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Android常用定時器的實現(xiàn)方式_Android

作者：八塊的紅雙喜 ? 更新時間： 2022-10-30 編程語言

前言

android開發(fā)中，常用定時器實現(xiàn)方式有以下幾種：

1、Handler與sleep

2、Handler與postDelayed

3、Handler與timer

注：Handler的主要作用就是用來處理接收到的信息；用Handler消息傳遞機制是為了多個線程并發(fā)更新UI的同時，保證線程安全；

一、Handler 與 sleep

public class HandlerAndSleep {

    // 1、定義一個Handler類，用于處理接受到的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、新建一個實現(xiàn)Runnable接口的線程類
    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、在需要啟動線程的地方加入下面語句,啟動線程后，線程每10s發(fā)送一次消息
        new Thread(new MyThread()).start();
    }
}

結果打印如下：

2022-05-30 11:30:42.320 17864-17864/com.yh.study D/HandlerAndSleep: HandlerAndSleep
2022-05-30 11:30:52.324 17864-17864/com.yh.study D/HandlerAndSleep: HandlerAndSleep
2022-05-30 11:31:02.326 17864-17864/com.yh.study D/HandlerAndSleep: HandlerAndSleep
2022-05-30 11:31:12.335 17864-17864/com.yh.study D/HandlerAndSleep: HandlerAndSleep
2022-05-30 11:31:22.338 17864-17864/com.yh.study D/HandlerAndSleep: HandlerAndSleep
2022-05-30 11:31:32.339 17864-17864/com.yh.study D/HandlerAndSleep: HandlerAndSleep
2022-05-30 11:31:42.347 17864-17864/com.yh.study D/HandlerAndSleep: HandlerAndSleep

二、Handler 與 postDelayed

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() {
    	// 開啟定時器
        handler.postDelayed(runnable, 2000);
		// 停止定時器
//        handler.removeCallbacks(runnable);
    }
}

結果打印如下：

2022-05-30 14:32:41.533 24351-24351/com.yh.study D/HandleAndPostDelayed: HandleAndPostDelayed
2022-05-30 14:32:43.534 24351-24351/com.yh.study D/HandleAndPostDelayed: HandleAndPostDelayed
2022-05-30 14:32:45.537 24351-24351/com.yh.study D/HandleAndPostDelayed: HandleAndPostDelayed
2022-05-30 14:32:47.539 24351-24351/com.yh.study D/HandleAndPostDelayed: HandleAndPostDelayed
2022-05-30 14:32:49.546 24351-24351/com.yh.study D/HandleAndPostDelayed: HandleAndPostDelayed
2022-05-30 14:32:51.550 24351-24351/com.yh.study D/HandleAndPostDelayed: HandleAndPostDelayed

三、Handler 與 timer

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);
            }
        };
        //啟動定時器 參數(shù)對應為 TimerTask 延遲時間 間隔時間
        timer.schedule(task, 2000, 2000);
    }
}

結果打印如下：

2022-05-30 14:43:40.922 25052-25052/com.yh.study D/HandlerAndTimer: HandlerAndTimer
2022-05-30 14:43:42.924 25052-25052/com.yh.study D/HandlerAndTimer: HandlerAndTimer
2022-05-30 14:43:44.925 25052-25052/com.yh.study D/HandlerAndTimer: HandlerAndTimer
2022-05-30 14:43:46.926 25052-25052/com.yh.study D/HandlerAndTimer: HandlerAndTimer
2022-05-30 14:43:48.927 25052-25052/com.yh.study D/HandlerAndTimer: HandlerAndTimer

在Android上常用的定時器有兩種，一種是Java.util.Timer，一種就是系統(tǒng)的AlarmService。

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);
    }
}

以下結論來源其他博主

（小子在驗證過程中，連接usb情況正常，拔掉usb后與結論不符，可能是小子哪里寫的有問題）

在Timer中，當連接USB線進行調試時，會發(fā)現(xiàn)一切工作正常，每5秒更新一次界面，即使是按下電源鍵，仍然會5秒觸發(fā)一次。當拔掉USB線，按下電源鍵關閉屏幕后，過一段時間再打開，發(fā)現(xiàn)定時器明顯沒有繼續(xù)計數(shù)，停留在了關閉電源鍵時的數(shù)字。
在AlarmService中，拔掉USB線，按下電源鍵，過一點時間再次打開屏幕，發(fā)現(xiàn)定時器一直在計數(shù)。

測試機型小米8,上timer，下AlarmService

補充：采用Handler與timer及TimerTask結合的方法

1. 定義定時器、定時器任務及Handler句柄

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);
    }
};

2. 初始化計時器任務

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

3. 啟動定時器

timer.schedule(task, 2000, 2000);

總結?

原文鏈接：https://blog.csdn.net/Twan1234/article/details/125050488

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網(wǎng)站首頁編程語言正文

Android常用定時器的實現(xiàn)方式_Android

目錄

前言

一、Handler 與 sleep

二、Handler 與 postDelayed

三、Handler 與 timer

以下結論來源其他博主

補充：采用Handler與timer及TimerTask結合的方法

總結?

相關推薦

日本免费高清视频-国产福利视频导航-黄色在线播放国产-天天操天天操天天操天天操|www.shdianci.com

網(wǎng)站首頁 編程語言 正文

Android常用定時器的實現(xiàn)方式_Android

目錄

前言

一、Handler 與 sleep

二、Handler 與 postDelayed

三、Handler 與 timer

以下結論來源其他博主

補充：采用Handler與timer及TimerTask結合的方法

總結?

相關推薦

網(wǎng)站首頁編程語言正文