Android：将传感器数据从服务广播到活动
我正在尝试学习Android应用程序开发，并编写了一个非常简单的应用程序，其中包含一个调用服务的活动。 该服务将测量的加速度广播到活动。 问题是服务运行正常，但它不会将数据发送回活动。 即，我的接收器上的onReceive永远不会被调用。 此外，当活动结束时，有一个例外，说我的接收器尚未注册。 下面是我的服务，活动和manifest.xml的代码。 任何帮助将非常感谢。
活动呼叫服务：
package com.practice; import com.practice.SimpleService; import android.app.Activity; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; import android.os.Bundle; import android.util.Log; import android.view.Window; public class ServiceActivity extends Activity { MyReceiver myReceiver=null; Intent i; static final String LOG_TAG = "ServiceActivity"; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { Log.d( LOG_TAG, "onCreate" ); super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.main); //Start service i= new Intent(this, com.practice.SimpleService.class); Log.d( LOG_TAG, "onCreate/startService" ); } @Override public void onResume(){ super.onResume(); Log.d( LOG_TAG, "onResume/registering receiver" ); //Register BroadcastReceiver to receive accelerometer data from service //if (myReceiver == null){ myReceiver = new MyReceiver(); IntentFilter intentFilter = new IntentFilter(); intentFilter.addAction(SimpleService.MY_ACTION); startService(i); registerReceiver(myReceiver, intentFilter); //} } @Override public void onPause(){ super.onPause(); Log.d( LOG_TAG, "onPause/unregistering receiver" ); stopService(i); if (myReceiver != null)unregisterReceiver(myReceiver); } @Override protected void onStop(){ super.onStop(); Log.d( LOG_TAG, "onStop" ); if (myReceiver != null) unregisterReceiver (myReceiver); stopService(i); } private class MyReceiver extends BroadcastReceiver{ static final String Log_Tag = "MyReceiver"; @Override public void onReceive(Context arg0, Intent arg1){ Log.d( LOG_TAG, "onReceive" ); String measurement = arg1.getStringExtra("measurement"); System.out.println("I am here"); } } }
服务获取传感器数据：
package com.practice; import java.util.List; import android.app.Service; import android.content.Intent; import android.hardware.Sensor; import android.hardware.SensorEvent; import android.hardware.SensorEventListener; import android.hardware.SensorManager; import android.os.IBinder; import android.util.Log; import android.widget.TextView; public class SimpleService extends Service implements SensorEventListener{ final static String MY_ACTION = "MY_ACTION"; private TextView output; private String reading; private SensorManager mgr; private List sensorList; static final String LOG_TAG = "SimpleService"; Intent intent = new Intent("com.practice.SimpleService.MY_ACTION"); @Override //public void onStartCommand() { public void onCreate() { Log.d( LOG_TAG, "onStartCommand" ); mgr = (SensorManager) getSystemService(SENSOR_SERVICE); sensorList = mgr.getSensorList(Sensor.TYPE_ACCELEROMETER); for (Sensor sensor : sensorList) { mgr.registerListener(this, sensor, SensorManager.SENSOR_DELAY_NORMAL); } } @Override public void onDestroy() { Log.d( LOG_TAG, "onDestroy" ); mgr.unregisterListener(this); super.onDestroy(); } @Override public IBinder onBind(Intent arg0) { // TODO Auto-generated method stub return null; } @Override public void onAccuracyChanged(Sensor sensor, int accuracy) { // TODO Auto-generated method stub } @Override public void onSensorChanged(SensorEvent event) { Log.d( LOG_TAG, "onSensorChanged" ); StringBuilder builder = new StringBuilder(); for (int i = 0; i < event.values.length; i++) { builder.append(" ["); builder.append(i); builder.append("] = "); builder.append(event.values[i]); builder.append("\n"); } reading=builder.toString(); //Send back reading to Activity intent.putExtra("measurement", reading); sendBroadcast(intent); }
}
的Manifest.xml
创建自定义意图：
final static String MY_ACTION = "com.practice.SimpleService.MY_ACTION";
在Manifest.xml中
有关自定义广播的详细信息，请参阅自定义意图和使用接收器进行广播