android - 从未调用过广播接收器 onReceive() - Android

Question

我一直在我的应用程序中测试发送和接收广播，但我遇到了问题。服务启动，我得到 Toast 表示广播已发送但 onReceive 从未在 myMapView 类中调用。我只在下面包含了我认为相关的代码...任何帮助将不胜感激。我认为我没有正确注册接收器。

提前致谢。

public class myLocationService extends Service implements LocationListener {
    private static final String GEO_LNG = "GEO_LNG";
    private static final String GEO_LAT = "GEO_LAT";

    private void updateWithNewLocation(Location location){


    if (location != null){

            Double geoLat = location.getLatitude() * 1E6;
            Double geoLng = location.getLongitude() * 1E6;

            Intent intent = new Intent(this, myMapView.class);
            intent.putExtra(GEO_LNG,geoLng);
            intent.putExtra(GEO_LAT, geoLat);
            sendBroadcast(intent);
            Toast.makeText(myLocationService.this, "Broadcast sent", Toast.LENGTH_SHORT).show();
        }   
    else{
        Toast.makeText(myLocationService.this, "Location = null", Toast.LENGTH_SHORT).show();
    }

}
}


public class myMapView extends MapActivity{
    private static final String GEO_LNG = "GEO_LNG";
    private static final String GEO_LAT = "GEO_LAT";


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.map_layout);     

    IntentFilter filter = new IntentFilter();
    filter.addAction(GEO_LONG);
    filter.addAction(GEO_LAT);
    registerReceiver(locationRec, filter);

    Intent i = new Intent(this, myLocationService.class);

            startService(i);
}

    private BroadcastReceiver locationRec = new BroadcastReceiver(){
        @Override
        public void onReceive(Context context, Intent intent) {
                       double geoLng = intent.getExtras().getDouble(GEO_LONG);
                       double geoLat = intent.getExtras().getDouble(GEO_LAT);
            Toast.makeText(GeoTrailsMap.this, "Got broadcast", Toast.LENGTH_LONG).show();


        }
    };

编辑 我已将代码修改为如下所示，但我仍然没有收到广播。

public class myLocationService extends Service implements LocationListener {
private static final String GEO_LNG = "GEO_LNG";
private static final String GEO_LAT = "GEO_LAT";
public static final String LOCATION_UPDATE = "LOCATION_UPDATE";

private void updateWithNewLocation(Location location){


if (location != null){

        Double geoLat = location.getLatitude() * 1E6;
        Double geoLng = location.getLongitude() * 1E6;

        Intent intent = new Intent(this, myMapView.class);
        intent.putExtra(GEO_LNG,geoLng);
        intent.putExtra(GEO_LAT, geoLat);
        intent.setAction(LOCATION_UPDATE);
        sendBroadcast(intent);
        Toast.makeText(myLocationService.this, "Broadcast sent",    Toast.LENGTH_SHORT).show();
    }   
    else{
    Toast.makeText(myLocationService.this, "Location = null", Toast.LENGTH_SHORT).show();
    }

}
}


public class myMapView extends MapActivity{
private static final String GEO_LNG = "GEO_LNG";
private static final String GEO_LAT = "GEO_LAT";
private static final String LOCATION_UPDATE = myLocationService.LOCATION_UPDATE;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.map_layout);     

    IntentFilter filter = new IntentFilter();
    filter.addAction(LOCATION_UPDATE);
    registerReceiver(locationRec, filter);

    Intent i = new Intent(this, myLocationService.class);

    startService(i);
}

private BroadcastReceiver locationRec = new BroadcastReceiver(){
    @Override
    public void onReceive(Context context, Intent intent) {
                   double geoLng = intent.getExtras().getDouble(GEO_LNG);
                   double geoLat = intent.getExtras().getDouble(GEO_LAT);
        Toast.makeText(GeoTrailsMap.this, "Got broadcast", Toast.LENGTH_LONG).show();


    }
};

Answer 1

正在触发的 Intent 没有 Action 集。当您在此处的 IntentFilter 中调用“addAction”时:

    IntentFilter filter = new IntentFilter();
    filter.addAction(GEO_LNG);
    filter.addAction(GEO_LAT);
    registerReceiver(locationRec, filter);

您正在添加接收器将监听的操作(在本例中，接收器将监听 GEO_LNG 和 GEO_LAT。

在您触发 Intent 的服务中， Intent 需要包含该操作以便接收者发现它。决定要发送哪一个，然后将 Intent-firing 代码修改为如下所示:

        Intent intent = new Intent(this, myMapView.class);
        // Here you're using GEO_LNG as both the Intent action, and a label 
        // for data being passed over.  Might want to change that for clarity?
        intent.putExtra(GEO_LNG, geoLng);
        intent.putExtra(GEO_LAT, geoLat);
        intent.setAction(GEO_LNG);
        ...