BroadcastReceiver在Android上没有按预期工作

Posted 2021-04-09

我知道这已被问过很多次，但我无法让这个工作。我查看了android文档和其他来源。我得到了这个活动，里面有一个广播接收器变量，并在构造函数中启动一个服务：

private BroadcastReceiver mReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        Toast.makeText(getApplicationContext(), "Received", Toast.LENGTH_SHORT).show();
    }
};

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_compass);
    Intent mIntent = new Intent(this, GPSTracker.class);
    startService(mIntent);
}

@Override
public void onResume() {
    super.onResume();
    registerReceiver(mReceiver, new IntentFilter());
}

@Override
protected void onStop() {
    unregisterReceiver(mReceiver);
    super.onStop();
}

我把服务放在清单中，我确信它能正常工作。任何帮助将不胜感激。

广播接收器应该定期从服务中接收2个浮点数。

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="jemboy.compass" >
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <service
        android:name=".GPSTracker"></service>
    <activity
        android:name=".MainActivity"
        android:label="@string/app_name" >
    </activity>
    <activity android:name=".CompassActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name=".OtherActivity"></activity>
</application>

答案

在活动中

private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        if (intent.getAction().equals(UPDATE_PLAYER)) {
            updateMediaPlayerToggle();
        } else if (intent.getAction().equals(BUFFERING)) {
            showMediaPlayerBuffering();
        }
    }
};
private void registerBroadcastReceiver() {
    LocalBroadcastManager broadcastManager = LocalBroadcastManager.getInstance(this);
    IntentFilter updateIntentFilter = new IntentFilter();
    updateIntentFilter.addAction(UPDATE_PLAYER);
    updateIntentFilter.addAction(BUFFERING);
    broadcastManager.registerReceiver(broadcastReceiver, updateIntentFilter);
}

在服务中。

private void sendUpdatePlayerIntent() {
    Log.d(TAG, "updatePlayerIntent");
    Intent updatePlayerIntent = new Intent(MainActivity.UPDATE_PLAYER);
    LocalBroadcastManager.getInstance(this).sendBroadcast(updatePlayerIntent);
}

来自媒体播放器服务的示例。