First of all, thanks for the effort and I'm looking forward to your app! I just cloned the master branch and compiled in android studio, however, it does not work for me as I get an FC after account selection on my Nexus 5X. I know, it's far from productive state, but I thought I'd let you know anyway.
I have Android 6.0.1 (SDK 23) on my phone (rather old cyanogenmod installation...) and NC14 with Deck 0.50 (newest release) running and the nextcloud files app from f-droid installed (v 3.3.2).
This is the logcat output:
11-21 21:24:19.906 31831-31831/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.nextcloud.client, PID: 31831
Theme: themes:{default=overlay:it.lucci.cm.greyscaletheme, iconPack:system, com.android.systemui=overlay:it.lucci.cm.greyscaletheme, com.android.systemui.navbar=overlay:it.lucci.cm.greyscaletheme}
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.nextcloud.client/com.owncloud.android.ui.activity.SsoGrantPermissionActivity}: java.lang.NullPointerException: Attempt to read from field 'java.lang.String android.accounts.Account.name' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2450)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2510)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1363)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5461)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.NullPointerException: Attempt to read from field 'java.lang.String android.accounts.Account.name' on a null object reference
at com.owncloud.android.ui.activity.SsoGrantPermissionActivity.onCreate(SsoGrantPermissionActivity.java:106)
at android.app.Activity.performCreate(Activity.java:6251)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1108)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2403)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2510)Β
at android.app.ActivityThread.-wrap11(ActivityThread.java)Β
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1363)Β
at android.os.Handler.dispatchMessage(Handler.java:102)Β
at android.os.Looper.loop(Looper.java:148)Β
at android.app.ActivityThread.main(ActivityThread.java:5461)Β
at java.lang.reflect.Method.invoke(Native Method)Β
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)Β
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)Β
Privacy guard is turned off for both files app and deck, also firewall is currently deactivated for testing.
Actually, the files app seems to be crashing with a NPE.