SharedPreferences lost after app update

Question

I've been researching this issue for the whole day. Here are key points:

SharedPreferences should be persistent when user does app update
in my case, after updating the app, they are lost
the issue is reproducable every time (I install old APK from Play Store and then adb install -r new.apk with the new (updated, signed, versionCode incremented) APK)

8 hours later

For test I changed SharedPrefs filename in new.apk (SP2.xml) and upon updating, the old SharedPrefs file from old.apk (SP.xml) got deleted! Here is adb shell output:

adb install old.apk
adb shell "su -c 'ls /data/data/com.pkg.name/shared_prefs'": CRC.xml
adb install -r new.apk
adb shell "su -c 'ls /data/data/com.pkg.name/shared_prefs'": CRC2.xml (CRC.xml missing!)

My SharedPreferences singleton class (init: SharedPrefs.init(getApplicationContext());):

public final class SharedPrefs {
    private static SharedPrefs sp;

    private SharedPrefs() {
    }

    public static void init(Context context) {
        if (sp == null)
            sp = context.getSharedPreferences("CRC2", Context.MODE_PRIVATE);
    }

    public static void saveString(String name, String value) {
        sp.edit().putString(name, value).apply();
    }

    public static String getString(String key, String defaultValue) {
      sp.getString(key, defaultValue);
    }
    ...
}

So basically I am loosing SharedPreferences and I have no clue why. Please help, any hint welcome!

is your app package name is same as previous? or you saving a serialized model class as string in shared preference? — Abhishek Singh, Jul 02 '18 at 11:51
Yes, package name is the same (otherwise I won't be able to update the app on Play Store). I have, however, changed the ``s `android:label` (the name of the app). — c0dehunter, Jul 02 '18 at 11:53
Are you saving a serialized model class as string in shared preference? — Abhishek Singh, Jul 02 '18 at 11:57
What does your code look like which retrieves the Shared Preference object? — Zun, Jul 02 '18 at 11:58
Try installing the application from your android studio and it will show you a dialog that it will uninstall the existing application. Just try it and you'll see the error message. — Daksh Gargas, Jul 02 '18 at 12:07
Few things. Why are you installing manually through adb? Secondly try this: `adb uninstall -k com.zun` and then `adb install com.zun` obv set the correct package name there. — Zun, Jul 02 '18 at 21:08
May have a look at my question and their answers: https://stackoverflow.com/q/12637737/1306012 — Bruno Bieri, Jul 05 '18 at 08:33

user3407133 · Accepted Answer · 2018-07-06T04:34:44.443

12

If you changed a property in the application section of the manifest file, this error will occur and 90% of the time, the shared pref data will be reset. This is what I found from my test installing the signed apk on top of my play store app. Not sure what will happen if the app was installed from the play store as an update, but am pretty sure the data would be lost in that case as well.

EDIT- I republished the application and tested multiple times. This in fact is the issue.

edited Jul 06 '18 at 04:34

answered Jul 04 '18 at 06:02

user3407133

156
1
3

This should be a comment, not an answer considering it's not based on facts and lots of uncertainty. – Zun Jul 05 '18 at 08:18
5

I published on the play store and verified this. I have confirmed it today. Also, considering almost no one else has pointed this out, thought it was important to highlight it. Took me a long time to figure it out – user3407133 Jul 06 '18 at 04:34
1

Worked for me. You saved my day man, I was going insane. My application keeps offline data, and I was losing everything after updating to SDK 28. – salezica Sep 27 '19 at 18:09
1

How do you keep the error from happening? I have manifest data that needs to change with the update. – Malachi Holden Nov 10 '20 at 20:06
1

This is so bizarre and it's not documented anywhere! It's mind bogling! To avoid this, I think JetPack's new DataStore might be a good solution. Although you would have to encrypt the data yourself (and it's currently in alpha). – Takeshi Kaga Apr 06 '21 at 17:24
Is there a way to fix it? – Rohit Singh Jan 12 '23 at 22:18

SharedPreferences lost after app update

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