Question

MQTT协议的新手。我的代码在eclipse平台上运行良好。现在，尝试为android编写发布者mqtt客户端，订阅者正在eclipse上运行。应用程序在发布后即将关闭。请帮我完成以下代码。

public class MainActivity extends AppCompatActivity 
{
  String text="HELOOO";
  TextView  textReply;
  private MqttClient client;
  public static final String TOPIC = "data";
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    try {
      client = new MqttClient("http://IP-address:1883",     MqttClient.generateClientId());
    } catch (MqttException e) {
      e.printStackTrace();
      System.exit(1);
    }
    try {
      client.connect();

      MqttMessage mssg=new MqttMessage();
      mssg.setPayload(text.getBytes());

      client.disconnect();

    } catch (MqttException e) {
      e.printStackTrace();
      System.exit(1);
    }

  }
}

@arjun建议后的更改

public class MainActivity extends AppCompatActivity {
String text="HELOOO";
TextView  textReply;
private MqttClient client;
public static final String TOPIC = "iot_data";
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Publisher myClientTask = new Publisher();
    myClientTask.execute();



}
}
class Publisher  extends AsyncTask<Void, Void, Void>{
String text="helloo";
@Override

protected Void doInBackground(Void... voids) {
    try {
        MqttClient client = new MqttClient("tcp://Ip:1883", MqttClient.generateClientId());
        client.connect();
        MqttMessage mssg=new MqttMessage();
        mssg.setPayload(text.getBytes());
        client.publish("iot_data",mssg);
        client.disconnect();
    }catch(Exception e)
    {


    }


    return null;
}

}

Answer 1

也许它与您没有在客户端上正确指定ip地址有关，导致您执行system.exit（1）的异常;

Android Mqtt Publisher应用程序意外停止

1 个答案: