Android常用定时器的实现方式

public class HandlerAndSleep {

    // 1、定义一个Handler类，用于处理接受到的Message.
    Handler handler = new Handler(Looper.getMainLooper()) {
        @Override
        public void handleMessage(@NonNull Message msg) {
            super.handleMessage(msg);
            // do something eg.
            Log.d("HandlerAndSleep", "HandlerAndSleep");
        }
    };

    // 2、新建一个实现Runnable接口的线程类
    class MyThread implements Runnable {
        @Override
        public void run() {
            while (true) {
                try {
                    Thread.sleep(10000);
                    Message message = new Message();
                    message.what = 1;
                    handler.sendMessage(message);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    }

    public HandlerAndSleep() {
        //3、在需要启动线程的地方加入下面语句,启动线程后，线程每10s发送一次消息
        new Thread(new MyThread()).start();
    }
}

public class HandleAndPostDelayed {

    Handler handler = new Handler(){
        @Override
        public boolean sendMessageAtTime(@NonNull Message msg, long uptimeMillis) {
            Log.d("HandleAndPostDelayed", "HandleAndPostDelayed");
            return super.sendMessageAtTime(msg, uptimeMillis);
        }
    };

    Runnable runnable = new Runnable() {
        @Override
        public void run() {
            // do something
            handler.postDelayed(this, 2000);
        }
    };

    HandleAndPostDelayed() {
    	// 开启定时器
        handler.postDelayed(runnable, 2000);
		// 停止定时器
//        handler.removeCallbacks(runnable);
    }
}

public class HandlerAndTimer {

    private final Timer timer = new Timer();
    private TimerTask task;
    Handler handler = new Handler() {

        @Override
        public void handleMessage(@NonNull Message msg) {
            // do something
            Log.d("HandlerAndTimer", "HandlerAndTimer");
            super.handleMessage(msg);
        }
    };

    public HandlerAndTimer() {
        task = new TimerTask() {
            @Override
            public void run() {
                Message message = new Message();
                message.what = 1;
                handler.sendMessage(message);
            }
        };
        //启动定时器 参数对应为 TimerTask 延迟时间 间隔时间
        timer.schedule(task, 2000, 2000);
    }
}

public class MainActivity extends AppCompatActivity {

    Handler handler = new Handler() {
        @Override
        public void handleMessage(@NonNull Message msg) {
            tCount++;
            timerTV.setText(tCount+"");
            super.handleMessage(msg);
        }
    };

    Timer timer = new Timer();
    int tCount = 0;
    int sCount = 0;
    TextView timerTV;
    TextView serviceTV;

    String ALARM_RECEIVER_ACTION = "com.yh.study.AlarmReceiver";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        timerTV = findViewById(R.id.timer_tv);
        serviceTV = findViewById(R.id.service_tv);

        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                handler.sendEmptyMessage(0);
            }
        }, 2*1000, 5*1000);

        AlarmReceiver alarmReceiver = new AlarmReceiver(new Handler() {
            @Override
            public void handleMessage(@NonNull Message msg) {
                sCount++;
                serviceTV.setText(sCount+"");
                super.handleMessage(msg);
            }
        });
        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction(ALARM_RECEIVER_ACTION);
        registerReceiver(alarmReceiver, intentFilter);

        Intent intent = new Intent(ALARM_RECEIVER_ACTION);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(MainActivity.this, 0, intent, 0);
//
        AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
        alarmManager.setExactAndAllowWhileIdle(AlarmManager.ELAPSED_REALTIME_WAKEUP, SystemClock.elapsedRealtime(),
                pendingIntent);
    }
}

public class AlarmReceiver extends BroadcastReceiver {
    Handler handler;
    AlarmReceiver(Handler handler) {
        this.handler = handler;
    }

    @Override
    public void onReceive(Context context, Intent intent) {
        Log.d("onReceive", "onReceive");
        handler.sendEmptyMessage(0);
        Intent serviceIntent = new Intent(context, MyService.class);
        context.startService(serviceIntent);
    }
}

public class MyService extends IntentService {
    public MyService() {
        super("MyService");
    }

    @Override
    protected void onHandleIntent(@Nullable Intent intent) {
        AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);

        Intent alarmIntent = new Intent("com.yh.study.AlarmReceiver");
        PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0, alarmIntent, 0);
        alarmManager.setExactAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, System.currentTimeMillis()+5*1000,
                pendingIntent);
    }
}

private final Timer timer = new Timer();
private TimerTask task;
Handler handler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
        // TODO Auto-generated method stub
        // 要做的事情
        super.handleMessage(msg);
    }
};

task = new TimerTask() {
    @Override
    public void run() {
        // TODO Auto-generated method stub
        Message message = new Message();
        message.what = 1;
        handler.sendMessage(message);
    }
};

timer.schedule(task, 2000, 2000);