Witam.
Kilkukrotnie próbowałem zrobić typowe ustawienie jakiejs funkcji dla buttona, jednak za każdym razem w aplikacji po naciśnięciu jest crash.
Naprawdę nie wiem, co jest źle. Mam to:
public void button2test(View v) {
//cokolwiek
}
i ustawiam tego void'a w OnClick.
02/28 23:35:30: Launching app
$ adb push S:\Users\Michal\AndroidStudioProjects\testowy\app\build\outputs\apk\app-debug.apk /data/local/tmp/com.example.michal.testowy
$ adb shell pm install -r "/data/local/tmp/com.example.michal.testowy"
Success
$ adb shell am start -n "com.example.michal.testowy/com.example.michal.testowy.MainActivity" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
Client not ready yet..Waiting for process to come online
Waiting for process to come online
Connected to process 2286 on device emulator-5554
W/System: ClassLoader referenced unknown path: /data/app/com.example.michal.testowy-2/lib/x86
W/art: Before Android 4.1, method android.graphics.PorterDuffColorFilter android.support.graphics.drawable.VectorDrawableCompat.updateTintFilter(android.graphics.PorterDuffColorFilter, android.content.res.ColorStateList, android.graphics.PorterDuff$Mode) would have incorrectly overridden the package-private method in android.graphics.drawable.Drawable
I/OpenGLRenderer: Initialized EGL, version 1.4
D/OpenGLRenderer: Swap behavior 1
E/EGL_emulation: tid 2403: eglSurfaceAttrib(1146): error 0x3009 (EGL_BAD_MATCH)
W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface 0xaf3e3a20, error=EGL_BAD_MATCH
D/AndroidRuntime: Shutting down VM
--------- beginning of crash
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.michal.testowy, PID: 2286
java.lang.IllegalStateException: Could not find method button3test (MainActivity)(View) in a parent or ancestor Context for android:onClick attribute defined on view class android.support.v7.widget.AppCompatButton with id 'button'
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:327)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:284)
at android.view.View.performClick(View.java:5610)
at android.view.View$PerformClick.run(View.java:22265)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
JetBrains Android Studio 
Java 
