1. FirstActivity

public class FirstActivity extends AppCompatActivity {    private static int count = 0;    public static final int SET = 1;  //设置一个what标记    private Handler myHandle = new Handler() {      //定义Handler对象        @Override        public void handleMessage(Message msg) {            switch (msg.what) {     //判断操作类型                case SET:                    FirstActivity.this.info.setText("dailei---"+count++);            }            super.handleMessage(msg);        }    };    private TextView info  = null;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        super.setContentView(R.layout.activity_main);        this.info = (TextView)findViewById(R.id.info);        Timer timer = new Timer();      //定义调度器        timer.schedule(new MyTask(),0,1000);        //立即开始，每隔1秒增长    }    /**     * 定义定时调度的具体实现类     */    private class MyTask extends TimerTask{        @Override        public void run() {            Message msg = new Message();    //定义message            msg.what = SET;        //操作为设置显示文字            FirstActivity.this.myHandle.sendMessage(msg);     //发送消息到子线程        }    }}

2. activity_main.xml