c#CRC643F46942D9DD1FF9。FormsSeekBar。设置按下的窗体seekbar。java，第63行java。互操作。JavaLocationException:在xamarin中抛出。形式

Question

System.NotSupportedException: Unable to activate instance of type Xamarin.Forms.Platform.Android.FormsSeekBar from native handle 0xffeef5ac (key_handle 0x4db393b). at Java.Interop.TypeManager.CreateInstance (System.IntPtr handle, Android.Runtime.JniHandleOwnership transfer, System.Type targetType) [0x0017e] in <5029faf3775942b79c91624f8b49b012>:0 at Java.Lang.Object.GetObject (System.IntPtr handle, Android.Runtime.JniHandleOwnership transfer, System.Type type) [0x00023] in <5029faf3775942b79c91624f8b49b012>:0 at Java.Lang.Object._GetObject[T] (System.IntPtr handle, Android.Runtime.JniHandleOwnership transfer) [0x00017] in <5029faf3775942b79c91624f8b49b012>:0 at Java.Lang.Object.GetObject[T] (System.IntPtr handle, Android.Runtime.JniHandleOwnership transfer) [0x00000] in <5029faf3775942b79c91624f8b49b012>:0 at Java.Lang.Object.GetObject[T] (System.IntPtr jnienv, System.IntPtr handle, Android.Runtime.JniHandleOwnership transfer) [0x00006] in <5029faf3775942b79c91624f8b49b012>:0 at Android.Views.View.n_SetPressed_Z (System.IntPtr jnienv, System.IntPtr native__this, System.Boolean pressed) [0x00000] in <5029faf3775942b79c91624f8b49b012>:0 at (wrapper dynamic-method) Android.Runtime.DynamicMethodNameCounter.152(intptr,intptr,bool) --- End of inner exception stack trace --- System.MissingMethodException: No constructor found for

Xamarin.Forms.Platform.Android.FormsSeekBar::.ctor(System.IntPtr, Android.Runtime.JniHandleOwnership)
at Java.Interop.TypeManager.CreateProxy (System.Type type, System.IntPtr handle, Android.Runtime.JniHandleOwnership transfer) [0x000b5] in <5029faf3775942b79c91624f8b49b012>:0
at Java.Interop.TypeManager.CreateInstance (System.IntPtr handle, Android.Runtime.JniHandleOwnership transfer, System.Type targetType) [0x00111] in <5029faf3775942b79c91624f8b49b012>:0
--- End of inner exception stack trace ---
Java.Interop.JavaLocationException: Exception of type 'Java.Interop.JavaLocationException' was thrown.
at Java.Lang.Error: Exception of type 'Java.Lang.Error' was thrown.
at java.lang.Error: Java callstack:
at crc643f46942d9dd1fff9.FormsSeekBar.n_setPressed(Native Method)
at crc643f46942d9dd1fff9.FormsSeekBar.setPressed(FormsSeekBar.java:63)
at 安卓.view.ViewGroup.dispatchSetPressed(ViewGroup.java:5348)
at 安卓.view.View.setPressed(View.java:12220)
at 安卓.view.ViewGroup.dispatchSetPressed(ViewGroup.java:5348)
at 安卓.view.View.setPressed(View.java:12220)
at 安卓.view.ViewGroup.dispatchSetPressed(ViewGroup.java:5348)
at 安卓.view.View.setPressed(View.java:12220)
at 安卓.view.ViewGroup.dispatchSetPressed(ViewGroup.java:5348)
at 安卓.view.View.setPressed(View.java:12220)
at 安卓.view.ViewGroup.dispatchSetPressed(ViewGroup.java:5348)
at 安卓.view.View.setPressed(View.java:12220)
at 安卓.view.ViewGroup.dispatchSetPressed(ViewGroup.java:5348)
at 安卓.view.View.setPressed(View.java:12220)
at 安卓.view.ViewGroup.dispatchSetPressed(ViewGroup.java:5348)
at 安卓.view.View.setPressed(View.java:12220)
at 安卓.view.View$UnsetPressedState.run(View.java:29702)
at 安卓.os.Handler.handleCallback(Handler.java:883)
at 安卓.os.Handler.dispatchMessage(Handler.java:100)
at 安卓.os.Looper.loop(Looper.java:237)
at 安卓.app.ActivityThread.main(ActivityThread.java:8019)
at java.lang.reflect.Method.invoke(Native Method)
at com.安卓.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)

应用程序在Xamarin崩溃。Android 9的表单。并在appcenter中重复了此崩溃。需要知道这个问题是什么，为什么会发生。请帮助解决这个问题