如何在 xamarin android 中扩展应用程序类 [英] How to extend application class in xamarin android

问题描述

我想扩展 Android 应用程序并且我想覆盖 oncreate 方法.但由于某种原因它非常糟糕......只有当我删除 [Application] 我才能运行它但根据这个 link 我们必须添加 [Application]

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 ...
}
}

任何人都可以向我澄清在 xamarin android 中扩展应用程序类的正确方法是什么

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

更新

如果我不删除 [application]，我就会收到以下错误

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:错误:执行任务 GenerateJavaStubs 时出错:应用程序不能有具有 [Application] 属性的类型和[程序集:应用程序] 属性.(myapp.Droid)

/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)

如果我应用程序然后它编译但它抛出以下运行时错误

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

[AndroidRuntime] 关闭虚拟机 [AndroidRuntime] 致命异常:主 [AndroidRuntime] 进程:com.test.myapp，PID:6524[AndroidRuntime] java.lang.RuntimeException:无法实例化应用程序 com.test.myapp.MainApp: java.lang.ClassNotFoundException:在路径上没有找到类com.test.myapp.MainApp":DexPathList[[zip文件"/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] 在android.app.LoadedApk.makeApplication(LoadedApk.java:802)[AndroidRuntime] 在android.app.ActivityThread.handleBindApplication(ActivityThread.java:5377)[AndroidRuntime] 在android.app.ActivityThread.-wrap2(ActivityThread.java)[AndroidRuntime] 在android.app.ActivityThread$H.handleMessage(ActivityThread.java:1545)[AndroidRuntime] 在android.os.Handler.dispatchMessage(Handler.java:102) [AndroidRuntime]在 android.os.Looper.loop(Looper.java:154) [AndroidRuntime] 在android.app.ActivityThread.main(ActivityThread.java:6119)[AndroidRuntime] 在 java.lang.reflect.Method.invoke(Native Method)[AndroidRuntime] 在com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)[AndroidRuntime] 在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)[AndroidRuntime] 引起:java.lang.ClassNotFoundException:没有在路径上找到类com.test.myapp.MainApp":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] 在dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)[AndroidRuntime] 在java.lang.ClassLoader.loadClass(ClassLoader.java:380) [AndroidRuntime]在 java.lang.ClassLoader.loadClass(ClassLoader.java:312)[AndroidRuntime] 在android.app.Instrumentation.newApplication(Instrumentation.java:992)[AndroidRuntime] 在android.app.LoadedApk.makeApplication(LoadedApk.java:796)[AndroidRuntime] ... 9 更多

[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

这是我的清单文件

推荐答案

在 AssemblyInfo.cs

In AssemblyInfo.cs

注释掉

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

并将其移至您的应用程序之上

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 ...
}
}

基本上你已经定义了两个地方，这就是为什么会出现这个问题.在AssemblyInfo.cs 中注释掉并添加扩展类就可以了

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

仅供参考:

清单没问题

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