Android -- Handler

public class MainActivity extends Activity {private Button btn1;private ProgressBar pb;int i=0;private Handler handler =new Handler(){public void handleMessage(Message msg) {super.handleMessage(msg);pb.setProgress(msg.arg1);handler.post(runnable);if (msg.arg1==100) {handler.removeCallbacks(runnable);}}};Runnable runnable =new Runnable() {@Overridepublic void run() {i=i+10;Message message= new Message();message.arg1=i;try {Thread.sleep(500);} catch (InterruptedException e) {e.printStackTrace();}handler.sendMessage(message);}};@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);btn1=(Button) findViewById(R.id.button1);pb=(ProgressBar) findViewById(R.id.progressBar1);btn1.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {handler.post(runnable);}});}}