Android Detect clear data for refreshing widget

Question

Is there any way to know in "real-time", via broadcast I guess, when a user has cleared data of the app?

I have a widget showing some user details, which are stored in the Preferences, but when the user clear the app data, I am not able to know it until the next refresh/update (the onUpdate() call) which is every 30min.

During that time, the widget is showing useless values. So I need to trigger somehow any broadcast to capture it from a receiver and update the widget when that happens.

Is that possible?

the problem is not a app, is a widget which is already in the homescreen — nsL, Sep 16 '14 at 16:55

score 3 · Answer 1 · edited May 23 '17 at 11:53

3

Looks like there is no way to get an event for that. The app's process should be terminated after clearing data. https://stackoverflow.com/a/10701338/450243

edited May 23 '17 at 11:53

Community

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answered Sep 18 '14 at 20:08

Chris Arriola

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score 3 · Answer 2 · answered Sep 24 '14 at 04:02

3

You can use a service that implements a http://developer.android.com/reference/java/util/prefs/PreferenceChangeListener.html to monitor when your preferences change.

Even if the service is killed by the system, if you use START_STICKY it will be brought to live, and you'll be able to determine if your keys are available or has been deleted. I've used this approach in a couple of apps and it works like a charm.

If you want to make even more efficient, you can add a receiver for screen on/off, so you can start your service only when the screen starts and terminate your service when the screen gets on.

Hope it helps.

answered Sep 24 '14 at 04:02

Junior Buckeridge

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but is that working/being triggered when the user clear data of the app? – nsL Sep 24 '14 at 13:56
If the user clears the data of the app (and this last one is not stopped) yes, it's triggered. In case the system decides to stop/start your service, it's pretty straightforward detecting if your preferences contains any key inside **Service.onStart(...)**, so either way it will work. – Junior Buckeridge Sep 24 '14 at 15:28

score 1 · Answer 3 · answered Nov 29 '17 at 14:48

You can also have a look at this solution, you will not exactly get a callback but you will get a fighting chance to update your widget before clearing the data

android:manageSpaceActivity=".path.to.MyActivity"

This will replace the button "Clear Data" from the settings to "Manage Space". Now you can redirect the user to a custom activity that is controlled by you.

The launch of the activity will act as callback for you. Manipulate your data in your activity and use the following code

private void clearPreferences() {
    try {
        // clearing app data
        Runtime runtime = Runtime.getRuntime();
        runtime.exec("pm clear YOUR_APP_PACKAGE_GOES HERE");

    } catch (Exception e) {
        e.printStackTrace();
     }
   }

to clear the app data.

Android Detect clear data for refreshing widget

3 Answers3