Shiva Shiva -4 years ago 252
C# Question

How to extend application class in xamarin android

I want to extend the Android application and I want to override oncreate method.
But for some reason its been very terrible...Only if I remove [Application] I am able to run it but according to this link we have to add [Application]

[Application]
public class MainApp : Application
{
public MainApp(IntPtr javaReference, JniHandleOwnership transfer) : base(javaReference, transfer)
{
}

public override void OnCreate()
{
base.OnCreate();
//app init ...
}
}


Can anybody clarify me what is the rightway to extend application class in xamarin android

Update

If I don't remove [application] I am exactly getting the below error


/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Common.targets:
Error: Error executing task GenerateJavaStubs: Application cannot have
both a type with an [Application] attribute and an
[assembly:Application] attribute. (myapp.Droid)


If I application then it compiles but it throws following runtime error


[AndroidRuntime] Shutting down VM [AndroidRuntime] FATAL EXCEPTION:
main [AndroidRuntime] Process: com.test.myapp, PID: 6524
[AndroidRuntime] java.lang.RuntimeException: Unable to instantiate
application com.test.myapp.MainApp: java.lang.ClassNotFoundException:
Didn't find class "com.test.myapp.MainApp" on path: DexPathList[[zip
file
"/data/app/com.test.myapp-1/base.apk"],nativeLibraryDirectories=[/data/app/com.test.myapp-1/lib/arm,
/data/app/com.test.myapp-1/base.apk!/lib/armeabi-v7a, /system/lib,
/vendor/lib]] [AndroidRuntime] at
android.app.LoadedApk.makeApplication(LoadedApk.java:802)
[AndroidRuntime] at
android.app.ActivityThread.handleBindApplication(ActivityThread.java:5377)
[AndroidRuntime] at
android.app.ActivityThread.-wrap2(ActivityThread.java)
[AndroidRuntime] at
android.app.ActivityThread$H.handleMessage(ActivityThread.java:1545)
[AndroidRuntime] at
android.os.Handler.dispatchMessage(Handler.java:102) [AndroidRuntime]
at android.os.Looper.loop(Looper.java:154) [AndroidRuntime] at
android.app.ActivityThread.main(ActivityThread.java:6119)
[AndroidRuntime] at java.lang.reflect.Method.invoke(Native Method)
[AndroidRuntime] at
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
[AndroidRuntime] at
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
[AndroidRuntime] Caused by: java.lang.ClassNotFoundException: Didn't
find class "com.test.myapp.MainApp" on path: DexPathList[[zip file
"/data/app/com.test.myapp-1/base.apk"],nativeLibraryDirectories=[/data/app/com.test.myapp-1/lib/arm,
/data/app/com.test.myapp-1/base.apk!/lib/armeabi-v7a, /system/lib,
/vendor/lib]] [AndroidRuntime] at
dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
[AndroidRuntime] at
java.lang.ClassLoader.loadClass(ClassLoader.java:380) [AndroidRuntime]
at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
[AndroidRuntime] at
android.app.Instrumentation.newApplication(Instrumentation.java:992)
[AndroidRuntime] at
android.app.LoadedApk.makeApplication(LoadedApk.java:796)
[AndroidRuntime] ... 9 more


Here is my manifest file

Answer Source

In AssemblyInfo.cs

comment out

     #if DEBUG
    [Application(Debuggable=true)]
    #else
    [Application(Debuggable = false)]
    #endif

and move that on top of your application

#if DEBUG
[Application(Debuggable=true)]
#else
[Application(Debuggable = false)]
#endif
public class MainApp : Application
{
public MainApp(IntPtr javaReference, JniHandleOwnership transfer) : base(javaReference, transfer)
{
}

public override void OnCreate()
{
    base.OnCreate();
    //app init ...
}
}

Basically you have defined it two places that's why this problem occurs. Commenting out in AssemblyInfo.cs and adding in the extended class will work out

FYI:

Manifest is ok

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