Android Context Change on update?

Question

I have a Native Android App in the Store. This App has its Settings stored in the SharedPreferences. Now I am working on an Update for the App. The Update is a Xamarin Cross-Platform App. App Name, Package Name, and those things are the same as in the Native App. But I can't get the values from SharedPreferences now. Did I make something wrong? I guess it's because of a different Application Context. But I don't know why.

Here is how the Native App is loading the Values:

final SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
final Set<String> keySet = prefs.getAll().keySet();

for (final String key : keySet) {
    if (key.startsWith(DatabaseSetting.DATABASE_SETTING_KEY_PREFIX)) {
        //Do stuff
    }
}

After updating the App I can not see any keys in the prefs. C# Xamarin Code to also load these prefs:

ISharedPreferences sharedPrefs = PreferenceManager.GetDefaultSharedPreferences(Application.Context);
foreach (string key in sharedPrefs.All.Keys)
{
  if(key.StartsWith(DATABASE_SETTING_KEY_PREFIX))
}

The App was updated without uninstalling the old one. Just deployed the new one.

I install the App from store and then just start debugging the new one. The old gets replaced automatically. — M.D., Mar 12 '18 at 07:20
By `start debugging`, you mean click the green triangle button in visual studio under debug mode? — Elvis Xia - MSFT, Mar 12 '18 at 07:24
I found out, that Android is removing the old App first, so the data is lost before the new app is starting. How can I simulate a real update process without removing the prefs? — M.D., Mar 13 '18 at 15:25
visual studio will detect the installed app with the same packageName. And uninstall the existing App, if the previous app is different from the to be installed one. You can take a try to generate an APK file in VS and use `adb install -r` to try to update that app. — Elvis Xia - MSFT, Mar 14 '18 at 07:49
Okay, strange. I will try that. But the iOS update was possible from VS. — M.D., Mar 14 '18 at 08:06
Tried it. But update fails every time. APK is damaged. But when the old is not installed it can install the APK — M.D., Mar 14 '18 at 08:35
Then there will be no way to update from android native app to Xamarin.Android directly. — Elvis Xia - MSFT, Mar 14 '18 at 08:38
I'm not sure of that, never tried that. Google Store will be responsible of install/uninstalling of your app at that time. You can have a try if it is possible. — Elvis Xia - MSFT, Mar 14 '18 at 09:04

score 0 · Answer 1 · answered Mar 09 '18 at 11:01

0

Is it giving you a nullpoint?
Are you storing app context (Android.App.Application.Context) or class context(Context)?
Are there any other exceptions thrown that you possibly aren't catching?

answered Mar 09 '18 at 11:01

Thabiso Motswagole

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It's giving me just empty SharedPreferences. No Exceptions. Application.Context – M.D. Mar 09 '18 at 11:33
@M.D. I'd suggest you check where you are passing the shared preference... if possible edit your question and add the point you are passing the shared preference – Thabiso Motswagole Mar 09 '18 at 11:42
1

@M.D. ok try to see what this user did [here](https://stackoverflow.com/a/10786739/5251647) and see how they do it... i think that will help – Thabiso Motswagole Mar 09 '18 at 12:18
Good point. But unfortunately I can not change the "old" Apps code. So I can not change the way it is saved. – M.D. Mar 09 '18 at 12:37
@M.D. ok that makes it difficult... sorry I couldn't be of assistance – Thabiso Motswagole Mar 09 '18 at 12:43

Android Context Change on update?

1 Answers1