xamarin.android - how to get access to read and write sqlite db file from shared context?

Question

I share my .db sqlite file between two aplications.

I succesful shared this file ( because second application can see it ) and just cant use it. I guess that is because of security reasons.

This is how I done sharing:

SharedUserId is same for both apps
simply creation of database

var Folder = System.Environment.GetFolderPath(System.Environment.SpecialFolder.Personal);

using (var conn = new SQLiteConnection(System.IO.Path.Combine(Folder, "Paczki.db")))
{
    conn.CreateTable<Odczyt>();
    return true;
};

Receiving shared context.

Context sharedContext = null;

try
{
    sharedContext = 
        this.CreatePackageContext(
            "MobilnePaczki.MobilnePaczki", PackageContextFlags.IgnoreSecurity);

}
catch (Exception e)
{
}

using (var conn = 
    new SQLiteConnection(sharedContext.DataDir.ToString() + "/files/Paczki.db")) //I am sure that file exists
//... Could not open database file: ... files/Paczki.db (CannotOpen)

What I tried:

change PackageContextFlags.IgnoreSecurity to PackageContextFlags.IncludeCode .. But then sharedContext = null
Copy .db file to second app and then connect to it, then I get an UnauthorizedAccessException

From other threads like this and I can see that it is possible to use db file from other application.

Do you have any idea what can i do in such a problem?

UPDATE

Thanks to Billy's answer I found out that I declared my SharedUserId in <application> tag in AnfroidManifest.xml. The correct way is to declare it in <manifest> tag..

<manifest (...) android:sharedUserId="App.Id">

After I changed it I got INSTALL_FAILED_UID_CHANGED Error when I was installing application. To fix this I used:

adb shell rm -rf /data/data/appname.appname

score 1 · Accepted Answer · answered Mar 23 '18 at 08:33

1

I have tested your code, it works. Did you create the database before you set the sharedUserId? When I test this scenario, I meet this problem. If so, uninstall and reinstall the app could solve this problem.

answered Mar 23 '18 at 08:33

Billy Liu - MSFT

2,168
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sharedUserID is declared in the AndroidManifest file, so database is created after setting the sharedUserId. – Grzegorz G. Mar 23 '18 at 09:15
did you successfully connect to database in second application (did u try insert or select rows?) – Grzegorz G. Mar 23 '18 at 09:16
Yes, I can get data in the second application – Billy Liu - MSFT Mar 23 '18 at 09:21
hm.. Could you share somehow your project? I would really appreciate it. – Grzegorz G. Mar 23 '18 at 09:44
Sorry for the late response. Please try [this](https://github.com/Billycool1020/ShareSqlite) – Billy Liu - MSFT Mar 26 '18 at 02:02
You are a man Billy! Thank you very very much, I found the problem and described it in UPDATE section. – Grzegorz G. Mar 26 '18 at 07:08

xamarin.android - how to get access to read and write sqlite db file from shared context?

1 Answers1