Xamarin.Android java.lang.ClassNotFoundException

Question

I'm trying to receive files from external apps using Intent and Action.Send. I chose my app at chooser list and then app trying to start but it crashes:

java.lang.ClassNotFoundException: Didn't find class "net.inlu.Incrypta.MainActivity" on path: DexPathList[[zip file "/data/app/net.inlu.Incrypta-1.apk"],nativeLibraryDirectories=[/data/app-lib/net.inlu.Incrypta-1, /vendor/lib, /system/lib]] at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56) at java.lang.ClassLoader.loadClass(ClassLoader.java:497) at java.lang.ClassLoader.loadClass(ClassLoader.java:457) at android.app.Instrumentation.newActivity(Instrumentation.java:1084) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2115) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2248) at android.app.ActivityThread.access$800(ActivityThread.java:138) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1199) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:136) at android.app.ActivityThread.main(ActivityThread.java:5054) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:515) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:788) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:604) at dalvik.system.NativeStart.main(Native Method)

my manifest file:

    <?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" android:versionCode="6" android:versionName="1.0.1" package="net.inlu.Incrypta" android:installLocation="auto">
    <uses-sdk android:minSdkVersion="19" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />
    <application android:allowBackup="true" android:label="@string/app_name" android:logo="@drawable/Logo" android:theme="@style/StartTheme" android:windowSoftInputMode="stateVisible|adjustPan" android:icon="@drawable/Logo">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.SEND" />
                <category android:name="android.intent.category.DEFAULT" />
                <data android:mimeType="*/*" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.intent.action.SEND_MULTIPLE" />
                <category android:name="android.intent.category.DEFAULT" />
                <data android:mimeType="*/*" />
            </intent-filter>
        </activity>
    </application>
</manifest>

I've seen a lot of such issues for Android, but didn't find anuthing exactly for Xamarin.Android. May be anyone knows how to fix it.

MainActivity :

namespace Android.App
{
    [Activity (MainLauncher = true, Icon = "@drawable/Logo", NoHistory = true)]
    public class MainActivity : Activity
    {
        protected override async void OnCreate (Bundle savedInstanceState)
        {
            BootStrapper.RegisterDependencies(new IoCModule());

            Intent intent = Intent;
            string action = intent.Action;
            string type = intent.Type;

            //Xamarin.Insights.Initialize (XamarinInsights.ApiKey, this);
            base.OnCreate (savedInstanceState);
            //SetContentView(Resource.Layout.splash);
            try
            {
                var srv= BootStrapper.Container.Resolve<IServiceManager>();
                var credentials = await srv.ConnectAsync();
                StartActivity(credentials != null ? typeof(BaseActivity) : typeof(LoginActivity));
            }
            catch (Exception)
            {
                StartActivity(typeof(LoginActivity));
            }
        }
    }
}

Please show the code for your .BaseActivity class - the complaint/error is that this class is not found. — ishmaelMakitla
– ishmaelMakitla, Commented Jun 21, 2016 at 14:25
Do you have attached the [Activity]-attribute to your "BaseActivity"? — Stefan Wanitzek
– Stefan Wanitzek, Commented Jun 21, 2016 at 14:44
@StefanWanitzek, yes, of course, currently MainActivity = BaseActivity, sorry for confusing. — Dmitriy Kaluzhin
– Dmitriy Kaluzhin, Commented Jun 21, 2016 at 14:48
I don't understand the call to StartActivity in the OnCreate-method of the activity completely. However, I ran into some problems with namespace-names that have uppercase letters in the past. Can you try to change your namespace from net.inlu.Incrypta.BaseActivity to net.inlu.incrypta.BaseActivity? (notice the lowercase I in "Incrypta"). — Stefan Wanitzek
– Stefan Wanitzek, Commented Jun 21, 2016 at 14:51

Jon Douglas · Accepted Answer · 2016-06-21 16:34:42Z

3

Try to explicitly change the ACW(Android Callable Wrapper) name of your MainActivity. This can be done multiple ways, but the easiest way would be to use the Name property inside the [Activity] attribute to specify a name. You would then set that name to the name it's looking for.

i.e.

[Activity(Name="net.inlu.incrypta.MainActivity")]

Note: Ensure your namespace follows Java conventions in the sense of a fully qualified name.

EX: com.my.package.ClassName

https://developer.xamarin.com/releases/android/xamarin.android_5/xamarin.android_5.1/#Android_Callable_Wrapper_Naming

answered Jun 21, 2016 at 16:34

Jon Douglas

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2 Comments

Alessandro Caliaro Over a year ago

@JonDouglas I have the same problem. I am using a SplashActivity that calls StartActivity(typeof(MainActivity)); and I have this ClassNotFoundException MainActivity... what can be?

Sreejith Sree Over a year ago

It works for me, for testing purpose, I added the url as a message and tap the url from the message. My problem is app open on the message tab, no new tab is open for the app.

Harrison Wu · Accepted Answer · 2021-08-05 02:50:12Z

0

My case: I referenced Symbol.Xamarin.EMDK. (this is a third-party library) in the Android project. I removed it and the exception disappeared, so your problem may be caused by a third-party library. Or your third-party library does not have the correct permission configuration.

Below is the configuration of my third-party library, it can also solve this issue:

<uses-permission android:name="com.symbol.emdk.permission.EMDK" />
<application android:label="@string/app_name" android:icon="@mipmap/icon">
        <uses-library android:name="com.symbol.emdk" android:required="false" />
</application>

answered Aug 5, 2021 at 2:50

Harrison Wu

4924 silver badges7 bronze badges

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