eclipse安卓开发，实时显示系统时间

private TextView tv_time;
private static final int msgKey1 = 1;

  @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_3_4_6);
        
        tv_time = (TextView) findViewById(R.id.mytime);
        new TimeThread().start();
    }

 public class TimeThread extends  Thread{
        @Override
        public void run() {
            super.run();
            do{
                try {
                    Thread.sleep(1000);
                    Message msg = new Message();
                    msg.what = msgKey1;
                    mHandler.sendMessage(msg);

                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }while (true);
        }
    }