java - 如何使用广播接收器警报管理器每 10 秒向服务器发送一次文本

Question

        package com.frost.mqtttutorial;

    import android.Manifest;
    import android.app.AlarmManager;
    import android.app.PendingIntent;
    import android.content.Context;
    import android.content.Intent;
    import android.location.Location;
    import android.support.v4.app.ActivityCompat;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.util.Log;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.TextView;
    import android.widget.Toast;

    import com.github.mikephil.charting.charts.LineChart;

    import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
    import org.eclipse.paho.client.mqttv3.MqttCallbackExtended;
    import org.eclipse.paho.client.mqttv3.MqttMessage;

    import helpers.ChartHelper;
    import helpers.MqttHelper;

    public class MainActivity extends AppCompatActivity {

        MqttHelper mqttHelper;
        ChartHelper mChart;
        LineChart chart;

        TextView dataReceived;
        EditText textMessage;
        Button publishMessage, stop, btnLoc;
        private AlarmManager manager;

        @Override

        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);

            setContentView(R.layout.activity_main);


            dataReceived = (TextView) findViewById(R.id.dataReceived);
            textMessage = (EditText) findViewById(R.id.textMessage);
            publishMessage = (Button) findViewById(R.id.publishMessage);
            publishMessage.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View view) {





                    Intent alarmIntent = new Intent(MainActivity.this, AlarmReceiver.class);
                    PendingIntent pendingIntent = PendingIntent.getBroadcast(MainActivity.this, 0, alarmIntent, 0);


                    manager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
                    manager.setInexactRepeating(AlarmManager.RTC_WAKEUP, 0,10000, pendingIntent);
                    String msg = textMessage.getText().toString();
                    mqttHelper.publishTopic(msg);

                }
            });
            startMqtt();
            stop=(Button) findViewById(R.id.stop);
            stop.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Intent intent1   = new Intent(MainActivity.this, AlarmReceiver.class);
                    PendingIntent pendingIntent = PendingIntent.getBroadcast(MainActivity.this, 0, intent1, 0);
                 AlarmManager manager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
                    manager.cancel(pendingIntent);
                    Toast.makeText(v.getContext(), "Cancelled alarm", Toast.LENGTH_SHORT).show();

                }
            });


        }




        private void startMqtt(){
            mqttHelper = new MqttHelper(getApplicationContext());
            mqttHelper.mqttAndroidClient.setCallback(new MqttCallbackExtended() {
                @Override
                public void connectComplete(boolean b, String s) {

                    Toast.makeText(MainActivity.this,"Connected",Toast.LENGTH_LONG).show();
                }

                @Override
                public void connectionLost(Throwable throwable) {
                    Toast.makeText(MainActivity.this,"Connection failed",Toast.LENGTH_LONG).show();
                }

                @Override
                public void messageArrived(String topic, MqttMessage mqttMessage) throws Exception {
                    Log.w("Debug",mqttMessage.toString());
                    dataReceived.setText(mqttMessage.toString());
                    mChart.addEntry(Float.valueOf(mqttMessage.toString()));
                }

                @Override
                public void deliveryComplete(IMqttDeliveryToken iMqttDeliveryToken) {

                }
            });
        }
    }

下面的代码是连接服务器和发布消息

package helpers;
import android.content.Context;
import android.support.v4.content.LocalBroadcastManager;
import android.util.Log;
import com.frost.mqtttutorial.AlarmReceiver;
import org.eclipse.paho.android.service.MqttAndroidClient;
import org.eclipse.paho.client.mqttv3.DisconnectedBufferOptions;
import org.eclipse.paho.client.mqttv3.IMqttActionListener;
import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.IMqttToken;
import org.eclipse.paho.client.mqttv3.MqttCallbackExtended;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;

public class MqttHelper {
    public MqttAndroidClient mqttAndroidClient;
    final String serverUri = "";  
    final String clientId ="";
    final String subscriptionTopic = "";
    final String publishTopic = "";
    final String username = "";
    final String password = "";

    public MqttHelper(Context context){
         mqttAndroidClient = new MqttAndroidClient(context, serverUri, clientId);
        mqttAndroidClient.setCallback(new MqttCallbackExtended() {
        @Override
        public void connectComplete(boolean b, String s) {
            Log.w("mqtt", s);
        }

        @Override
        public void connectionLost(Throwable throwable) {

        }

        @Override
        public void messageArrived(String topic, MqttMessage mqttMessage) throws Exception {
            Log.w("Mqtt", mqttMessage.toString());
        }

        @Override
        public void deliveryComplete(IMqttDeliveryToken iMqttDeliveryToken) {

        }
    });
    connect();
}

    public void setCallback(MqttCallbackExtended callback) {
        mqttAndroidClient.setCallback(callback);
    }

    private void connect(){
        MqttConnectOptions mqttConnectOptions = new MqttConnectOptions();
        mqttConnectOptions.setAutomaticReconnect(true);
        mqttConnectOptions.setCleanSession(false);
        mqttConnectOptions.setUserName(username);
        mqttConnectOptions.setPassword(password.toCharArray());

        try {

            mqttAndroidClient.connect(mqttConnectOptions, null, new IMqttActionListener() {
                @Override
                public void onSuccess(IMqttToken asyncActionToken) {

                    DisconnectedBufferOptions disconnectedBufferOptions = new DisconnectedBufferOptions();
                    disconnectedBufferOptions.setBufferEnabled(true);
                    disconnectedBufferOptions.setBufferSize(100);
                    disconnectedBufferOptions.setPersistBuffer(false);
                    disconnectedBufferOptions.setDeleteOldestMessages(false);
                    mqttAndroidClient.setBufferOpts(disconnectedBufferOptions);
                    subscribeToTopic();

                }

                @Override
                public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                    Log.w("Mqtt", "Failed to connect to: " + serverUri + exception.toString());


                }

            });


        } catch (MqttException ex){
            ex.printStackTrace();
        }
    }

    private void subscribeToTopic() {
        try {
            mqttAndroidClient.subscribe(subscriptionTopic, 0, null, new IMqttActionListener() {
                @Override
                public void onSuccess(IMqttToken asyncActionToken) {

                    Log.w("Mqtt","Subscribed!");
                }

                @Override
                public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                   Log.w("Mqtt", "Subscribed fail!");


                }
            });

        } catch (MqttException ex) {
            System.err.println("Exception whilst subscribing");
            ex.printStackTrace();
        }
    }

    public void publishTopic(String msg) {

        MqttMessage message = new MqttMessage();
        message.setRetained(true);
        message.setPayload(msg.getBytes());

            try {
                mqttAndroidClient.publish(publishTopic, message);
            } catch (MqttException e) {
                e.printStackTrace();
            }

    }
}
`

下面是通过广播接收器发送消息的代码

package com.frost.mqtttutorial;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.location.Location;
import android.net.ConnectivityManager;
import android.os.SystemClock;
import android.util.Log;
import android.widget.Toast;

import org.eclipse.paho.android.service.MqttAndroidClient;
import org.eclipse.paho.client.mqttv3.DisconnectedBufferOptions;
import org.eclipse.paho.client.mqttv3.IMqttActionListener;
import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.IMqttToken;
import org.eclipse.paho.client.mqttv3.MqttCallbackExtended;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;

import helpers.MqttHelper;


public class AlarmReceiver extends BroadcastReceiver {


   public void onReceive(Context context, Intent intent){

        Log.d("Alarm", "Alarm receive");
    }

}

Answer 1

Handler 以便每 10 秒执行一次。

Handler handler = new Handler();
Runnable test = new Runnable() {
    @Override
    public void run() {
        //do work
        //String msg = textMessage.getText().toString();
        // send message to server
        handler.post(test, 10000); //wait 10 sec and run again
    }
};

public void stopTest() {
    handler.removeCallbacks(test);
}

public void startTest() {
    handler.post(test,0); //wait 0 ms and run
}

引用:https://stackoverflow.com/a/41395577/9909365