java.lang.ClassNotFoundException: Didn't find

Question

I'm currently working on a project in which I have to use purely native ndk. It worked when I try running an helloworld example from Irrlicht engine source. Then I try using it in my project following the same format of that example. But I got:

03-14 01:40:05.308: E/AndroidRuntime(799): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.irrlicht.example1/android.app.POMActivity}: java.lang.ClassNotFoundException: Didn't find class "android.app.POMActivity" on path: DexPathList[[zip file "/data/app/com.irrlicht.example1-2.apk"],nativeLibraryDirectories=[/data/app-lib/com.irrlicht.example1-2, /system/lib]]

while running my project.

Here is my main.cpp file:

#include <android/log.h>
#include <jni.h>
#include <android_native_app_glue.h>
#include "android_tools.h"
#ifdef _IRR_ANDROID_PLATFORM_
void android_main(android_app* app)
{
__android_log_print(4 , "pom" , "nothing");
}

#endif

in Android.mk:

LOCAL_PATH := $(call my-dir)/..
IRRLICHT_PROJECT_PATH := $(LOCAL_PATH)
include $(CLEAR_VARS)
LOCAL_MODULE := Irrlicht
LOCAL_SRC_FILES := /home/karthik/Android/Essentials/ogl-es/lib/Android/libIrrlicht.a
include $(PREBUILT_STATIC_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := HelloWorldMobile1
LOCAL_CFLAGS := -D_IRR_ANDROID_PLATFORM_ -pipe -fno-exceptions -fno-rtti -fstrict-aliasing
LOCAL_C_INCLUDES := -I ../../include -I /home/karthik/Android/Essentials/ogl-es/include -I /home/karthik/Android/json/jsoncpp-src-0.5.0/libs/linux-gcc-4.8 -I /home/karthik/Android/json/jsoncpp-src-0.5.0/include/json 
LOCAL_SRC_FILES :=  android_tools.cpp main.cpp
LOCAL_LDLIBS := -lEGL -llog -lGLESv1_CM -lGLESv2 -lz -landroid -ldl 
LOCAL_STATIC_LIBRARIES := Irrlicht android_native_app_glue
include $(BUILD_SHARED_LIBRARY)
$(call import-module,android/native_app_glue)

And I have given Activity name in AndroidManifest.xml:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.irrlicht.example1"
    android:versionCode="1"
    android:versionName="1.0">
...
<application android:icon="@drawable/irr_icon" android:label="HelloWorldMobile1" android:theme="@android:style/Theme.NoTitleBar.Fullscreen" android:debuggable="true">
        <activity android:name="android.app.POMActivity"
        android:label="HelloWorldMobile1"
        android:launchMode="singleTask"
        android:configChanges="orientation|keyboardHidden"
        android:screenOrientation="portrait"
        android:clearTaskOnLaunch="true">
        <meta-data android:name="android.app.lib_name" android:value="HelloWorldMobile1" />                     

What is the mistake I am doing here? I'll post full code if necassary.

Answer 1

I had a similar problem, here's my solution:

1. Right click on your project and select Properties.
2. Select Java Build Path from the menu on the left.
3. Select the Order and Export tab.
4. From the list make sure the libraries or external jars you added to your project are checked.
5. Finally, clean your project & run.

You may also check this answer.

Answer 2

Ashik abbas answer (disable Instant Run) work for me, but i need Instant Run, finally i found solution which is helpful for me. just disable minifyEnabled. go to build.gradle(Module: app) in debug block and disable minifyEnabled:

debug {
            minifyEnabled false

        }

Answer 3

If the project was compiling before just clear the cache by using :

./gradlew clean

or

./gradlew cleanBuildCache

or for windows

gradlew cleanBuildCache

https://developer.android.com/studio/build/build-cache.html

Answer 4

For me the issue appeared after i created a signed APK. To fix it, i generated a new, debug apk using Run / Build APK. After that, Run(cmd+r) works again without this error.

Answer 5

When you are using multidex , then try to extend your application class with MultiDexAppication instead of Application and override below method this required for Android below 5.0 (because 5.0 and above support to the multidex)

@Override
protected void attachBaseContext(Context base)
{
    super.attachBaseContext(base);
    MultiDex.install(BaseApplication.this);
}

and in dependencies add this

compile 'com.android.support:multidex:1.0.1'

Answer 6

Just Change your folder name from lib to libs ,

Then you will see some error marks in your project, to resolve this rightClick on project >

Properties > Java Build Path > libraries :

Remove all the library with red marks on it, then apply > ok > after that clean your project . TADA see the magic :)