf="parent"
              app:layout_constraintTop_toTopOf="parent" />
      
          <Button
              android:id="@+id/logout_button"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:layout_marginStart="11dp"
              android:layout_marginTop="48dp"
              android:layout_marginEnd="28dp"
              android:onClick="onClickLogout"
              android:text="@string/logout_button"
              app:layout_constraintEnd_toEndOf="parent"
              app:layout_constraintHorizontal_bias="0.0"
              app:layout_constraintStart_toEndOf="@+id/login_button"
              app:layout_constraintTop_toTopOf="parent" />
      
          <Button
              android:id="@+id/login_button"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:layout_marginStart="4dp"
              android:layout_marginTop="48dp"
              android:layout_marginEnd="132dp"
              android:onClick="onClickLogin"
              android:text="@string/login_button"
              app:layout_constraintEnd_toEndOf="parent"
              app:layout_constraintHorizontal_bias="0.0"
              app:layout_constraintStart_toEndOf="@+id/uid"
              app:layout_constraintTop_toTopOf="parent" />
      
          <EditText
              android:id="@+id/channel_name"
              android:layout_width="155dp"
              android:layout_height="41dp"
              android:layout_marginStart="36dp"
              android:layout_marginTop="124dp"
              android:layout_marginBottom="41dp"
              android:autofillHints=""
              android:ems="10"
              android:hint="@string/channel_name"
              android:inputType="text"
              app:layout_constraintTop_toBottomOf="@+id/uid"
              app:layout_constraintStart_toStartOf="parent"
              app:layout_constraintTop_toTopOf="parent" />
      
          <Button
              android:id="@+id/subscribe_button"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:layout_marginStart="4dp"
              android:layout_marginTop="28dp"
              android:layout_marginEnd="132dp"
              android:onClick="onClickSubscribe"
              android:text="@string/subscribe_button"
              app:layout_constraintEnd_toEndOf="parent"
              app:layout_constraintHorizontal_bias="0.0"
              app:layout_constraintStart_toEndOf="@+id/channel_name"
              app:layout_constraintTop_toBottomOf="@+id/login_button" />
      
          <Button
              android:id="@+id/unsubscribe_button"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:layout_marginStart="11dp"
              android:layout_marginTop="27dp"
              android:layout_marginEnd="28dp"
              android:onClick="onClickUnsubscribe"
              android:text="@string/unsubscribe_button"
              app:layout_constraintEnd_toEndOf="parent"
              app:layout_constraintHorizontal_bias="0.0"
              app:layout_constraintStart_toEndOf="@+id/subscribe_button"
              app:layout_constraintTop_toBottomOf="@+id/logout_button" />
      
          <EditText
              android:id="@+id/msg_box"
              android:layout_width="190dp"
              android:layout_height="57dp"
              android:layout_marginStart="37dp"
              android:layout_marginTop="195dp"
              android:layout_marginBottom="26dp"
              android:autofillHints=""
              android:ems="10"
              android:hint="@string/msg"
              android:inputType="textPersonName"
              android:singleLine="false"
              app:layout_constraintTop_toTopOf="parent"
              app:layout_constraintStart_toStartOf="parent"
              app:layout_constraintTop_toBottomOf="@+id/channel_name" />
      
          <Button
              android:id="@+id/send_channel_msg_button"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:layout_marginTop="40dp"
              android:layout_marginEnd="40dp"
              android:onClick="onClickSendChannelMsg"
              android:text="@string/send_channel_msg_button"
              app:layout_constraintStart_toEndOf="@+id/msg_box"
              app:layout_constraintHorizontal_bias="0.0"
              app:layout_constraintEnd_toEndOf="parent"
              app:layout_constraintTop_toBottomOf="@+id/unsubscribe_button" />
      
          <TextView
              android:id="@+id/message_history"
              android:layout_width="412dp"
              android:layout_height="339dp"
              android:layout_marginTop="392dp"
              android:background="#AEA8A8"
              android:freezesText="false"
              android:isScrollContainer="false"
              android:scrollbars="vertical"
              android:textColor="#2196F3"
              app:layout_constraintBottom_toBottomOf="parent"
              app:layout_constraintEnd_toEndOf="parent"
              app:layout_constraintHorizontal_bias="0.491"
              app:layout_constraintStart_toStartOf="parent"
              app:layout_constraintTop_toTopOf="parent"
              app:layout_constraintVertical_bias="0.352" />
      
      </androidx.constraintlayout.widget.ConstraintLayout>

   2. 打开 app/res/values/strings.xml 文件，将文件内容替换为如下代码：

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      <resources>
          <string name="app_name">RtmQuickstart</string>
          <string name="login_button">Login</string>
          <string name="logout_button">Logout</string>
          <string name="subscribe_button">Sub</string>
          <string name="unsubscribe_button">Unsub</string>
          <string name="send_channel_msg_button">Publish MSG</string>
          <string name="uid">User ID</string>
          <string name="msg">Message content</string>
          <string name="channel_name">Channel name</string>
      
          <string name="app_id">your_appid</string>
          <string name="token">your_token</string>
      </resources>

      信息

      你需要将示例中的 your_appid 和 your_token 字段替换成你项目的 App ID 和 Token。在测试阶段，为快速验证功能，我们建议你在创建声网项目时将鉴权模式设置为调试模式，然后将示例中的 your_appid 和 your_token 字段都替换成你项目的 App ID。

2. 打开 app/src/main/java/com/example/rtm/MainActivity.java 文件，将文件内容替换为如下代码。你会发现此程序并不完整，不用紧张，我们在后续步骤中将一步步指导你补充完善代码。

   信息

   com.example.rtm 为示例项目的路径，你需要根据实际项目路径查找文件并填写代码。

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   // Replace the package path with the path of your real project.
   package com.example.rtm;
   
   import android.content.pm.ActivityInfo;
   import android.os.Bundle;
   import android.view.View;
   import android.widget.EditText;
   import android.widget.TextView;
   import android.widget.Toast;
   
   import androidx.appcompat.app.AppCompatActivity;
   
   import io.agora.rtm.ErrorInfo;
   import io.agora.rtm.LinkStateEvent;
   import io.agora.rtm.LockEvent;
   import io.agora.rtm.MessageEvent;
   import io.agora.rtm.PresenceEvent;
   import io.agora.rtm.PublishOptions;
   import io.agora.rtm.ResultCallback;
   import io.agora.rtm.RtmClient;
   import io.agora.rtm.RtmConfig;
   import io.agora.rtm.RtmConstants;
   import io.agora.rtm.RtmEventListener;
   import io.agora.rtm.RtmMessage;
   import io.agora.rtm.StorageEvent;
   import io.agora.rtm.SubscribeOptions;
   import io.agora.rtm.TopicEvent;
   
   
   public class MainActivity extends AppCompatActivity {
       private EditText etUserId;
       private EditText etChannelName;
       private EditText etMessageContent;
   
       // The user ID of the publisher
       private String mUserId;
       // The channel name of the message channel
       private String mChannelName;
   
       // The RTM client instance
       private RtmClient mRtmClient;
       // The TextView to show the messages that you send
       private TextView mMessageHistory;
   
       // Add the event listener
   
       @Override
       protected void onCreate(Bundle savedInstanceState) {
           super.onCreate(savedInstanceState);
           setContentView(R.layout.activity_main);
           setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
       }
   
       @Override
       protected void onResume() {
           super.onResume();
       }
   
       @Override
       protected void onDestroy() {
           super.onDestroy();
       }
   
       public void onClickLogin(View v)
       {
           try {
               etUserId = (EditText) findViewById(R.id.uid);
               mUserId = etUserId.getText().toString();
               if (mUserId == null || mUserId.isEmpty()) {
                   showToast("invalid userId");
                   return;
               }
               RtmConfig config = new RtmConfig.Builder(getBaseContext().getString(R.string.app_id), mUserId)
                         .eventListener(eventListener)
                         .build();
               mRtmClient = RtmClient.create(config);
           } catch (Exception e) {
               showToast("create rtm client is null");
           }
   
           if (mRtmClient == null) {
               showToast("rtm client is null");
               return;
           }
   
           // Log in the RTM server
       }
   
       public void onClickSubscribe(View v)
       {
           if (mRtmClient == null) {
               showToast("rtm client is null");
               return;
           }
   
           // Subscribe to a channel
       }
   
       public void onClickLogout(View v)
       {
           if (mRtmClient == null) {
               showToast("rtm client is null");
           }
           // Log out from the RTM server
       }
   
       public void onClickUnsubscribe(View v)
       {
           if (mRtmClient == null) {
               showToast("rtm client is null");
               return;
           }
           // Unsubscribe from a channel
       }
   
       public void onClickSendChannelMsg(View v)
       {
           // Publish a message
       }
   
       // Write message history to TextView
       public void writeToMessageHistory(String record)
       {
           mMessageHistory = findViewById(R.id.message_history);
           mMessageHistory.append(record);
       }
   
       private void showToast(String text) {
           Toast.makeText(this, text, Toast.LENGTH_SHORT).show();
       }
   }

如需了解更多初始化的信息，查看初始配置。

3. 添加事件监听Copy Anchor Link

事件监听程序帮助你实现频道中消息、事件到达后的处理逻辑，添加以下代码到你的程序中以显示收到的消息或事件通知：

// Paste the following code snippet below "Add the event listener" comment
private RtmEventListener eventListener = new RtmEventListener() {
    @Override
    public void onMessageEvent(MessageEvent event) {
        String text = "Message received from " + event.getPublisherId() + " Message: " + event.getMessage().getData() + "\n";
        writeToMessageHistory(text);
    }

    @Override
    public void onPresenceEvent(PresenceEvent event) {
        String text = "receive presence event, user: " + event.getPublisherId() + " event: " + event.getEventType() + "\n";
        writeToMessageHistory(text);
    }

    @Override
    public void onLinkStateEvent(LinkStateEvent event) {
        String text = "Link state event: " + event + "\n";
        writeToMessageHistory(text);
    }
};

4. 登录服务Copy Anchor Link

你需要执行登录操作才能建立与 RTM 服务器的连接，然后才能调用 SDK 的其他 API。将以下代码添加到程序中：

// Paste the following code snippet below "Log in the RTM server" comment
String token =getBaseContext().getString(R.string.token);
mRtmClient.login(token, new ResultCallback<Void>() {
    @Override
    public void onSuccess(Void responseInfo) {
        writeToMessageHistory("Successfully log in the RTM server!\n");
    }

    @Override
    public void onFailure(ErrorInfo errorInfo) {
        CharSequence text = "User: " + mUserId + " Fail to log in to the RTM system!" + errorInfo.toString();
        int duration = Toast.LENGTH_SHORT;
        runOnUiThread(new Runnable() {
            public void run() {
                Toast toast = Toast.makeText(getApplicationContext(), text, duration);
                toast.show();
            }
        });
    }
});

5. 收发消息Copy Anchor Link

调用 publish 方法向 Message Channel 发送消息后，RTM 会把该消息分发给该频道的所有订阅者，以下代码演示如何发送字符串类型的消息，将此代码片段添加到程序中：

// Paste the following code snippet below "Publish a message" comment
etMessageContent = findViewById(R.id.msg_box);
String message = etMessageContent.getText().toString();
etChannelName = (EditText) findViewById(R.id.channel_name);
mChannelName = etChannelName.getText().toString();
PublishOptions options = new PublishOptions();
options.setCustomType("");
mRtmClient.publish(mChannelName, message, options, new ResultCallback<Void>() {
    @Override
    public void onSuccess(Void responseInfo) {
        String text = "Message sent to channel " + mChannelName + " : " + message + "\n";
        writeToMessageHistory(text);
    }

    @Override
    public void onFailure(ErrorInfo errorInfo) {
        String text = "Message fails to send to channel " + mChannelName + " Error: " + errorInfo + "\n";
        writeToMessageHistory(text);
    }
});

调用 subscribe 方法订阅此频道以接收此频道中的消息。将以下代码添加到程序中：

// Paste the following code snippet below "Subscribe to a channel" comment
etChannelName = (EditText) findViewById(R.id.channel_name);
mChannelName = etChannelName.getText().toString();
SubscribeOptions options = new SubscribeOptions();
options.setWithMessage(true);
mRtmClient.subscribe(mChannelName, options, new ResultCallback<Void>() {
    @Override
    public void onSuccess(Void responseInfo) {
        writeToMessageHistory("Successfully subscribe to the channel!\n");
    }

    @Override
    public void onFailure(ErrorInfo errorInfo) {
        writeToMessageHistory("Fail to subscribe to the channel!\n");
    }
});

如果你不再需要在此频道收发消息，你可以调用 unsubscribe 方法取消订阅此频道。将以下代码添加到程序中：

// Paste the following code snippet below "Unsubscribe from a channel" comment
etChannelName = (EditText) findViewById(R.id.channel_name);
mChannelName = etChannelName.getText().toString();
mRtmClient.unsubscribe(mChannelName, new ResultCallback<Void>() {
    @Override
    public void onSuccess(Void responseInfo) {
        writeToMessageHistory("Successfully unsubscribe from the channel!\n");
    }

    @Override
    public void onFailure(ErrorInfo errorInfo) {
        writeToMessageHistory("Fail to unsubscribe from the channel!\n");
    }
});

如需了解更多收发消息的信息，查看消息。

6. 登出服务Copy Anchor Link

当不再需要使用 RTM 服务时，你可以调用 logout 方法登出 RTM 系统。将以下代码添加到程序中：

// Paste the following code snippet below "Log out from the RTM server" comment
mRtmClient.logout(new ResultCallback<Void>() {
    @Override
    public void onSuccess(Void responseInfo) {
        writeToMessageHistory("Successfully log out from the channel!\n");
    }

    @Override
    public void onFailure(ErrorInfo errorInfo) {
        writeToMessageHistory("Fail to log out from the channel!\n");
    }
});

7. 组合到一起Copy Anchor Link

经过上述步骤，你程序中的代码应该如下所示：

  // Replace the package path with the path of your real project.
  package com.example.rtm;

  import android.content.pm.ActivityInfo;
  import android.os.Bundle;
  import android.view.View;
  import android.widget.EditText;
  import android.widget.TextView;
  import android.widget.Toast;

  import androidx.appcompat.app.AppCompatActivity;

  import io.agora.rtm.ErrorInfo;
  import io.agora.rtm.LinkStateEvent;
  import io.agora.rtm.LockEvent;
  import io.agora.rtm.MessageEvent;
  import io.agora.rtm.PresenceEvent;
  import io.agora.rtm.PublishOptions;
  import io.agora.rtm.ResultCallback;
  import io.agora.rtm.RtmClient;
  import io.agora.rtm.RtmConfig;
  import io.agora.rtm.RtmConstants;
  import io.agora.rtm.RtmEventListener;
  import io.agora.rtm.RtmMessage;
  import io.agora.rtm.StorageEvent;
  import io.agora.rtm.SubscribeOptions;
  import io.agora.rtm.TopicEvent;


  public class MainActivity extends AppCompatActivity {
      private EditText etUserId;
      private EditText etChannelName;
      private EditText etMessageContent;

      // The user ID of the publisher
      private String mUserId;
      // The channel name of the message channel
      private String mChannelName;

      // The RTM client instance
      private RtmClient mRtmClient;
      // The TextView to show the messages that you send
      private TextView mMessageHistory;

      // Add the event listener
      private RtmEventListener eventListener = new RtmEventListener() {
          @Override
          public void onMessageEvent(MessageEvent event) {
              String text = "Message received from " + event.getPublisherId() + " Message: " + event.getMessage().getData() + "\n";
              writeToMessageHistory(text);
          }

          @Override
          public void onPresenceEvent(PresenceEvent event) {
              String text = "receive presence event, user: " + event.getPublisherId() + " event: " + event.getEventType() + "\n";
              writeToMessageHistory(text);
          }

          @Override
          public void onLinkStateEvent(LinkStateEvent event) {
              String text = "Link state event: " + event + "\n";
              writeToMessageHistory(text);
          }
      };

      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
          setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
      }

      @Override
      protected void onResume() {
          super.onResume();
      }

      @Override
      protected void onDestroy() {
          super.onDestroy();
      }

      public void onClickLogin(View v)
      {
          try {
              etUserId = (EditText) findViewById(R.id.uid);
              mUserId = etUserId.getText().toString();
              if (mUserId == null || mUserId.isEmpty()) {
                  showToast("invalid userId");
                  return;
              }
              RtmConfig config = new RtmConfig.Builder(getBaseContext().getString(R.string.app_id), mUserId)
                  .eventListener(eventListener)
                  .build();
              mRtmClient = RtmClient.create(config);
          } catch (Exception e) {
              showToast("create rtm client is null");
          }

          if (mRtmClient == null) {
              showToast("rtm client is null");
              return;
          }

          // Log in the RTM server
          String token =getBaseContext().getString(R.string.token);
          mRtmClient.login(token, new ResultCallback<Void>() {
              @Override
              public void onSuccess(Void responseInfo) {
                  writeToMessageHistory("Successfully log in the RTM server!\n");
              }

              @Override
              public void onFailure(ErrorInfo errorInfo) {
                  CharSequence text = "User: " + mUserId + " Fail to log in to the RTM system!" + errorInfo.toString();
                  int duration = Toast.LENGTH_SHORT;
                  runOnUiThread(new Runnable() {
                      public void run() {
                          Toast toast = Toast.makeText(getApplicationContext(), text, duration);
                          toast.show();
                      }
                  });
              }
          });
      }

      public void onClickSubscribe(View v)
      {
          if (mRtmClient == null) {
              showToast("rtm client is null");
              return;
          }

          // Subscribe to a channel
          etChannelName = (EditText) findViewById(R.id.channel_name);
          mChannelName = etChannelName.getText().toString();

          SubscribeOptions options = new SubscribeOptions();
          options.setWithMessage(true);
          mRtmClient.subscribe(mChannelName, options, new ResultCallback<Void>() {
              @Override
              public void onSuccess(Void responseInfo) {
                  writeToMessageHistory("Successfully subscribe to the channel!\n");
              }

              @Override
              public void onFailure(ErrorInfo errorInfo) {
                  writeToMessageHistory("Fail to subscribe to the channel!\n");
              }
          });
      }

      public void onClickLogout(View v)
      {
          if (mRtmClient == null) {
              showToast("rtm client is null");
          }
          // Log out from the RTM server
          mRtmClient.logout(new ResultCallback<Void>() {
              @Override
              public void onSuccess(Void responseInfo) {
                  writeToMessageHistory("Successfully log out from the channel!\n");
              }

              @Override
              public void onFailure(ErrorInfo errorInfo) {
                  writeToMessageHistory("Fail to log out from the channel!\n");
              }
          });
      }

      public void onClickUnsubscribe(View v)
      {
          if (mRtmClient == null) {
              showToast("rtm client is null");
              return;
          }
          // Unsubscribe from a channel
          etChannelName = (EditText) findViewById(R.id.channel_name);
          mChannelName = etChannelName.getText().toString();
          mRtmClient.unsubscribe(mChannelName, new ResultCallback<Void>() {
              @Override
              public void onSuccess(Void responseInfo) {
                  writeToMessageHistory("Successfully unsubscribe from the channel!\n");
              }

              @Override
              public void onFailure(ErrorInfo errorInfo) {
                  writeToMessageHistory("Fail to unsubscribe from the channel!\n");
              }
          });
      }

      public void onClickSendChannelMsg(View v)
      {
          etMessageContent = findViewById(R.id.msg_box);
          String message = etMessageContent.getText().toString();

          // Publish a message
          etChannelName = (EditText) findViewById(R.id.channel_name);
          mChannelName = etChannelName.getText().toString();
          PublishOptions options = new PublishOptions();
          options.setCustomType("");
          mRtmClient.publish(mChannelName, message, options, new ResultCallback<Void>() {
              @Override
              public void onSuccess(Void responseInfo) {
                  String text = "Message sent to channel " + mChannelName + " : " + message + "\n";
                  writeToMessageHistory(text);
              }

              @Override
              public void onFailure(ErrorInfo errorInfo) {
                  String text = "Message fails to send to channel " + mChannelName + " Error: " + errorInfo + "\n";
                  writeToMessageHistory(text);
              }
          });
      }

      // Write message history to TextView
      public void writeToMessageHistory(String record)
      {
          mMessageHistory = findViewById(R.id.message_history);
          mMessageHistory.append(record);
      }

      private void showToast(String text) {
          Toast.makeText(this, text, Toast.LENGTH_SHORT).show();
      }
  }

现在，你可以开始运行你的程序：

1. 保存项目。
2. 在菜单栏中依次点击 Run > Select Device > Select Multiple Devices 并添加两个设备。例如，选择一个虚拟机和一个真机。
3. 运行项目。成功运行后，你可以在两个设备中看到 App 界面。
4. 将一个设备作为接收端，进行如下操作：
   1. 输入用户名，点击 LOGIN。
   2. 输入频道名，点击 SUB。
5. 将另一个设备作为发送端，进行如下操作：
   1. 输入不同的用户名，点击 LOGIN。
   2. 输入相同的频道名。
   3. 输入消息，点击 PUBLISH MSG。
6. 将上面的发送端和设备端互换，重复步骤 4 和 5。

如果两个设备均可收发消息，那么你已经成功集成并正确使用了 RTM 服务。

贯穿始终Copy Anchor Link

相比于介绍如何写出代码，声网更愿意帮助你掌握上述程序编写的过程和逻辑。上述程序依次完成了以下操作，让你可以正确地收发消息：

1. 设置并初始化 RTM 对象。
2. 添加 onMessageEvent、onPresenceEvent 和 onLinkStateEvent 事件监听函数。
3. 调用 login 登录了 RTM 服务。
4. 调用 subscribe 订阅了一个 Message Channel。
5. 调用 publish 发送消息。
6. 调用 unsubscribe 取消订阅一个 Message Channel。
7. 调用 logout 登出 RTM 系统。

下一步Copy Anchor Link

现在，你已经学会了如何使用 RTM Java SDK 来实现 Message Channel 的收发消息功能。下一步，你可以通过 SDK 的 API 参考了解更多功能的使用方法。

本文将指导你如何利用 RTM Objective-C SDK 构建简单的应用程序，内容涵盖了集成和开发的基础知识：开通声网账号、获取 SDK、发送消息、接收消息等。

准备工作Copy Anchor Link

开始构建项目前，你需要完成开通 RTM 服务，并检查你的开发环境是否满足平台支持中的最低版本要求。

构建项目Copy Anchor Link

1. 项目配置Copy Anchor Link

根据以下步骤配置你的项目：

1. 在 Xcode 中创建一个 iOS 平台下的 Single View App，项目设置如下：
   • Product Name 设为 RtmQuickstart。
   • Organization Identifier 设为 agora。
   • User Interface 选择 Storyboard。
   • Language 选择 Objective-C。
2. 通过以下任意一种方式获取最新的 RTM Objective-C SDK 并导入你的项目。

https://github.com/AgoraIO/AgoraRtm_Apple.git

2. 初始化 RTMCopy Anchor Link

调用 RTM SDK 的任何 API 之前，需要先初始化一个 AgoraRtmClientKit 对象实例。参考如下步骤创建用户界面、初始化一个 AgoraRtmClientKit 对象实例。

1. 创建用户界面。实时消息 App 一般会有如下输入框和按钮：

   • 用户名、频道名、消息输入框
   • 登录、登出按钮
   • 订阅、取消订阅频道按钮
   • 发送消息按钮

   本节提供简易的 UI 界面设计以便于验证功能特性，你可以根据实际项目需求进行修改。

   1. 使用 Code View 打开 Main.storyboard 并将文件内容替换为以下代码：

      Copy Text

      <?xml version="1.0" encoding="UTF-8"?>
      <document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="21701" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES" initialViewController="BYZ-38-t0r">
          <device id="retina6_1" orientation="portrait" appearance="light"/>
          <dependencies>
              <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="21679"/>
              <capability name="Safe area layout guides" minToolsVersion="9.0"/>
              <capability name="System colors in document resources" minToolsVersion="11.0"/>
              <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
          </dependencies>
          <scenes>
              <!--View Controller-->
              <scene sceneID="tne-QT-ifu">
                  <objects>
                      <viewController id="BYZ-38-t0r" customClass="ViewController" sceneMemberID="viewController">
                          <view key="view" contentMode="scaleToFill" id="8bC-Xf-vdC">
                              <rect key="frame" x="0.0" y="0.0" width="414" height="896"/>
                              <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                              <subviews>
                                  <button opaque="NO" contentMode="scaleToFill" fixedFrame="YES" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="M2K-rz-dlO">
                                      <rect key="frame" x="254" y="103" width="38" height="30"/>
                                      <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
                                      <state key="normal" title="Login"/>
                                      <connections>
                                          <action selector="Login:" destination="BYZ-38-t0r" eventType="touchUpInside" id="UEU-up-ksL"/>
                                      </connections>
                                  </button>
                                  <button opaque="NO" contentMode="scaleToFill" fixedFrame="YES" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="CZ1-G5-AkG">
                                      <rect key="frame" x="326" y="103" width="48" height="30"/>
                                      <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
                                      <state key="normal" title="Logout"/>
                                      <connections>
                                          <action selector="Logout:" destination="BYZ-38-t0r" eventType="touchUpInside" id="a0d-8h-eyX"/>
                                      </connections>
                                  </button>
                                  <button opaque="NO" contentMode="scaleToFill" fixedFrame="YES" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="0px-1e-aMC">
                                      <rect key="frame" x="242" y="172" width="62" height="30"/>
                                      <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
                                      <state key="normal" title="Subscribe"/>
                                      <connections>
                                          <action selector="SubscribeChannel:" destination="BYZ-38-t0r" eventType="touchUpInside" id="12c-US-VQk"/>
                                      </connections>
                                  </button>
                                  <button opaque="NO" contentMode="scaleToFill" fixedFrame="YES" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="SDQ-Zt-rBD">
                                      <rect key="frame" x="307" y="172" width="87" height="30"/>
                                      <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
                                      <state key="normal" title="Unsubscribe"/>
                                      <connections>
                                          <action selector="UnsubscribeChannel:" destination="BYZ-38-t0r" eventType="touchUpInside" id="u4T-ze-wtj"/>
                                      </connections>
                                  </button>
                                  <textField opaque="NO" contentMode="scaleToFill" fixedFrame="YES" contentHorizontalAlignment="left" contentVerticalAlignment="center" text="User ID" borderStyle="roundedRect" textAlignment="natural" minimumFontSize="17" translatesAutoresizingMaskIntoConstraints="NO" id="69v-UU-ObH">
                                      <rect key="frame" x="40" y="99" width="187" height="34"/>
                                      <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
                                      <fontDescription key="fontDescription" type="system" pointSize="14"/>
                                      <textInputTraits key="textInputTraits"/>
                                  </textField>
                                  <textField opaque="NO" contentMode="scaleToFill" fixedFrame="YES" contentHorizontalAlignment="left" contentVerticalAlignment="center" text="Channel name" borderStyle="roundedRect" textAlignment="natural" minimumFontSize="17" translatesAutoresizingMaskIntoConstraints="NO" id="dGk-g2-qHK">
                                      <rect key="frame" x="40" y="168" width="187" height="34"/>
                                      <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
                                      <fontDescription key="fontDescription" type="system" pointSize="14"/>
                                      <textInputTraits key="textInputTraits"/>
                                  </textField>
                                  <button opaque="NO" contentMode="scaleToFill" fixedFrame="YES" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="Qqk-6X-Tcb">
                                      <rect key="frame" x="304" y="247" width="88" height="30"/>
                                      <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
                                      <state key="normal" title="Publish MSG"/>
                                      <connections>
                                          <action selector="SendMessageToMessageChannel:" destination="BYZ-38-t0r" eventType="touchUpInside" id="XcX-nz-fPl"/>
                                      </connections>
                                  </button>
                                  <textField opaque="NO" contentMode="scaleToFill" fixedFrame="YES" contentHorizontalAlignment="left" contentVerticalAlignment="center" text="Message content" borderStyle="roundedRect" textAlignment="natural" minimumFontSize="17" translatesAutoresizingMaskIntoConstraints="NO" id="lKg-ap-M6p">
                                      <rect key="frame" x="40" y="245" width="252" height="34"/>
                                      <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
                                      <fontDescription key="fontDescription" type="system" pointSize="14"/>
                                      <textInputTraits key="textInputTraits"/>
                                  </textField>
                                  <textView clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="scaleToFill" fixedFrame="YES" textAlignment="natural" translatesAutoresizingMaskIntoConstraints="NO" id="e1v-i8-spC">
                                      <rect key="frame" x="40" y="416" width="330" height="428"/>
                                      <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
                                      <color key="backgroundColor" systemColor="systemBackgroundColor"/>
                                      <color key="textColor" systemColor="labelColor"/>
                                      <fontDescription key="fontDescription" type="system" pointSize="14"/>
                                      <textInputTraits key="textInputTraits" autocapitalizationType="sentences"/>
                                  </textView>
                              </subviews>
                              <viewLayoutGuide key="safeArea" id="6Tk-OE-BBY"/>
                              <color key="backgroundColor" systemColor="systemBackgroundColor"/>
                          </view>
                          <connections>
                              <outlet property="ChannelIDTextField" destination="dGk-g2-qHK" id="Iuh-ow-1MH"/>
                              <outlet property="GroupMsgButton" destination="Qqk-6X-Tcb" id="TV4-sg-bY7"/>
                              <outlet property="GroupMsgTextField" destination="lKg-ap-M6p" id="2Me-Z0-QIH"/>
                              <outlet property="LoginButton" destination="M2K-rz-dlO" id="ZxJ-oV-UKy"/>
                              <outlet property="LogoutButton" destination="CZ1-G5-AkG" id="ZQE-B7-yya"/>
                              <outlet property="MsgTextView" destination="e1v-i8-spC" id="76J-8Q-kKp"/>
                              <outlet property="SubsctibeButton" destination="0px-1e-aMC" id="9TL-8M-l6w"/>
                              <outlet property="UnSubscribeButton" destination="SDQ-Zt-rBD" id="tgd-fK-EfO"/>
                              <outlet property="UserIDTextField" destination="69v-UU-ObH" id="3BH-ci-t7A"/>
                          </connections>
                      </viewController>
                      <placeholder placeholderIdentifier="IBFirstResponder" id="dkx-z0-nzr" sceneMemberID="firstResponder"/>
                  </objects>
                  <point key="canvasLocation" x="131.8840579710145" y="97.767857142857139"/>
              </scene>
          </scenes>
          <resources>
              <systemColor name="labelColor">
                  <color red="0.0" green="0.0" blue="0.0" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
              </systemColor>
              <systemColor name="systemBackgroundColor">
                  <color white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
              </systemColor>
          </resources>
      </document>

   2. 打开 ViewController.h 文件，将文件内容替换为如下代码：

      Copy Text

      #import <UIKit/UIKit.h>
      
      #import <AgoraRtmKit/AgoraRtmKit.h>
      
      @interface ViewController : UIViewController
      
      // Buttons
      @property (weak, nonatomic) IBOutlet UIButton *LoginButton;
      @property (weak, nonatomic) IBOutlet UIButton *LogoutButton;
      @property (weak, nonatomic) IBOutlet UIButton *SubsctibeButton;
      @property (weak, nonatomic) IBOutlet UIButton *UnSubscribeButton;
      @property (weak, nonatomic) IBOutlet UIButton *GroupMsgButton;
      
      // Textfields
      @property (weak, nonatomic) IBOutlet UITextField *UserIDTextField;
      @property (weak, nonatomic) IBOutlet UITextField *ChannelIDTextField;
      @property (weak, nonatomic) IBOutlet UITextField *GroupMsgTextField;
      
      @property (weak, nonatomic) IBOutlet UITextView *MsgTextView;
      
      @end

2. 打开 ViewController.m 文件，将文件内容替换为如下代码。你会发现此程序并不完整，不用紧张，我们在后续步骤中将一步步指导你补充完善代码。

   信息

   你需要将示例中的 your_appid 和 your_token 字段替换成你项目的 App ID 和 Token。在测试阶段，为快速验证功能，我们建议你在创建声网项目时将鉴权模式设置为调试模式，然后将示例中的 your_appid 和 your_token 字段都替换成你项目的 App ID。

   Copy Text

   #import "ViewController.h"
   
   @interface ViewController ()<AgoraRtmClientDelegate>
   
   @property(nonatomic, strong)AgoraRtmClientKit* kit;
   
   @property NSString* appID;
   @property NSString* token;
   
   @property NSString* uid;
   @property NSString* peerID;
   @property NSString* channelID;
   @property NSString* peerMsg;
   @property NSString* channelMsg;
   
   @property NSString* text;
   @property NSMutableArray* textArray;
   
   - (void)AddMsgToRecord:(NSString*)text;
   
   @end
   
   @implementation ViewController
   
   - (void)viewDidLoad {
   [super viewDidLoad];
   // Enter your App ID
   self.appID = @"your_appid";
   self.MsgTextView.textColor = UIColor.blueColor;
   self.textArray = [[NSMutableArray alloc]init];
   }
   
   // Add the event listener
   
   // Add message to the UI TextView
   - (void)AddMsgToRecord:(NSString*)text {
   
   
   [self.textArray addObject:(self.text)];
   self.MsgTextView.text = [self.textArray componentsJoinedByString:(@"\n")];
   
   }
   
   - (IBAction)Login:(id)sender {
       self.uid = self.UserIDTextField.text;
       // Enter your token
       self.token = @"your_token";
   
       AgoraRtmClientConfig*  rtm_config = [[AgoraRtmClientConfig alloc] initWithAppId:_appID userId:_uid];
   
       NSError* initError = nil;
       _kit = [[AgoraRtmClientKit alloc] initWithConfig:rtm_config delegate:self error:&initError];
       if (initError != nil) {
           self.text = [NSString stringWithFormat:@"init error %@",initError];
           NSLog(@"%@", self.text);
           [self AddMsgToRecord:(self.text)];
       }
       // Log in the RTM server
   }
   
   - (IBAction)Logout:(id)sender {
   if (_kit != nil) {
       // Log out from the RTM server
       }
   }
   
   - (IBAction)SubscribeChannel:(id)sender {
   self.channelID = self.ChannelIDTextField.text;
   if (_kit != nil) {
       // Subscribe to a channel
       }
   }
   
   - (IBAction)UnsubscribeChannel:(id)sender {
       if (_kit == nil)
           return;
       // Unsubscribe from a channel
   }
   
   - (IBAction)SendMessageToMessageChannel:(id)sender {
   self.channelID = self.ChannelIDTextField.text;
   self.channelMsg = self.GroupMsgTextField.text;
       // Publish a message
   }
   @end

如需了解更多初始化的信息，查看初始配置。

3. 添加事件监听Copy Anchor Link

事件监听程序帮助你实现频道中消息、事件到达后的处理逻辑，添加以下代码到你的程序中以显示收到的消息或事件通知：

// Paste the following code snippet below "Add the event listener" comment
- (void)rtmKit:(AgoraRtmClientKit *)rtmKit didReceiveMessageEvent:(AgoraRtmMessageEvent *)event {
    NSLog(@"%@", self.text);
    self.text = [NSString stringWithFormat:@"receive message\nFrom channel: %@\npublisher:%@\nmessage:%@\n",event.channelName,event.publisher, event.message.stringData];
    [self AddMsgToRecord:(self.text)];
}

4. 登录服务Copy Anchor Link

你需要执行登录操作才能建立与 RTM 服务器的连接，然后才能调用 SDK 的其他 API。将以下代码添加到程序中：

// Paste the following code snippet below "Log in the RTM server" comment
[_kit loginByToken:self.token completion:^(AgoraRtmCommonResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if (errorInfo.errorCode != AgoraRtmErrorOk){
        self.text = [NSString stringWithFormat:@"Login failed for user %@. Code: %ld",self.uid, (long)errorInfo.errorCode];
        NSLog(@"%@", self.text);
    } else {
        NSLog(@"%@", self.text);
        self.text = [NSString stringWithFormat:@"Login successful for user %@. Code: %ld",self.uid, (long)errorInfo.errorCode];
    }
    [self AddMsgToRecord:(self.text)];
}];

5. 收发消息Copy Anchor Link

调用 publish 方法向 Message Channel 发送消息后，RTM 会把该消息分发给该频道的所有订阅者，以下代码演示如何发送字符串类型的消息，将此代码片段添加到程序中：

// Paste the following code snippet below "Publish a message" comment
[_kit publish:self.channelID message:self.channelMsg option:nil completion:^(AgoraRtmCommonResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if (errorInfo == nil) {
        self.text = [NSString stringWithFormat:@"Message sent to channel %@ : %@", self.channelID, self.channelMsg];
    } else {
        self.text = [NSString stringWithFormat:@"Message failed to send to channel %@ : %@ ErrorCode: %ld", self.channelID, self.channelMsg, (long)errorInfo.errorCode];
    }

    [self AddMsgToRecord:(self.text)];
}];

调用 subscribeWithChannel 方法订阅此频道以接收此频道中的消息。将以下代码添加到程序中：

// Paste the following code snippet below "Subscribe to a channel" comment
[_kit subscribeWithChannel:self.channelID option:nil completion:^(AgoraRtmCommonResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if(errorInfo == nil) {
        self.text = [NSString stringWithFormat:@"Successfully subscribe channel %@",self.channelID];
        NSLog(@"%@", self.text);
    } else {
        self.text = [NSString stringWithFormat:@"Failed to subscribe channel %@ Code: %ld",self.channelID, (long)errorInfo.errorCode];
        NSLog(@"%@", self.text);
    }

    [self AddMsgToRecord:(self.text)];
}];

如果你不再需要在此频道收发消息，你可以调用 unsubscribeWithChannel 方法取消订阅此频道。将以下代码添加到程序中：

// Paste the following code snippet below "Unsubscribe from a channel" comment
[_kit unsubscribeWithChannel:self.channelID completion:^(AgoraRtmCommonResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if (errorInfo == nil){
        self.text = [NSString stringWithFormat:@"Leave channel successful"];
    } else {
        self.text = [NSString stringWithFormat:@"Failed to leave channel Code: %ld", (long)errorInfo.errorCode];
    }

    [self AddMsgToRecord:(self.text)];
}];

如需了解更多收发消息的信息，查看消息。

6. 登出服务Copy Anchor Link

当不再需要使用 RTM 服务时，你可以调用 logout 方法登出 RTM 系统。将以下代码添加到程序中：

// Paste the following code snippet below "Log out from the RTM server" comment
[_kit logout:^(AgoraRtmCommonResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if (errorInfo == nil){
        self.text = [NSString stringWithFormat:@"Logout successful"];
        NSLog(@"%@", self.text);
        [_kit destroy];
        _kit = nil;
    } else {
        self.text = [NSString stringWithFormat:@"Logout failed. Code: %ld",(long)errorInfo.errorCode];
        NSLog(@"%@", self.text);
    }

    [self AddMsgToRecord:(self.text)];
}];

7. 组合到一起Copy Anchor Link

经过上述步骤，你程序中的代码应该如下所示：

#import "ViewController.h"

@interface ViewController ()<AgoraRtmClientDelegate>

@property(nonatomic, strong)AgoraRtmClientKit* kit;

@property NSString* appID;
@property NSString* token;

@property NSString* uid;
@property NSString* peerID;
@property NSString* channelID;
@property NSString* peerMsg;
@property NSString* channelMsg;

@property NSString* text;
@property NSMutableArray* textArray;

- (void)AddMsgToRecord:(NSString*)text;

@end

@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];
// Enter your App ID
self.appID = @"your_appid";
self.MsgTextView.textColor = UIColor.blueColor;
self.textArray = [[NSMutableArray alloc]init];
}

- (void)rtmKit:(AgoraRtmClientKit *)rtmKit didReceiveMessageEvent:(AgoraRtmMessageEvent *)event {
    NSLog(@"%@", self.text);
    self.text = [NSString stringWithFormat:@"receive message\nFrom channel: %@\npublisher:%@\nmessage:%@\n",event.channelName,event.publisher, event.message.stringData];
    [self AddMsgToRecord:(self.text)];
}

// Add message to the UI TextView
- (void)AddMsgToRecord:(NSString*)text {


[self.textArray addObject:(self.text)];
self.MsgTextView.text = [self.textArray componentsJoinedByString:(@"\n")];

}

- (IBAction)Login:(id)sender {
    self.uid = self.UserIDTextField.text;
    // Enter your token
    self.token = @"your_token";

    AgoraRtmClientConfig*  rtm_config = [[AgoraRtmClientConfig alloc] initWithAppId:_appID userId:_uid];

    NSError* initError = nil;
    _kit = [[AgoraRtmClientKit alloc] initWithConfig:rtm_config delegate:self error:&initError];
    if (initError != nil) {
        self.text = [NSString stringWithFormat:@"init error %@",initError];
        NSLog(@"%@", self.text);
        [self AddMsgToRecord:(self.text)];
    }
    // Log in the RTM server
    [_kit loginByToken:self.token completion:^(AgoraRtmCommonResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
        if (errorInfo.errorCode != AgoraRtmErrorOk){
            self.text = [NSString stringWithFormat:@"Login failed for user %@. Code: %ld",self.uid, (long)errorInfo.errorCode];
            NSLog(@"%@", self.text);
        } else {
            NSLog(@"%@", self.text);
            self.text = [NSString stringWithFormat:@"Login successful for user %@. Code: %ld",self.uid, (long)errorInfo.errorCode];
        }
        [self AddMsgToRecord:(self.text)];
    }];

}

- (IBAction)Logout:(id)sender {
if (_kit != nil) {
    // Log out from the RTM server
    [_kit logout:^(AgoraRtmCommonResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
        if (errorInfo == nil){
            self.text = [NSString stringWithFormat:@"Logout successful"];
            NSLog(@"%@", self.text);
            [_kit destroy];
            _kit = nil;
        } else {
            self.text = [NSString stringWithFormat:@"Logout failed. Code: %ld",(long)errorInfo.errorCode];
            NSLog(@"%@", self.text);
        }

        [self AddMsgToRecord:(self.text)];
    }];
}

- (IBAction)SubscribeChannel:(id)sender {
self.channelID = self.ChannelIDTextField.text;
if (_kit != nil) {
    // Subscribe to a channel
    [_kit subscribeWithChannel:self.channelID option:nil completion:^(AgoraRtmCommonResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
        if(errorInfo == nil) {
            self.text = [NSString stringWithFormat:@"Successfully subscribe channel %@",self.channelID];
            NSLog(@"%@", self.text);
        } else {
            self.text = [NSString stringWithFormat:@"Failed to subscribe channel %@ Code: %ld",self.channelID, (long)errorInfo.errorCode];
            NSLog(@"%@", self.text);
        }

        [self AddMsgToRecord:(self.text)];
    }];
    }
}

- (IBAction)UnsubscribeChannel:(id)sender {
    if (_kit == nil)
        return;
    // Unsubscribe from a channel
    [_kit unsubscribeWithChannel:self.channelID completion:^(AgoraRtmCommonResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
        if (errorInfo == nil){
            self.text = [NSString stringWithFormat:@"Leave channel successful"];
        } else {
            self.text = [NSString stringWithFormat:@"Failed to leave channel Code: %ld", (long)errorInfo.errorCode]; }

        [self AddMsgToRecord:(self.text)];
    }];
}

- (IBAction)SendMessageToMessageChannel:(id)sender {
self.channelID = self.ChannelIDTextField.text;
self.channelMsg = self.GroupMsgTextField.text;
    // Publish a message
    [_kit publish:self.channelID message:self.channelMsg option:nil completion:^(AgoraRtmCommonResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
        if (errorInfo == nil)
        {
            self.text = [NSString stringWithFormat:@"Message sent to channel %@ : %@", self.channelID, self.channelMsg];        }
        else
        {
            self.text = [NSString stringWithFormat:@"Message failed to send to channel %@ : %@ ErrorCode: %ld", self.channelID, self.channelMsg, (long)errorInfo.errorCode];        }

        [self AddMsgToRecord:(self.text)];
    }];
}
@end

现在，你可以开始运行你的程序：

1. 保存项目。
2. 复制当前项目，使用相同的 appId 和不同的 userId。
3. 运行上面的两个项目。成功运行后，你可以在两个设备中看到 App 界面。
4. 将一个设备作为接收端，进行如下操作：
   1. 输入用户名，点击 Login。
   2. 输入频道名，点击 Subscribe。
5. 将另一个设备作为发送端，进行如下操作：
   1. 输入不同的用户名，点击 Subscribe。
   2. 输入相同的频道名。
   3. 输入消息，点击 Publish MSG。
6. 将上面的发送端和设备端互换，重复步骤 4 和 5。

如果两个设备均可收发消息，那么你已经成功集成并正确使用了 RTM 服务。

贯穿始终Copy Anchor Link

相比于介绍如何写出代码，声网更愿意帮助你掌握上述程序编写的过程和逻辑。上述程序依次完成了以下操作，让你可以正确地收发消息：

1. 设置并初始化 RTM 对象。
2. 添加 didReceiveMessageEvent 事件监听函数。
3. 调用 loginByToken 登录了 RTM 服务。
4. 调用 subscribeWithChannel 订阅了一个 Message Channel。
5. 调用 publish 发送消息。
6. 调用 unsubscribeWithChannel 取消订阅一个 Message Channel。
7. 调用 logout 登出 RTM 系统。

下一步Copy Anchor Link

现在，你已经学会了如何使用 RTM Objective-C SDK 来实现 Message Channel 的收发消息功能。下一步，你可以通过 SDK 的 API 参考了解更多功能的使用方法。

本文将指导你如何利用 RTM JavaScript SDK 构建简单的应用程序，内容涵盖了集成和开发的基础知识：开通声网账号、获取 SDK、发送消息、接收消息等。

准备工作Copy Anchor Link

开始构建项目前，你需要完成开通 RTM 服务，并检查你的浏览器是否满足平台支持中的最低版本要求。

获取 SDKCopy Anchor Link

你可以通过以下任意一种方式获取最新的 RTM JavaScript SDK。

方式一：使用 CDN 添加 SDKCopy Anchor Link

点击此处下载最新版本的 JavaScript SDK，并在你的项目中添加以下代码引用它：

// 使用 CDN 直接将以下代码添加到你的 Web 应用中，或下载 SDK 文件后在本地引用
// 将 x.y.z 替换为具体的 SDK 版本号，如 2.3.0
// 可通过发版说明获取最新版本号
<script src="your_path_to_sdk/agora-rtm.x.y.z.min.js"></script>

方式二：使用包管理器引入 SDKCopy Anchor Link

1. 根据你的应用场景和开发需要，选择一种方式和工具安装 SDK。

   场景一：项目仅使用 RTM 产品，且没有集成声网任何版本的 RTC 产品。

   使用 npm使用 pnpm使用 Yarn

   Copy Text

   npm install agora-rtm

   Copy Text

   pnpm add agora-rtm

   Copy Text

   yarn add agora-rtm
   yarn add agora-rtc-sdk-ng@4.22.0 --save-exact

   场景二：项目中已经集成了 RTC 产品，需要新接入 RTM 产品。

   使用 npm使用 pnpm使用 Yarn

   Copy Text

   npm install agora-rtm

   Copy Text

   pnpm add agora-rtm

   如果项目使用的 RTC 版本与 RTM 中依赖的 RTC 版本不一致，会收到提示：unmet peer agora-rtc-sdk-ng@4.22.0: found 4.16.0。此时你需要升级 RTC 的版本：

   Copy Text

   pnpm update agora-rtc-sdk-ng@4.22.0

   或者通过以下命令同时保留两个版本的 RTC 库：

   Copy Text

   pnpm add agora-rtc-sdk-ng-4.16@npm:agora-rtc-sdk-ng@4.16.0 --save-exact
   pnpm add agora-rtc-sdk-ng@4.22.0 --save-exact

   然后将代码中原来的 import AgoraRTC from "agora-rtc-sdk-ng" 替换为如下行：

   Copy Text

   import AgoraRTC from "agora-rtc-sdk-ng-4.16"

   注意

   保留两个版本的 RTC 库会增加项目的包体积。

   Copy Text

   yarn add agora-rtm

   如果项目使用的 RTC 版本与 RTM 中依赖的 RTC 版本不一致，会收到提示：unmet peer agora-rtc-sdk-ng@4.22.0: found 4.16.0。此时你需要升级 RTC 的版本：

   Copy Text

   yarn upgrade agora-rtc-sdk-ng@4.22.0

   或者通过以下命令同时保留两个版本的 RTC 库：

   Copy Text

   yarn add agora-rtc-sdk-ng-4.16@npm:agora-rtc-sdk-ng@4.16.0 --save-exact
   yarn add agora-rtc-sdk-ng@4.22.0 --save-exact

   然后将代码中原来的 import AgoraRTC from "agora-rtc-sdk-ng" 替换为如下行：

   Copy Text

   import AgoraRTC from "agora-rtc-sdk-ng-4.16"

   注意

   保留两个版本的 RTC 库会增加项目的包体积。

   场景三：你的项目是全新的，且需要同时集成 RTM 和 RTC，以利用其共频道、数据优先级控制等能力。这种场景下建议你集成融合版本的 SDK。

   使用 npm使用 pnpm使用 Yarn

   Copy Text

   npm install agora-rtx

   Copy Text

   pnpm add agora-rtx --shamefully-hoist

   Copy Text

   # 若版本为 2.2.0
   # yarn add agora-rtx
   # yarn add agora-rtc-sdk-ng@4.22.0 --save-exact
   
   # 2.2.0 及之后版本
   yarn add agora-rtx

2. 完成安装后，在你的 app.js 中引入 RTM：

   Copy Text

   // 如果安装的是 agora-rtm
   import AgoraRTM from 'agora-rtm';
   
   // 如果安装的是融合版 agora-rtx
   // import AgoraRTM from 'agora-rtx';
   // import AgoraRTC from 'agora-rtc-sdk-ng';

构建项目Copy Anchor Link

1. 项目配置Copy Anchor Link

新建一个文件夹存放项目文件，进入文件夹中为你的 App 创建文件并安装其他依赖项。以下为在终端操作的命令行示例：

mkdir HelloWorld
cd HelloWorld
# Your app is in index.html.
touch index.html

2. 初始化 RTMCopy Anchor Link

初始化 rtm 时，你需要提供如下信息：

• 从控制台获取的 App ID（appId）。
• 你自行定义的用户 ID（userId），你需要保证其全局唯一性。

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Text Display App</title>
  <style>
    #container {
      width: 800px;
      margin: 0 auto;
      padding: 20px;
    }
    #textDisplay {
      width: 100%;
      height: 800px;
      border: 1px solid #b0b0b0;
      margin-bottom: 20px;
      overflow: auto;
      text-align: left;
      padding: 10px;
      box-sizing: border-box;
    }
    #inputContainer {
      display: flex;
      align-items: center;
    }
    #textInput {
      width: calc(100% - 100px);
      padding: 5px;
      margin-right: 10px;
    }
    #submitButton {
      width: 90px;
      padding: 5px;
    }
  </style>
  <script src="./AgoraRTM-production.js"></script>
</head>
<body>
  <script>
    const { RTM } = AgoraRTM;
    // Fill in the App ID of your project.
    const appId = "your_appId";
    // Fill in your user ID.
    const userId = "your_userId";
    // Fill in your channel name.
    let rtm;
    const msChannelName = "Chat_room";
    const buttonClick = () => {
      var input = document.getElementById("textInput");
      publishMessage(input.value);
      input.value = '';
    }
    const setupRTM = async () => {
      // Initialize the RTM client.
      try {
        rtm = new RTM(appId, userId);
      } catch (status) {
        console.log("Error");
        console.log(status);
      }

      // Add the event listener.

      // Log in the RTM server.

      // Subscribe to a channel.

    }
    // Publish a message.
    const showMessage = (user, msg) => {
      // Get text from the text box.
      const inputText = textInput.value;
      const newText = document.createTextNode(user + ": " + msg);
      const newLine = document.createElement("br");
      textDisplay.appendChild(newText);
      textDisplay.appendChild(newLine);
    }
    window.onload = setupRTM;
  </script>
  <div id="container">
    <h1>Hello RTM !</h1>
    <div>
      <div id="textDisplay"></div>
    </div>
    <div id="inputContainer">
      <input type="text" id="textInput" placeholder="Enter text">
      <button id="submitButton" onclick="buttonClick()"> Send </button>
    </div>
  </div>
</body>
</html>

3. 添加事件监听Copy Anchor Link

事件监听程序帮助你实现频道中消息、事件到达后的处理逻辑，添加以下代码到你的程序中以显示收到的消息或事件通知：

// Paste the following code snippet below "Add the event listener" comment
// Message event handler.
rtm.addEventListener("message", event => {
  showMessage(event.publisher, event.message);
});
// Pressence event handler.
rtm.addEventListener("presence", event => {
  if (event.eventType === "SNAPSHOT") {
    showMessage("INFO", "I Join");
  }
  else {
    showMessage("INFO", event.publisher + " is " + event.eventType);
  }
});
// Link state changed event handler.
rtm.addEventListener("linkState", event => {
  const currentState = event.currentState;
  const previousState = event.previousState;
  const serviceType = event.serviceType;
  const operation = event.operation;
  const reason = event.reason;
  const affectedChannels = event.affectedChannels;
  const timestamp = event.timestamp;
  const isResumed = event.isResumed;
  showMessage("INFO", JSON.stringify(event));
});

4. 登录服务Copy Anchor Link

你需要执行登录操作才能建立与 RTM 服务器的连接，然后才能调用 SDK 的其他 API。将以下代码添加到程序中，并传入你在服务端自行生成的 Token：

// Paste the following code snippet below "Log in the RTM server." comment
try {
  const result = await rtm.login({ token: 'your_token' });
  console.log(result);
} catch (status) {
  console.log(status);
}

5. 收发消息Copy Anchor Link

调用 publish 方法向 Message Channel 发送消息后，RTM 会把该消息分发给该频道的所有订阅者，以下代码演示如何发送字符串类型的消息，将此代码片段添加到程序中：

// Paste the following code snippet below "Publish a message" comment
const publishMessage = async (message) => {
  const payload = { type: "text", message: message };
  const publishMessage = JSON.stringify(payload);
  const publishOptions = { channelType: 'MESSAGE'}
  try {
    const result = await rtm.publish(msChannelName, publishMessage, publishOptions);
    showMessage(userId, publishMessage);
    console.log(result);
  } catch (status) {
    console.log(status);
  }
}

调用 subscribe 方法订阅此频道以接收此频道中的消息。将以下代码添加到程序中：

// Paste the following code snippet below "Subscribe to a channel." comment
try {
  const result = await rtm.subscribe(msChannelName);
  console.log(result);
} catch (status) {
  console.log(status);
}

如需了解更多收发消息的信息，查看消息。

6. 组合到一起Copy Anchor Link

经过上述步骤，你程序中的代码应该如下所示：

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Text Display App</title>
  <style>
    #container {
      width: 800px;
      margin: 0 auto;
      padding: 20px;
    }
    #textDisplay {
      width: 100%;
      height: 800px;
      border: 1px solid #b0b0b0;
      margin-bottom: 20px;
      overflow: auto;
      text-align: left;
      padding: 10px;
      box-sizing: border-box;
    }
    #inputContainer {
      display: flex;
      align-items: center;
    }
    #textInput {
      width: calc(100% - 100px);
      padding: 5px;
      margin-right: 10px;
    }
    #submitButton {
      width: 90px;
      padding: 5px;
    }
  </style>
  <script src="./AgoraRTM-production.js"></script>
</head>
<body>
  <script>
    const { RTM } = AgoraRTM;
    // Fill in the App ID of your project.
    const appId = "your_appId";
    // Fill in your user ID.
    const userId = "your_userId";
    // Fill in your channel name.
    let rtm;
    const msChannelName = "Chat_room";
    const buttonClick = () => {
      var input = document.getElementById("textInput");
      publishMessage(input.value);
      input.value = '';
    }
    const setupRTM = async () => {
      // Initialize the RTM client.
      try {
        rtm = new RTM(appId, userId);
      } catch (status) {
        console.log("Error");
        console.log(status);
      }
      // Add the event listener.
      // Message event handler.
      rtm.addEventListener("message", event => {
        showMessage(event.publisher, event.message);
      });
      // Pressence event handler.
      rtm.addEventListener("presence", event => {
        if (event.eventType === "SNAPSHOT") {
          showMessage("INFO", "I Join");
        }
        else {
          showMessage("INFO", event.publisher + " is " + event.eventType);
        }
      });
      // Link state changed event handler.
      rtm.addEventListener("linkState", event => {
        const currentState = event.currentState;
        const previousState = event.previousState;
        const serviceType = event.serviceType;
        const operation = event.operation;
        const reason = event.reason;
        const affectedChannels = event.affectedChannels;
        const timestamp = event.timestamp;
        const isResumed = event.isResumed;
        showMessage("INFO", JSON.stringify(event));
      });
      // Log in the RTM server.
      try {
        const result = await rtm.login({  token: 'your_token' });
        console.log(result);
      } catch (status) {
        console.log(status);
      }
      // Subscribe to a channel.
      try {
        const result = await rtm.subscribe(msChannelName);
        console.log(result);
      } catch (status) {
        console.log(status);
      }
    }
    const publishMessage = async (message) => {
      const payload = { type: "text", message: message };
      const publishMessage = JSON.stringify(payload);
      const publishOptions = { channelType: 'MESSAGE'}
      try {
        const result = await rtm.publish(msChannelName, publishMessage, publishOptions);
        showMessage(userId, publishMessage);
        console.log(result);
      } catch (status) {
        console.log(status);
      }
    }
    const showMessage = (user, msg) => {
      // Get text from the text box.
      const inputText = textInput.value;
      const newText = document.createTextNode(user + ": " + msg);
      const newLine = document.createElement("br");
      textDisplay.appendChild(newText);
      textDisplay.appendChild(newLine);
    }
    window.onload = setupRTM;
  </script>
  <div id="container">
    <h1>Hello RTM !</h1>
    <div>
      <div id="textDisplay"></div>
    </div>
    <div id="inputContainer">
      <input type="text" id="textInput" placeholder="Enter text">
      <button id="submitButton" onclick="buttonClick()"> Send </button>
    </div>
  </div>
</body>
</html>