Android.views.windowmanagerbadtokenexception: unable to add window -- token android.os.binderproxy

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C#

Android

Xamarin

I am developing an android application using xamarin.

I am creating custom toast messages similar to android Toast.MakeText().please see my c#.net below code

var @params = new WindowManagerLayoutParams(
ViewGroup.LayoutParams.WrapContent,
ViewGroup.LayoutParams.WrapContent,
WindowManagerTypes.Toast,
WindowManagerFlags.NotFocusable | WindowManagerFlags.NotTouchable,
Android.Graphics.Format.Translucent);

Android.Content.Res.Configuration config = activity.Resources.Configuration;

@params.Gravity = Gravity.GetAbsoluteGravity((GravityFlags.CenterHorizontal | GravityFlags.Bottom), (GravityFlags)config.LayoutDirection);
@params.X = 0;
@params.Y = (int)TypedValue.ApplyDimension(ComplexUnitType.Dip, 64f, activity.Resources.DisplayMetrics);
@params.WindowAnimations = Android.Resource.Style.AnimationToast;
@params.PackageName = activity.PackageName;
@params.Token = activity.Window.Attributes.Token;

if ((@params.Gravity & GravityFlags.HorizontalGravityMask) == GravityFlags.FillHorizontal)
{
@params.HorizontalWeight = 1.0f;
}

if ((@params.Gravity & GravityFlags.VerticalGravityMask) == GravityFlags.FillVertical)
{
@params.VerticalWeight = 1.0f;
}

try
{
activity.WindowManager.AddView(msg.MView, @params);
}
catch(System.Exception ex)
{
}

While adding the view to Windowmanager I am getting the following exception

{Android.Views.WindowManagerBadTokenException: Unable to add window -- token android.os.BinderProxy@901e8d6 is not valid; is your activity running?
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in :0
at Java.Interop.JniEnvironment+InstanceMethods.CallVoidMethod (Java.Interop.JniObjectReference instance, Java.Interop.JniMethodInfo method, Java.Interop.JniArgumentValue* args) [0x00069] in <3cb12bce834a498199b2be6cd3e00922>:0
at Android.Runtime.JNIEnv.CallVoidMethod (System.IntPtr jobject, System.IntPtr jmethod, Android.Runtime.JValue* parms) [0x0000e] in :0
at Android.Views.IWindowManagerInvoker.AddView (Android.Views.View view, Android.Views.ViewGroup+LayoutParams params) [0x0007c] in :0
at GSP.Phone.Controls.ToastCompat+<>c__DisplayClass11_0.b__0 () [0x00162] in ToastCompat.cs:152
--- End of managed Android.Views.WindowManagerBadTokenException stack trace ---
android.view.WindowManager$BadTokenException: Unable to add window -- token android.os.BinderProxy@901e8d6 is not valid; is your activity running?
at android.view.ViewRootImpl.setView(ViewRootImpl.java:920)
at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:377)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:105)
at mono.java.lang.RunnableImplementor.n_run(Native Method)
at mono.java.lang.RunnableImplementor.run(RunnableImplementor.java:30)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6823)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1557)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1445)
}

seems to me while assigning the token to window manager params is the problem. am I assigning the right token value(activity.Window.Attributes.Token) to window manager params?

Please help me how to resolve the Android.Views.WindowManagerBadTokenException

Thank you,
K.Nagendra Babu

What I have tried:

I tried to create custom toast messages similar android Toast messages but while adding the view to WindowManager it throwing Android.Views.WindowManagerBadTokenException