实体框架核心无法在Android三星设备上创建数据库文件

Question

we have an app written with xamarin for android who uses Entity Framework Core. It works on our test devices from Wiko (Android 6.0), HTC (Android 7.1) and Sony(6.0). But on Samsung devices (6.0) we get the following exception on startup:

Microsoft.Data.Sqlite.SqliteException (0x80004005): SQLite Error 1294: 'unable to open database file'.

Complete exception:

    java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
Caused by: java.lang.reflect.InvocationTargetException
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
    ... 1 more
Caused by: android.runtime.JavaProxyThrowable: Microsoft.Data.Sqlite.SqliteException (0x80004005): SQLite Error 1294: 'unable to open database file'.
  at Microsoft.EntityFrameworkCore.Migrations.HistoryRepository.Exists () [0x00000] in <f97b8874924247a39fca91e98b024cf6>:0 
  at Microsoft.EntityFrameworkCore.Migrations.Internal.Migrator.Migrate (System.String targetMigration) [0x00030] in <f97b8874924247a39fca91e98b024cf6>:0 
  at Microsoft.EntityFrameworkCore.RelationalDatabaseFacadeExtensions.Migrate (Microsoft.EntityFrameworkCore.Infrastructure.DatabaseFacade databaseFacade) [0x00010] in <f97b8874924247a39fca91e98b024cf6>:0 
  at FriendsAppDate.Business.AppStart.Start (System.Object hint) [0x0001b] in <c1a86397b9cc451297593cc8cc1289f7>:0 
  at MvvmCross.Droid.Views.MvxSplashScreenActivity.TriggerFirstNavigate () [0x00005] in <f6aebf863dc84be7b380cfec8d459508>:0 
  at MvvmCross.Droid.Views.MvxSplashScreenActivity.InitializationComplete () [0x00009] in <f6aebf863dc84be7b380cfec8d459508>:0 
  at MvvmCross.Droid.Platform.MvxAndroidSetupSingleton.InitializeFromSplashScreen (MvvmCross.Droid.Views.IMvxAndroidSplashScreenActivity splashScreen) [0x00029] in <f6aebf863dc84be7b380cfec8d459508>:0 
  at MvvmCross.Droid.Views.MvxSplashScreenActivity.OnResume () [0x00018] in <f6aebf863dc84be7b380cfec8d459508>:0 
  at Android.App.Activity.n_OnResume (System.IntPtr jnienv, System.IntPtr native__this) [0x00009] in <fca2c02347db4086aed81b5475a315fd>:0 
  at (wrapper dynamic-method) System.Object:b336e942-d75d-4699-a108-3115233929aa (intptr,intptr)
    at mvvmcross.droid.views.MvxSplashScreenActivity.n_onResume(Native Method)
    at mvvmcross.droid.views.MvxSplashScreenActivity.onResume(MvxSplashScreenActivity.java:39)
    at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1286)
    at android.app.Activity.performResume(Activity.java:6987)
    at android.app.ActivityThread.performResumeActivity(ActivityThread.java:4144)
    at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:4245)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1838)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:158)
    at android.app.ActivityThread.main(ActivityThread.java:7224)
    ... 3 more

I get the databse path via:

Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Personal), Constants.DB_NAME);

and this is the same on all devices.

/data/user/0/[AppID]/files/[DbName]

We use the current version of Entity Framework Core 1.1.1 What could be wrong here?

Answer 1

This is an issue with the implementation of SQLite on Samsung devices and should be fixed with 2.0. The EF team had a work around in the issue. See here: https://github.com/aspnet/EntityFramework/issues/7870

Also, what worked for us, was to create the db over raw SQL statements. SQlite DB Browser generates them so you can just copy and paste them.