public class MainActivity extends Activity {     private Button btnClick=null;     private Button btnStop=null;     private TextView tvShow=null;     private String info="";     private Timer timer=null;     @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);         btnClick=(Button)findViewById(R.id.btn_click);         btnStop=(Button)findViewById(R.id.btn_stop);         tvShow=(TextView)findViewById(R.id.tv_show);         timer=new Timer();         btnClick.setOnClickListener(new OnClickListener(){             public void onClick(View view){                 timer.scheduleAtFixedRate(new MyTask(), 100, 2000);             }         });         btnStop.setOnClickListener(new OnClickListener(){             public void onClick(View view){                 timer.cancel();             }         });     }         Handler myHandler=new Handler(){         public void handleMessage(Message msg){             if(info!=""){                 tvShow.setText(info);             }         }     };     private class MyTask extends TimerTask{         public void run(){             String param="http://192.168.0.116/android/time.php";             info=HttpHelper.getStringFromNet2(param);             myHandler.obtainMessage(100).sendToTarget();         }     } }