CODEWITHSUNDEEP
androidsharedpreferences
l33t
l33t

Reputation: 19937

How to read other app's SharedPreferences (same user ID)?

Tested on Android 4.3. I have two apps, com.my.app.first and com.my.app.second. In my activity I want to read preferences from the other app. I chose to use the same user ID for both my apps:

android:sharedUserId="com.my.app"

I always load my preferences like this:

prefs = getSharedPreferences("MyAppPreferences", Context.MODE_PRIVATE);

Now, in my second app I do the following:

try {
    Context context = createPackageContext("com.my.app.first", Context.CONTEXT_IGNORE_SECURITY);
    // context.getPackageName() does indeed return "com.my.app.first"

    // Note: Context.MODE_WORLD_READABLE makes no difference here!
    prefs = context.getSharedPreferences("MyAppPreferences", Context.MODE_PRIVATE);
}

prefs.mFile erroneously points to /data/data/com.my.app.second/shared_prefs/MyAppPreferences.xml.

Obviously, the call to getSharedPreferences returns the preferences for the current app even though I used the context of the other app. What am I doing wrong? Please help!

Upvotes: 7

Views: 6763

Answers (4)

topGun1028
topGun1028

Reputation: 21

Since both your apps are running you can also solve this problem by setting shared preferences:

tempContext.getSharedPreferences("sharedInformation", Context.MODE_MULTI_PROCESS);

Upvotes: 0

user3454585
user3454585

Reputation: 39

Solved by just reading the old context again. Sounds like a cache to me too.

Context tempContext = context.createPackageContext(originalContext.getPackageName(),Context.CONTEXT_IGNORE_SECURITY);
SharedPreferences sharedInformationM2 = tempContext.getSharedPreferences("sharedInformation", Context.MODE_WORLD_READABLE);

Upvotes: 2

l33t
l33t

Reputation: 19937

Found the problem! This sure looks like a bug in the getSharedPreferences API. It turned out that a previous call to getSharedPreferences caused the other context.getSharedPreferences() call to return the previous instance - the current app's preferences.

The solution was to make sure that getSharedPreferences() was NOT called before reading the preferences of the other app.

Upvotes: 2

stack_ved
stack_ved

Reputation: 721

You might want to make the SharedPreference created in App A MODE_WORLD_READABLE and use a common sharedUserId for both App A and App B. Like mentioned in the link,

http://androiddhamu.blogspot.in/2012/03/share-data-across-application-in.html

Upvotes: 1

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