How to Define Callbacks in Android?

Question

During the most recent Google IO, there was a presentation about implementing restful client applications. Unfortunately, it was only a high level discussion with no source

Answer 1

You can also use LocalBroadcast for this purpose. Here is a quick quide

Create a broadcast receiver:

   LocalBroadcastManager.getInstance(this).registerReceiver(
            mMessageReceiver, new IntentFilter("speedExceeded"));

private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        Double currentSpeed = intent.getDoubleExtra("currentSpeed", 20);
        Double currentLatitude = intent.getDoubleExtra("latitude", 0);
        Double currentLongitude = intent.getDoubleExtra("longitude", 0);
        //  ... react to local broadcast message
    }

This is how you can trigger it

Intent intent = new Intent("speedExceeded");
intent.putExtra("currentSpeed", currentSpeed);
intent.putExtra("latitude", latitude);
intent.putExtra("longitude", longitude);
LocalBroadcastManager.getInstance(this).sendBroadcast(intent);

unRegister receiver in onPause:

protected void onPause() {
  super.onPause();
  LocalBroadcastManager.getInstance(this).unregisterReceiver(mMessageReceiver);
}