Xamarin表单，在Visual Studio Android Emulator上运行的应用程序但在真实设备上崩溃

Question

我已经创建了一个应用程序，当构建应用程序在Visual Studio模拟器上运行完美。所以我创建了发布版本并尝试在我的物理android设备上运行应用程序。我在设备上收到以下错误消息。我用过Xam.plugin.media

android.runtime.JavaProxyThrowable：System.NullReferenceException：对象引用未设置为Xamarin.Forms.Platform.Android.FormsAppCompatActivity.InternalSetPage（Xamarin.Forms.Page页面）[0x0006f]中的对象实例：Xamarin.Forms中的0 .Platform.Android.FormsAppCompatActivity.SetMainPage（）[0x0000c] in：0 at Xamarin.Forms.Platform.Android.FormsAppCompatActivity.LoadApplication（Xamarin.Forms.Application application）[0x0025c] in：0 at InterestMatch.Droid.MainActivity.OnCreate （Android.OS.Bundle包）[0x00033]在<9e2a066af7c24de6828dc3a0f4e22d31>：0，在Android.Support.V4.App.FragmentActivity.n_OnCreate_Landroid_os_Bundle_（System.IntPtr jnienv，System.IntPtr native__this，System.IntPtr native_savedInstanceState）[0x0000f] in < 1e89c43d3c7d48b5ba69bfc0b1bdf114>：0 at（wrapper dynamic-method）System.Object：6b534aff-3541-46f2-a92e-ac0022b9c4a7（intptr，intptr，intptr）at md5ed93386354f0e17f050b2885712023ca.MainActivity.n_onCreate（Native Method）at md5ed93386354f0e17f050b2885在Android.app.ActivityThread.performLaunchActivity的android.app.Instrumentation.callActivityOnCreate（Instrumentation.java:1108）的android.app.Activity.performCreate（Activity.java:6303）712023ca.MainActivity.onCreate（MainActivity.java:29）（ActivityThread.java:2402）在android.app.A活动时，Android.app.A活动（活动传递。 .java：1373）在android.app.A.运行时，android.O.Ra上的android.O.Roper.loop（Looper.java:154）的android.os.Handler.dispatchMessage（Handler.java:102）。（ActivityThread.java：5523） at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:739）的com.android.internal.os.ZygoteInit.main（ZygoteInit。）中的java.lang.reflect.Method.invoke（Native Method）。 Java的：629）

这是我的代码

MainActivity.cs

public class MainActivity global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity
{
    protected override void OnCreate(Bundle bundle)
    {
        TabLayoutResource = Resource.Layout.Tabbar;
        ToolbarResource = Resource.Layout.Toolbar;



        Plugin.CurrentActivity.CrossCurrentActivity.Current.Activity = this;

        base.OnCreate(bundle);

        global::Xamarin.Forms.Forms.Init(this, bundle);
        LoadApplication(new App());
    }



    public override void OnRequestPermissionsResult(int requestCode, string[] permissions, Android.Content.PM.Permission[] grantResults)
    {
        PermissionsImplementation.Current.OnRequestPermissionsResult(requestCode, permissions, grantResults);
    }

}

app.xaml.cs

     using InterestMatch.Inter;
     using InterestMatch.Models;
     using System;
     using System.Collections.Generic;
     using System.Linq;
     using System.Text;
     using Xamarin.Auth;
     using Xamarin.Forms;

     namespace InterestM
     {
     public partial class App : Application
{

    public static string AppName { get { return "StoreAccountInfoApp"; } }

    public static ICredentialsService CredentialsService { get; private set; }

    public App ()
    {                      
         var account = AccountStore.Create().FindAccountsForService(App.AppName).FirstOrDefault();

         CredentialsService = new CredentialsService();

        if (CredentialsService.DoCredentialsExist())
        {
            InitializeComponent();               
            MainPage = new NavigationPage(new InterestM.MainMenu(account.Username.ToString()));
        }
        else
        {
            InitializeComponent();
            MainPage = new NavigationPage(new InterestM.Accounts.Login());
        }

    }

    protected override void OnStart ()
    {
        // Handle when your app starts
    }

    protected override void OnSleep ()
    {
        // Handle when your app sleeps
    }

    protected override void OnResume ()
    {
        // Handle when your app resumes
    }
}

}