Xamarin.Forms“App已停止工作”在android上

Question

So I encounterd this error just now and this causes my android application not to work on the device. Whenever I debug my application for android it crashes for some reasont. . As a new user to Xamarin I'm clueless.

Here is the error I`m getting:

[art] Late-enabling -Xcheck:jni
[ContextImpl] Unable to create files subdir /data/data/com.comhuis.saleskicker.sales_kicker/cache
[ContextImpl] Unable to create files subdir /data/data/com.comhuis.saleskicker.sales_kicker/files
[AndroidRuntime] Shutting down VM
[AndroidRuntime] FATAL EXCEPTION: main
[AndroidRuntime] Process: com.comhuis.saleskicker.sales_kicker, PID: 5035
[AndroidRuntime] java.lang.RuntimeException: Unable to get provider mono.MonoRuntimeProvider: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.io.File.getAbsolutePath()' on a null object reference
[AndroidRuntime]    at android.app.ActivityThread.installProvider(ActivityThread.java:5015)
[AndroidRuntime]    at android.app.ActivityThread.installContentProviders(ActivityThread.java:4607)
[AndroidRuntime]    at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4547)
[AndroidRuntime]    at android.app.ActivityThread.access$1500(ActivityThread.java:148)
[AndroidRuntime]    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
[AndroidRuntime]    at android.os.Handler.dispatchMessage(Handler.java:102)
[AndroidRuntime]    at android.os.Looper.loop(Looper.java:135)
[AndroidRuntime]    at android.app.ActivityThread.main(ActivityThread.java:5272)
[AndroidRuntime]    at java.lang.reflect.Method.invoke(Native Method)
[AndroidRuntime]    at java.lang.reflect.Method.invoke(Method.java:372)
[AndroidRuntime]    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:909)
[AndroidRuntime]    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:704)
[AndroidRuntime] Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.io.File.getAbsolutePath()' on a null object reference
[AndroidRuntime]    at mono.MonoPackageManager.LoadApplication(MonoPackageManager.java:27)
[AndroidRuntime]    at mono.MonoRuntimeProvider.attachInfo(MonoRuntimeProvider.java:42)
[AndroidRuntime]    at android.app.ActivityThread.installProvider(ActivityThread.java:5012)
[AndroidRuntime]    ... 11 more
[Process] Sending signal. PID: 5035 SIG: 9

I haven't really got something special in my project. I can't upload a screenshot of my solution just yet but I`ll try and describe it:

My solution exists out of SalesKicker and SalesKicker.Droid . SalesKicker has 3 files MainPage.Xaml MainPage.Xaml.cs SalesKicker.cs . and SalesKicker.Droid contains the usual stuff plus 1 image called delogo.png which I`m using as appicon. This is my MainActivity.cs code:

namespace SalesKicker.Droid
{
    [Activity (Label = @"Sales Kicker", Icon = "@drawable/delogo", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)]
    public class MainActivity :     global::Xamarin.Forms.Platform.Android.FormsApplicationActivity
    {
    protected override void OnCreate (Bundle bundle)
    {
        Xamarin.Insights.Initialize (global::SalesKicker.Droid.XamarinInsights.ApiKey, this);
        base.OnCreate (bundle);
        global::Xamarin.Forms.Forms.Init (this, bundle);
        LoadApplication (new App ());
    }
}

I've also been trying to set some breakpoints. I've tried it on every line and still got the same error over and over again. I also tried to set my "Target Version" to Lollipop 5.0, which is the current software version on my LG G3, and it didn't really have any effect. And I also have every single Android SDK installed. Since I'm quite new to Xamarin I'm clueless. Can someone please tell me what I'm doing wrong here?

Answer 1

I got it after looking at another thread: Why does my Xamarin Android application suddenly require external storage permissions?

I just had to go to: AndroidManifest.xml and set 'Install location' to internalOnly . This worked for me.

Answer 2

Create this folder on your android device if you can.

/data/data/{your.apps.package.name}

Otherwise, uninstall your app then re-install it again.

You may noticed that the exception is rise by "File.getAbsolutePath()".

After decompile my app's .apk package, i found this is cause by getFilesDir() returning null .

// MonoPackageManager.java
String str1 = context.getFilesDir().getAbsolutePath();  // <- Exception
String str2 = context.getCacheDir().getAbsolutePath();