Toast.makeText(MainActivity.this,str,Toast.LENGTH_SHORT).show();
extends Service > onCreate, onDestroy, onStartCommand, onBind().
Intent intent = new Intent(MainActivity.this, ExapleService.class;
startService(intent);
stopService();
START_STICKY, START_NON_STICKY,START_REDELIVER_INTENT
Message.obtain() or Handler.obtainMessage() to get Message object. Remove from MessageQueue, put into
pool.
Looper 1to1 MessageQueue. e.g. Looper.myLooper()
Handler nto1 Looper/MessageQueue.
Looper looper = looper.getMainLooper();
handler=new ServiceHandler();
extends Handler
Message msg = Handler.obtainMessage();
msg.what="xxx";
msg.arg1="xxx";
msg.obj="xxx";
handler.sendMessage(msg);