与ONE_SHOT标志待定意图 [英] Pending intent with ONE_SHOT flag

问题描述

目前我已经有了这个code：

Currently I've got this code:

public static void setupAlarm(Context context) {
        Intent myIntent = new Intent(context, Receiver.class);

        PendingIntent pendingIntent = PendingIntent.getBroadcast(context,
                0, myIntent, PendingIntent.FLAG_NO_CREATE);
        if (pendingIntent != null) {
            return;
        } else {
            pendingIntent = PendingIntent.getBroadcast(context, PENDING_INTENT_RETRY, myIntent,
                    PendingIntent.FLAG_ONE_SHOT);
        }

        AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
        Calendar calendar = Calendar.getInstance();
        calendar.setTimeInMillis(System.currentTimeMillis());
        calendar.add(Calendar.MINUTE, 2);
        alarmManager.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);
    }

我要的是使用一个时间待定意图和等待火灾。如果在此期间，有人问新的报警，如果报警存在，我不希望任何设置。现在我的问题：第一次报警后，挂起的意图是由于ONE_SHOT标志删除，但我可以再和不创建挂起的意图

What I want is to use pending intent one time and wait for the fire. If in the meantime someone asks for a new alarm, if the alarm exist I don't want to setup anything. Now my question: after the first alarm, the pending intent is deleted due to the ONE_SHOT flag, but can I create the pending intent again or not?

推荐答案

是的，当然你可以重新创建它。你会得到不同的的PendingIntent 从第一个。

Yes, of course you can create it again. You will get a different PendingIntent from the first one.

不过，也有与您发布的code一些问题。首先，创建的PendingIntent 是这样的：

However, there are a few problems with the code you've posted. First of all, you create the PendingIntent like this:

    pendingIntent = PendingIntent.getBroadcast(context,
            PENDING_INTENT_RETRY, myIntent, PendingIntent.FLAG_ONE_SHOT);

但你检查它是否存在这样的：

but you check if it exists like this:

    pendingIntent = PendingIntent.getBroadcast(context,
            0, myIntent, PendingIntent.FLAG_NO_CREATE);

这将检查始终返回null ，因为你使用的是不同的请求code ！当您创建的PendingIntent 你通过 PENDING_INTENT_RETRY 为请求code ，但是当你检查它是否存在你传递0作为请求code 。

This check will always return null because you are using a different requestCode! When you create the PendingIntent you pass PENDING_INTENT_RETRY as requestCode, but when you check if it exists you pass 0 as requestCode.

第二个问题是 FLAG_ONE_SHOT 的工作方式。如果您创建一个的PendingIntent 使用 FLAG_ONE_SHOT ，然后尝试得到一个的PendingIntent 使用 FLAG_NO_CREATE ，将始终返回null，即使的PendingIntent 尚未使用！由于此行为，则不能使用 FLAG_NO_CREATE ，以确定是否报警等待如果您已设置使用警报的的PendingIntent 与 FLAG_ONE_SHOT 创建。

The second problem is the way FLAG_ONE_SHOT works. If you create a PendingIntent using FLAG_ONE_SHOT and then try to get a PendingIntent using FLAG_NO_CREATE, it will always return null, even if the PendingIntent has not yet been used! Because of this behaviour, you cannot use FLAG_NO_CREATE to determine if an alarm is pending, if you have set that alarm using a PendingIntent created with FLAG_ONE_SHOT.

如果你真的想用这个架构，那么你就不能使用 FLAG_ONE_SHOT 。刚刚创建的PendingIntent （通常不旗），并使用检查其存在 FLAG_NO_CREATE 。

If you really want to use this architecture, then you cannot use FLAG_ONE_SHOT. Just create the PendingIntent normally (without flags) and check for its existence using FLAG_NO_CREATE.

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