(libGDX android in eclipse) unable to instantiate activity ComponentInfo

Question

I just started Android Game Development and I ran into a stupid problem. I want to run an application on my phone or virtual machine and I'm getting this error:

01-11 21:16:45.362: E/AndroidRuntime(19063): FATAL EXCEPTION: main
01-11 21:16:45.362: E/AndroidRuntime(19063): Process: com.mygdx.game, PID: 19063
01-11 21:16:45.362: E/AndroidRuntime(19063): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.mygdx.game/com.mygdx.game.AndroidLauncher}: java.lang.ClassNotFoundException: Didn't find class "com.mygdx.game.AndroidLauncher" on path: DexPathList[[zip file "/data/app/com.mygdx.game-1/base.apk"],nativeLibraryDirectories=[/data/app/com.mygdx.game-1/lib/arm, /vendor/lib, /system/lib]]
01-11 21:16:45.362: E/AndroidRuntime(19063):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2515)
01-11 21:16:45.362: E/AndroidRuntime(19063):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2723)
01-11 21:16:45.362: E/AndroidRuntime(19063):    at android.app.ActivityThread.access$900(ActivityThread.java:172)
01-11 21:16:45.362: E/AndroidRuntime(19063):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1422)
01-11 21:16:45.362: E/AndroidRuntime(19063):    at android.os.Handler.dispatchMessage(Handler.java:102)
01-11 21:16:45.362: E/AndroidRuntime(19063):    at android.os.Looper.loop(Looper.java:145)
01-11 21:16:45.362: E/AndroidRuntime(19063):    at android.app.ActivityThread.main(ActivityThread.java:5832)
01-11 21:16:45.362: E/AndroidRuntime(19063):    at java.lang.reflect.Method.invoke(Native Method)
01-11 21:16:45.362: E/AndroidRuntime(19063):    at java.lang.reflect.Method.invoke(Method.java:372)
01-11 21:16:45.362: E/AndroidRuntime(19063):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
01-11 21:16:45.362: E/AndroidRuntime(19063):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
01-11 21:16:45.362: E/AndroidRuntime(19063): Caused by: java.lang.ClassNotFoundException: Didn't find class "com.mygdx.game.AndroidLauncher" on path: DexPathList[[zip file "/data/app/com.mygdx.game-1/base.apk"],nativeLibraryDirectories=[/data/app/com.mygdx.game-1/lib/arm, /vendor/lib, /system/lib]]
01-11 21:16:45.362: E/AndroidRuntime(19063):    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
01-11 21:16:45.362: E/AndroidRuntime(19063):    at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
01-11 21:16:45.362: E/AndroidRuntime(19063):    at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
01-11 21:16:45.362: E/AndroidRuntime(19063):    at android.app.Instrumentation.newActivity(Instrumentation.java:1079)
01-11 21:16:45.362: E/AndroidRuntime(19063):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2505)
01-11 21:16:45.362: E/AndroidRuntime(19063):    ... 10 more
01-11 21:16:45.362: E/AndroidRuntime(19063):    Suppressed: java.lang.NoClassDefFoundError: com.mygdx.game.AndroidLauncher
01-11 21:16:45.362: E/AndroidRuntime(19063):        at dalvik.system.DexFile.defineClassNative(Native Method)
01-11 21:16:45.362: E/AndroidRuntime(19063):        at dalvik.system.DexFile.defineClass(DexFile.java:226)
01-11 21:16:45.362: E/AndroidRuntime(19063):        at dalvik.system.DexFile.loadClassBinaryName(DexFile.java:219)
01-11 21:16:45.362: E/AndroidRuntime(19063):        at dalvik.system.DexPathList.findClass(DexPathList.java:321)
01-11 21:16:45.362: E/AndroidRuntime(19063):        at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:54)
01-11 21:16:45.362: E/AndroidRuntime(19063):        ... 14 more
01-11 21:16:45.362: E/AndroidRuntime(19063):    Suppressed: java.lang.ClassNotFoundException: com.mygdx.game.AndroidLauncher
01-11 21:16:45.362: E/AndroidRuntime(19063):        at java.lang.Class.classForName(Native Method)
01-11 21:16:45.362: E/AndroidRuntime(19063):        at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
01-11 21:16:45.362: E/AndroidRuntime(19063):        at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
01-11 21:16:45.362: E/AndroidRuntime(19063):        at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
01-11 21:16:45.362: E/AndroidRuntime(19063):        ... 13 more
01-11 21:16:45.362: E/AndroidRuntime(19063):    Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack available

If you have experienced it, please help me. Have a nice day.

Answer 1

I had this issue running a LibGDX app with Android Studio. The problem was that I had edited the AndroidLauncher.java file instead of my actual main activity file (which has the same name as your game). To fix the issue, make sure you have this in your AndroidLauncher.java file:

package com.mygdx.game;

import android.os.Bundle;

import com.badlogic.gdx.backends.android.AndroidApplication;
import com.badlogic.gdx.backends.android.AndroidApplicationConfiguration;
import com.mygdx.game.myGame;

public class AndroidLauncher extends AndroidApplication {
     @Override
     protected void onCreate (Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         AndroidApplicationConfiguration config = new AndroidApplicationConfiguration();
         initialize(new myGame(), config);
    }
}

(You should change "myGame" to your own app's name).

Answer 2

Right click on the android project and click properties -> Java Build Path -> Order and Export, and tick all the boxes.

Clean the project and rebuild.

The error comes when switching from different android API's in eclipse.

Also usually this happens on a new libGDX project when you don't have the default Android SDK (mine was 19 which I don't have), which is fixed by Project -> properties -> Android, and select the build target.

Always clean the project after making these changes.

The above two issues are ones I am always coming across with libGDX and Eclipse, either when importing a project, just setting a new one up or when I'm reinstalling Android SDK's.

Hope this helps. ;-)