Android 定时刷新UI

public class MainActivity extends Activity {private TextView title_date_time;private SimpleDateFormat df = null;private Timer mTimer = null;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);// set no titlerequestWindowFeature(Window.FEATURE_NO_TITLE);// set full screengetWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);setContentView(R.layout.activity_main);if (savedInstanceState == null) {getFragmentManager().beginTransaction().add(R.id.container, new PlaceholderFragment()).commit();}df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");// 设置日期格式startTimerTask();}private Handler mhandler = new Handler() {@Override           public void handleMessage(Message msg) {// 更新UIswitch (msg.what) {case 1:updateTitle();break;}}};private void updateTitle() {Log.v("MainActivity", "date time update " + df.format(new Date()));title_date_time.setText(df.format(new Date()));}@Overrideprotected void onStart() {// TODO Auto-generated method stubsuper.onStart();}private boolean startTimerTask(){if(mTimer == null){Log.v("MainActivity", "TimerTask start.");mTimer = new Timer(true);TimerTask mTimerTask = new TimerTask() {@Overridepublic void run() {if (title_date_time != null) {//Message message = new Message();//message.what = 1;mhandler.obtainMessage(1).sendToTarget();}}};mTimer.schedule(mTimerTask, 1000, 1000);}return true;}private boolean stopTimerTask(){if(mTimer != null){Log.v("MainActivity", "TimerTask stop.");mTimer.cancel();mTimer = null;}return true;}@Overrideprotected void onResume() {// TODO Auto-generated method stubsuper.onResume();/** * set horizontal display * */if (getRequestedOrientation() != ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE) {setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);}// RtmpPlayer rp = new RtmpPlayer();// rp.Play("rtmpt://192.168.1.132/vod/sample1_1500kbps.f4v"); title_date_time = (TextView) findViewById(R.id.title_date_time); title_date_time.setText(df.format(new Date()));  startTimerTask();// AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);//// Intent intent = new Intent(MainActivity.this, AlarmBroadCast.class);////// PendingIntent pendingIntent = PendingIntent.getBroadcast(// MainActivity.this, 0, intent, 0);//// am.setRepeating(AlarmManager.RTC_WAKEUP,// System.currentTimeMillis(), 1000, pendingIntent);}@Overrideprotected void onPause() {// TODO Auto-generated method stubsuper.onPause();stopTimerTask();}@Overrideprotected void onStop() {// TODO Auto-generated method stubsuper.onStop();}@Overrideprotected void onDestroy() {// TODO Auto-generated method stubsuper.onDestroy();stopTimerTask();}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.main, menu);return true;}@Overridepublic boolean onOptionsItemSelected(MenuItem item) {// Handle action bar item clicks here. The action bar will// automatically handle clicks on the Home/Up button, so long// as you specify a parent activity in AndroidManifest.xml.int id = item.getItemId();if (id == R.id.action_settings) {return true;}return super.onOptionsItemSelected(item);}/** * A placeholder fragment containing a simple view. */public static class PlaceholderFragment extends Fragment {public PlaceholderFragment() {}@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {View rootView = inflater.inflate(R.layout.fragment_main, container,false);return rootView;}}}