Unity Android with AppCompat Rejecting re-init on previously-failed class java.lang.Class

Question

Hi I am building a Unity app which uses Android library as one of the plugin. This Android library uses AppCompat.

Reading from the Unity blog, I realized that Unity does not include the appcompat library during the building due to several reasons (mainly the APK size) but it still allow the library to be added manually. (blog here: http://blogs.unity3d.com/2015/07/16/android-themes-in-unity/)

Thus I've added the library inside Assets/Plugins/Android/ which then my Unity app is able to build successfully and generate the APK file.

The problem comes when I tried to open the app which supposedly start an activity that was defined in the android library. This particular activity uses appcompat library. I get the following error message from logcat

I/art     (19482): Rejecting re-init on previously-failed class java.lang.Class<android.support.v7.app.AppCompatActivity>
I/art     (19482): Rejecting re-init on previously-failed class java.lang.Class<android.support.v7.app.AppCompatActivity>
W/ActivityManager(  890):   Force finishing activity amillardo.test.blasterescopic/com.test.player.MainActivity
I/art     (19482): Rejecting re-init on previously-failed class java.lang.Class<android.support.v7.app.ActionBarActivity>
I/art     (19482): Rejecting re-init on previously-failed class java.lang.Class<android.support.v7.app.ActionBarActivity>
I/art     (19482): Rejecting re-init on previously-failed class java.lang.Class<com.test.player.MainActivity>
E/AndroidRuntime(19482): FATAL EXCEPTION: main
E/AndroidRuntime(19482): Process: amillardo.test.blasterescopic, PID: 19482
E/AndroidRuntime(19482): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{amillardo.test.blasterescopic/com.test.player.MainActivity}: java.lang.ClassNotFoundException: Didn't find class "com.test.player.MainActivity" on path: DexPathList[[zip file "/data/app/amillardo.test.blasterescopic-1/base.apk"],nativeLibraryDirectories=[/data/app/amillardo.test.blasterescopic-1/lib/arm, /system/lib, /vendor/lib, system/vendor/lib, system/vendor/lib/egl, system/lib/hw]]
E/AndroidRuntime(19482):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2322)
E/AndroidRuntime(19482):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2474)
E/AndroidRuntime(19482):     at android.app.ActivityThread.access$800(ActivityThread.java:144)
E/AndroidRuntime(19482):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1359)
E/AndroidRuntime(19482):     at android.os.Handler.dispatchMessage(Handler.java:102)
E/AndroidRuntime(19482):     at android.os.Looper.loop(Looper.java:155)
E/AndroidRuntime(19482):     at android.app.ActivityThread.main(ActivityThread.java:5696)
E/AndroidRuntime(19482):     at java.lang.reflect.Method.invoke(Native Method)
E/AndroidRuntime(19482):     at java.lang.reflect.Method.invoke(Method.java:372)
E/AndroidRuntime(19482):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1028)
E/AndroidRuntime(19482):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:823)
E/AndroidRuntime(19482): Caused by: java.lang.ClassNotFoundException: Didn't find class "com.test.player.MainActivity" on path: DexPathList[[zip file "/data/app/amillardo.test.blasterescopic-1/base.apk"],nativeLibraryDirectories=[/data/app/amillardo.test.blasterescopic-1/lib/arm, /system/lib, /vendor/lib, system/vendor/lib, system/vendor/lib/egl, system/lib/hw]]
E/AndroidRuntime(19482):     at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
E/AndroidRuntime(19482):     at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
E/AndroidRuntime(19482):     at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
E/AndroidRuntime(19482):     at android.app.Instrumentation.newActivity(Instrumentation.java:1083)
E/AndroidRuntime(19482):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2312)
E/AndroidRuntime(19482):     ... 10 more
E/AndroidRuntime(19482):     Suppressed: java.lang.NoClassDefFoundError: com.test.player.MainActivity
E/AndroidRuntime(19482):         at dalvik.system.DexFile.defineClassNative(Native Method)
E/AndroidRuntime(19482):         at dalvik.system.DexFile.defineClass(DexFile.java:226)
E/AndroidRuntime(19482):         at dalvik.system.DexFile.loadClassBinaryName(DexFile.java:219)
E/AndroidRuntime(19482):         at dalvik.system.DexPathList.findClass(DexPathList.java:321)
E/AndroidRuntime(19482):         at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:54)
E/AndroidRuntime(19482):         ... 14 more
E/AndroidRuntime(19482):     Suppressed: java.lang.ClassNotFoundException: com.test.player.MainActivity
E/AndroidRuntime(19482):         at java.lang.Class.classForName(Native Method)
E/AndroidRuntime(19482):         at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
E/AndroidRuntime(19482):         at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
E/AndroidRuntime(19482):         at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
E/AndroidRuntime(19482):         ... 13 more
E/AndroidRuntime(19482):     Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack available
I/TrimMemoryManager( 1561): [trimMemory] 20
E/ActivityManager(  890): App crashed! Process: amillardo.test.blasterescopic

So yup I am stuck here. Anyone has any suggestion? Thanks!

Solution

I finally got it working after trying all methods I can think of!

I suspect it is because the appcompat library actually requires or dependent on support-v4 library.

Initially I only imported the appcompat library from android sdk to my unity project. But when I imported the support-v4 library, the errors are no longer there!

So hope this helps anyone who need it.