NoSuchMethodException: <init> [class android.view.View] after generating signed apk

Question

I don't know why NoSuchMethodException is happening in the app. I am using firebase auth + database. I am populating data to recyclerview with FirebaseRecyclerAdapter .I am trying to solve this exception by following this answer but cannot make it possible yet.

public class PostViewHolder extends RecyclerView.ViewHolder {...}

If I use debug version of the app it works perfectly without crashing. But after creating Signed apk app crashed every time. I am using firebase crash reporting in which I am getting this Logcat :

Exception java.lang.RuntimeException: java.lang.NoSuchMethodException: <init> [class android.view.View]
com.b.a.a.b.a ()
android.support.v7.widget.RecyclerView$a.b ()
android.support.v7.widget.RecyclerView$o.a ()
android.support.v7.widget.RecyclerView$o.a ()
android.support.v7.widget.RecyclerView$o.c ()
android.support.v7.widget.LinearLayoutManager$c.a ()
android.support.v7.widget.LinearLayoutManager.a ()
android.support.v7.widget.LinearLayoutManager.a ()
android.support.v7.widget.LinearLayoutManager.c ()
android.support.v7.widget.RecyclerView.M ()
android.support.v7.widget.RecyclerView.p ()
android.support.v7.widget.RecyclerView.c ()
android.support.v7.widget.RecyclerView$1.run ()
android.view.Choreographer$CallbackRecord.run (Choreographer.java:767)
android.view.Choreographer.doCallbacks (Choreographer.java:580)
android.view.Choreographer.doFrame (Choreographer.java:549)
android.view.Choreographer$FrameDisplayEventReceiver.run (Choreographer.java:753)
android.os.Handler.handleCallback (Handler.java:739)
android.os.Handler.dispatchMessage (Handler.java:95)
android.os.Looper.loop (Looper.java:135)
android.app.ActivityThread.main (ActivityThread.java:5233)
java.lang.reflect.Method.invoke (Method.java)
java.lang.reflect.Method.invoke (Method.java:372)
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run (ZygoteInit.java:898)
com.android.internal.os.ZygoteInit.main (ZygoteInit.java:693)

Caused by java.lang.NoSuchMethodException: <init> [class android.view.View]
java.lang.Class.getConstructor (Class.java:531)
java.lang.Class.getConstructor (Class.java:495)
com.b.a.a.b.a ()
android.support.v7.widget.RecyclerView$a.b ()
android.support.v7.widget.RecyclerView$o.a ()
android.support.v7.widget.RecyclerView$o.a ()
android.support.v7.widget.RecyclerView$o.c ()
android.support.v7.widget.LinearLayoutManager$c.a ()
android.support.v7.widget.LinearLayoutManager.a ()
android.support.v7.widget.LinearLayoutManager.a ()
android.support.v7.widget.LinearLayoutManager.c ()
android.support.v7.widget.RecyclerView.M ()
android.support.v7.widget.RecyclerView.p ()
android.support.v7.widget.RecyclerView.c ()
android.support.v7.widget.RecyclerView$1.run ()
android.view.Choreographer$CallbackRecord.run (Choreographer.java:767)
android.view.Choreographer.doCallbacks (Choreographer.java:580)
android.view.Choreographer.doFrame (Choreographer.java:549)
android.view.Choreographer$FrameDisplayEventReceiver.run (Choreographer.java:753)
android.os.Handler.handleCallback (Handler.java:739)
android.os.Handler.dispatchMessage (Handler.java:95)
android.os.Looper.loop (Looper.java:135)
android.app.ActivityThread.main (ActivityThread.java:5233)
java.lang.reflect.Method.invoke (Method.java)
java.lang.reflect.Method.invoke (Method.java:372)
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run (ZygoteInit.java:898)
com.android.internal.os.ZygoteInit.main (ZygoteInit.java:693)

What is wrong with my code every thing worked fine in debug version but signed app crashed when open.

Answer 1

This is because ProGuard is obfuscating your apk to make it harder for hackers to reverse-engineering your apk. If you think obfuscation is not needed, change this in your gradle configuration:

minifyEnabled false

Alternatively, you can let ProGuard skip obfuscation of the support libraries by using this:

minifyEnabled true
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'

Add a file proguard-rules.txt and try adding these lines:

-keep class android.support.v7.internal.** { *; }
-keep interface android.support.v7.internal.** { *; }
-keep class android.support.v7.** { *; }
-keep interface android.support.v7.** { *; }