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Android: changing SharedPreferences of another application

I am trying to write an application that should read, modify and save some parameters in the general preferences of another application ( data/data/package_name/shared_prefs/file.xml ).

This application is not mine, and I have a root device for testing.

What android permissions should I add to the manifest and how can I access this file and change it? I know that SharedPreferences unique for each application / APK, but I need to change it in root mode.

I have working code to change the xml file on the SD card, but when I change the path to "data/data/package_name/shared_prefs/file.xml" , it gives me an exception and a message

 android open failed eacces (permission denied)

Is there any way I can achieve this?

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4 answers

Take a look at this answer:

fooobar.com/questions/375202 / ...

When you use su, you will have permission to change what you want on the file system.

However, I agree with Chris that it is not very pleasant to do what you want.

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To answer your question, if you have a root, you can do it with reflection. I did it on android 4.1, on other platforms it may work differently. It’s good that the general settings are not available only to system services, so you can access the “hidden” methods through reflection. Put this in a try-catch:

 Process proc = Runtime.getRuntime().exec(new String[] { "su", "-c", "chmod 777 /data/data/package_name/shared_prefs/package_name_preferences.xml" }); proc.waitFor(); proc = Runtime.getRuntime().exec(new String[] { "su", "-c", "chmod 777 /data/data/package_name/shared_prefs" }); proc.waitFor(); proc = Runtime.getRuntime().exec(new String[] { "su", "-c", "chmod 777 /data/data/package_name" }); proc.waitFor(); File preffile = new File("/data/data/package_name/shared_prefs/package_name_preferences.xml"); Class prefimplclass = Class.forName("android.app.SharedPreferencesImpl"); Constructor prefimplconstructor = prefimplclass.getDeclaredConstructor(File.class,int.class); prefimplconstructor.setAccessible(true); Object prefimpl = prefimplconstructor.newInstance(preffile,Context.MODE_WORLD_READABLE | Context.MODE_WORLD_WRITEABLE); Editor editor = (Editor) prefimplclass.getMethod("edit").invoke(prefimpl); //put your settings here editor.commit();
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If you do not own another application, you should not do this. The only way without root would be to be readable in a world that depreciates and is almost never used.

I doubt that someone will give you the answer you need if you do not indicate why you need access.

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You should not change the preferences of another application, root or not.

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