AlarmManager 执行任务过于频繁

Question

该功能的目标是执行一项任务，将应用程序数据库的所有条目中的值设置为 0。该任务应该在每天午夜执行（或者 phone 在当天第一次被唤醒（如果我理解 AlarmManager.RTC 正确的话））。问题是任务每天执行几次而不是只执行一次。

在 MainActivity 的 onCreate 中：

// Calendar with timestamp midnight
    Calendar calendar = Calendar.getInstance();
    calendar.set(Calendar.HOUR_OF_DAY, 0);
    calendar.set(Calendar.MINUTE, 0);
    calendar.set(Calendar.SECOND, 0);

// initiate Alarm to reset commits @ midnight
    Intent intent = new Intent(this, AlarmReceiver.class);
    PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 100, intent, 0);
    AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
    alarmManager.setRepeating(AlarmManager.RTC, calendar.getTimeInMillis(),AlarmManager.INTERVAL_DAY, pendingIntent);

包含执行代码的class：

public class AlarmReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent)
    {
        ContentValues APValues = new ContentValues();
        APValues.put(APEntry.AP_DAILY_COMMIT, 0);

        int rowsUpdated = context.getContentResolver().update(APEntry.CONTENT_URI, APValues, null, null);
        if (rowsUpdated == 0) {
            Toast.makeText(context, "Resetting commits failed!", Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(context, "Reset commits successful!", Toast.LENGTH_SHORT).show();
        }
    }
}

Answer 1

我不明白为什么你的闹钟被叫了多次。我可以假设您可能多次设置闹钟。您可以使用 SharedPreferences 来检查是否已过去 1 天。因此，您的代码可能如下所示：

public class AlarmReceiver extends BroadcastReceiver
{
    @Override
    public void onReceive(Context context, Intent intent)
    {
        if (dayElapsed(context))
        {
            ContentValues APValues = new ContentValues();
            APValues.put(APEntry.AP_DAILY_COMMIT, 0);

            int rowsUpdated = context.getContentResolver().update(APEntry.CONTENT_URI, APValues, null, null);
            if (rowsUpdated == 0)
            {
                Toast.makeText(context, "Resetting commits failed!", Toast.LENGTH_SHORT).show();
            }
            else
            {
                Toast.makeText(context, "Reset commits successful!", Toast.LENGTH_SHORT).show();
            }
        }
    }

    private boolean dayElapsed(Context context)
    {
        String lastUpdateTimeKey = "dayElapsed";
        SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(context);
        long lastUpdateTime = sharedPrefs.getLong(lastUpdateTimeKey, -1);
        long currentMillis = System.currentTimeMillis();
        long oneDayMillis = TimeUnit.DAYS.toMillis(1);
        long timeElapsed = currentMillis - lastUpdateTime;

        if (lastUpdateTime < 0 || timeElapsed >= oneDayMillis)
        {
            SharedPreferences.Editor editor = sharedPrefs.edit();
            editor.putLong(lastUpdateTimeKey, currentMillis);
            editor.commit();

            return true;
        }

        return false;
    }
}

AlarmManager 执行任务过于频繁

AlarmManager executing task too often

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