Android 重复警报，每次打开时覆盖自我

Question

我有以下警报，在应用程序启动时从 MainActivity 获取运行。我想我已将其编程为在每次启动新应用程序时覆盖自身。但我发现很难测试。这是否确实会覆盖自身，或者如果我多次关闭和打开应用程序，我会收到很多警报吗？

如何测试我创建了多少个警报？

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Intent intent = new Intent(this, AlarmBroadcastReceiver.class);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);

        AlarmManager manager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
        manager.setRepeating(AlarmManager.RTC_WAKEUP, 5000, 60000, pendingIntent);
    }

因此 PendingIntent.getBroadcast(Context context, int requestCode, Intent intent, int flags)

requestCode是？（我假设为警报设置一个 ID，您可以用新警报覆盖它）
flags干什么？（告诉闹钟如果新的闹钟ID相同怎么办？）

Answer 1

是的，您覆盖了它，因为每次创建 activity 时您都使用相同的请求代码。 requestcode 是 PendingIntent.getBrodacast() 方法的第二个参数，其操作类似于您的 id 警报以稍后更新它（例如取消它）。您可以使用此代码检查您的闹钟是否已设置：

boolean alarmUp = (PendingIntent.getBroadcast(context, 0, 
        new Intent("com.my.package.MY_UNIQUE_ACTION"), 
        PendingIntent.FLAG_NO_CREATE) != null);

但是您没有使用代码设置闹钟，您需要调用：

AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
alarmManager.set(AlarmManager.RTC_WAKEUP, 0 ,pendingIntent);

实际设置闹钟。

关于您的最后一个问题，您可以通过多种方式使用标志：

int FLAG_CANCEL_CURRENT Flag indicating that if the described PendingIntent already exists, the current one should be canceled before generating a new one.

int FLAG_IMMUTABLE Flag indicating that the created PendingIntent should be immutable.

int FLAG_NO_CREATE Flag> indicating that if the described PendingIntent does not already exist, then simply return null instead of creating it.

int FLAG_ONE_SHOT Flag indicating that this PendingIntent can be used only once.

int FLAG_UPDATE_CURRENT Flag indicating that if the described PendingIntent already exists, then keep it but replace its extra data with what is in this new Intent.

Answer 2

您可以通过以下方式在 Android 中设置特定时间的闹钟：

Intent intent = new Intent(context, AlarmService.class);
final int _id = Integer.parseInt(""+MCZManagers.timeToMillies(alarmTime));
    PendingIntent pendingIntent = PendingIntent.getBroadcast(context, _id, intent, 0);
    AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
    alarmManager.set(AlarmManager.RTC_WAKEUP, MCZManagers.dateTimeToMillies(alarmDateTime), pendingIntent);

一旦你销毁应用程序，闹钟也会被销毁，不再播放。

Android 重复警报，每次打开时覆盖自我

Android repeating alarm, override self on each open

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android-alarms