android - 设备上 IntentFilter 分辨率的奇怪行为

Question

我正在试验 requestLocationUpdates(String provider, long minTime, float minDistance, PendingIntent intent) 和 BroadcastReceiver。代码如下:

// PendingLocationDemo.java
public class PendingLocationDemo extends Activity {

    public TextView output;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        output = (TextView) findViewById(R.id.output);
        SomeReceiver receiver = new SomeReceiver(this);
        IntentFilter filter = new IntentFilter();
        filter.addAction("some_action");
        // filter.addAction("some_other_action");
        // filter.addAction("still_something_different");
        filter.addCategory(Intent.CATEGORY_DEFAULT);
        getApplicationContext().registerReceiver(receiver, filter);
        Intent intent = new Intent();
        intent.setAction("some_action");
        PendingIntent pending = PendingIntent.getBroadcast(
                getApplicationContext(), 0, intent,
                PendingIntent.FLAG_CANCEL_CURRENT);
        // Get the location manager
        LocationManager locationManager = (LocationManager) 
                getSystemService(LOCATION_SERVICE);
        locationManager.requestLocationUpdates(
                LocationManager.GPS_PROVIDER, 3000, 0, pending);
    }

    protected void someCallback(Intent intent) {
        printObject(intent);
    }
}

// SomeReceiver.java
public class SomeReceiver extends BroadcastReceiver {

    PendingLocationDemo caller;

    public SomeReceiver(PendingLocationDemo caller) {
        this.caller = caller;
    }

    @Override
    public void onReceive(Context context, Intent intent) {
        caller.someCallback(intent);
    }
}

当我在设备上运行它时，输出取决于我在 IntentFilter 中用于操作的值。

• 对于“some_action”，输出是:Intent { act=some_action cat=[android.intent.category.DEFAULT](有额外的)
• 对于“some_other_action”，输出是:Intent { act=some_other_action(有附加功能)}
• 对于“still_something_different”，我没有收到更新。

对于这种不一致的行为是否有合理的解释？

Answer 1

这种奇怪的行为是由于广播接收器的注册。您可以在位置监听器中编写代码，而不是注册广播接收器，它也是一个广播接收器并在后台监听位置更新。

final LocationManager locationManager = (LocationManager) context
        .getSystemService(Context.LOCATION_SERVICE);
LocationListener locationListener = new LocationListener() {

    public void onLocationChanged(Location location) {
        // Code for action you wish to perform on Location Changed.
    }

    public void onStatusChanged(String provider, int status, Bundle extras) {}

    public void onProviderEnabled(String provider) {}

    public void onProviderDisabled(String provider) {}
};
// ...
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0,
            3000, locationListener);

希望对您有所帮助。