在 Android 5 秒后触发警报

Question

我想在 android 的 5 秒后触发警报，但它不起作用。它在 1 分钟而不是 5 秒后触发。为什么？

@Override
public void onReceive(Context context, Intent intent) {
    PowerManager powerManager=(PowerManager)context.getSystemService(Context.POWER_SERVICE);

    PowerManager.WakeLock wakeLock= powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,"Power Manager");

    wakeLock.acquire();
    showNotification("Wake up. Alarm Triggered",context);
}
public void showNotification(String message ,Context context)
{
    Toast.makeText(context, message, Toast.LENGTH_SHORT).show();
}

public void setAlarm(Context context)
{
    Calendar calendar= Calendar.getInstance();
    AlarmManager alarmManager=(AlarmManager) context.getSystemService(Context.ALARM_SERVICE);

    Intent intent=new Intent(context, Alarm.class);
    PendingIntent pendingIntent= PendingIntent.getBroadcast(context,0,intent,0);

    alarmManager.setRepeating(AlarmManager.RTC, calendar.getTimeInMillis(),5000,pendingIntent);

}

}

Answer 1

引用自the docs：

Note: Beginning with API 19 (KITKAT) alarm delivery is inexact: the OS will shift alarms in order to minimize wakeups and battery use. There are new APIs to support applications which need strict delivery guarantees; see setWindow(int, long, long, PendingIntent) and setExact(int, long, PendingIntent).

如果您想在您的应用处于运行时执行某些操作（我认为间隔 5 秒），请使用 Handler:

Note: The Alarm Manager is intended for cases where you want to have your application code run at a specific time, even if your application is not currently running. For normal timing operations (ticks, timeouts, etc) it is easier and much more efficient to use Handler.

特别是，postDelayed 或 sendMessageDelayed 可能是您申请的正确选择（但是，由于您没有告诉我们您的主要 objective，这只是猜测）。

Answer 2

Praviin，如果你想在 5 秒后触发某些东西，只需使用如下处理程序即可。您不需要将 alarmManager 代码放入处理程序中。

final Handler handler = new Handler();
                        handler.postDelayed(new Runnable() {
                            @Override
                            public void run() {

                                //The code here will run after 5 sec, do what you want

                            }
                        }, 5*1000);

在 Android 5 秒后触发警报

Make alarm trigger after 5 sec in Android

android

android-alarms