Clearing app data and cache when releasing new update

Question

I am releasing a new update, that will change my app build completely from the last version. I want the the app to be fresh and delete all old unceccery cache and data for current users. How can I achieve this? what the right code to use, and where to add it exactly, I am not expert in android development, so please guide me more specifically. I checked this question, but there's no mention of what code actually works to clear data and cache.

My setup (incase needed):

// Android Studio 3.0        
compileSdkVersion 26
buildToolsVersion '27.0.3' (Gradle)
minSdkVersion 16
targetSdkVersion 26

score 1 · Answer 1 · answered Sep 10 '18 at 20:34

1

You can listen to event in a bordcast receiver class, when your application is updated & do the cleanup in onReceive of your broadcast receiver.

The following comment in the link you shared :) has all the details.

https://stackoverflow.com/a/48520332/8312634

answered Sep 10 '18 at 20:34

N0000B

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Will it work even if I didn't declare a reciver in my previous version? And whats the proper method to clear data and cache? That's my biggest concern. – Kash Sep 10 '18 at 20:47
I believe you'll get this event after the application is updated, not before. So you can have the cleaup code executed on that event. Also, what do you mean by data & cache? If its a file, you'll need to delete them, or if its something like sharedprefs, you can clear them like so https://developer.android.com/reference/android/content/SharedPreferences.Editor.html#clear() – N0000B Sep 10 '18 at 20:49
The old version uses Webview the cache and data are related to the Webview. – Kash Sep 10 '18 at 20:56
Try this to clear cache of WebView: https://developer.android.com/reference/android/webkit/WebView#clearCache%28boolean%29 – N0000B Sep 10 '18 at 21:01

score 0 · Accepted Answer · answered Sep 12 '18 at 07:43

Adding this to my MainActivity is what worked for me to clear cache and data.

   @Override
   protected void onDestroy() {
      super.onDestroy();
      try {
         trimCache(this);
      } catch (Exception e) {
         // TODO Auto-generated catch block
         e.printStackTrace();
      }
   }

   public static void trimCache(Context context) {
      try {
         File dir = context.getCacheDir();
         if (dir != null && dir.isDirectory()) {
            deleteDir(dir);
         }
      } catch (Exception e) {
         // TODO: handle exception
      }
   }

   public static boolean deleteDir(File dir) {
      if (dir != null && dir.isDirectory()) {
         String[] children = dir.list();
         for (int i = 0; i < children.length; i++) {
            boolean success = deleteDir(new File(dir, children[i]));
            if (!success) {
               return false;
            }
         }
      }

      // The directory is now empty so delete it
      return dir.delete();
   }

}

Answer found here: Clear Application cache on exit in android.

Now cache is cleared every time, a user closes the app, it works for me since I don't want to keep cache from webview, for others who want to clear this on updates only, implementing this with onReceive should work.

Clearing app data and cache when releasing new update

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