Which Android Intent Flags to Use

Question

I have an application which receives a broadcast from the `AlarmManager`. Upon this, it starts a transparent `Activity` (`AlarmAlertDialogActivity`) which then shows an `AlertDialog`. Clicking cancel on the `AlertDialog` result in a call to `finish()`. As the `AlarmAlertDialogActivity` is not launched from another `Activity` but a broadcast receiver, it is launched with ``` Intent.FLAG_ACTIVITY_NEW_TASK ``` This means the Activity will be launched in a new task. My problem is that when the app is relaunched from recent history after cancelling the `AlertDialog` (i.e. by holding the home button and clicking the app's icon) the AlertDialog is relaunched. I had hoped by using `finish()`/`Intent` flags I would be able to avoid this; what I would like to happen is the last `Activity` before the `AlertDialog`'s parent Activity to be launched. I have tried bitmasking `Intent.FLAG_ACTIVITY_NO_HISTORY` as an additional flag when launching `AlarmAlertDialogActivity` but this appears to make no…

Accepted Answer

I did something similar in another project. I had a BroadcastReceiver that got information about data connectivity and SIM-Profile changes and showed a dialog (using an activity like yours) warning the user that he might incur charges. What I ended up doing was the following:

In the manifest, in the `<Activity>` tag for your AlarmAlertDialogActivity, add the following:

```
android:excludeFromRecents="true"
android:noHistory="true"
android:taskAffinity=""
```

Explanation: setting `excludeFromRecents` and `noHistory` to "true" ensure that the activity won't show up in the list of recent applications and also that once the user navigates away from it he won't be able to go back there (which is probably what you want). Setting `taskAffinity` to the empty string ensures that AlarmAlertDialogActivity will be run in it's own task even if your application is running when your dialog is shown.

As long as you have another activity that functions as the main activity of your application (ie: with intent filters for `action.MAIN` and `category.LAUNCHER`) this should solve your problem.

Which Android Intent Flags to Use

Solution

Problem