安卓筆記俠

@Override
    public void onCreate() {
        super.onCreate();
        //設定一個PendingIntent，來表示點擊通知欄時跳轉到哪里
        PendingIntent contentIntent = PendingIntent.getActivity(this, 0, new Intent(this, MainActivity.class), 0);
        Notification.Builder builder = new Notification.Builder(this);
        //建立一個notificationManager來管理通知的出現
        notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
        //構造通知的樣式，包括圖片，標題，內容，時間。
        builder.setSmallIcon(R.mipmap.ic_launcher).
                setWhen(System.currentTimeMillis()).
                setContentTitle("我是標題").
                setContentText("我是內容").
                setTicker("在啟動時彈出一個消息").//這個Android5.0以上可能會失效
                setWhen(System.currentTimeMillis()).
                setContentIntent(contentIntent);
                //最后通過build建立好通知
        Notification notification = builder.build();
        //通過manager來顯示通知，這個1為notification的id
        notificationManager.notify(1,notification);
        //啟動為前臺服務,這個1為notification的id
        startForeground(1,notification);
    }

AlarmManager manager = (AlarmManager) getSystemService(ALARM_SERVICE);

int time = 1000;
        long triggerAtTime = SystemClock.elapsedRealtime() + time;
        Intent i = new Intent(this,AlarmReceiver.class);
        PendingIntent pi = PendingIntent.getBroadcast(this, 0, i, 0);
        manager.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, triggerAtTime, pi);

@Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        new Thread(new Runnable() {
            @Override
            public void run() {
               //執行想做的操作，比如輸出時間
            }
        }).start();
          //步驟二里面的代碼
        return super.onStartCommand(intent, flags, startId);
    }

public class AlarmReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        Intent i = new Intent(context,LongRunningService.class);
        context.startService(i);
    }
}