Xamarin.Forms Google API使用身份提供者对用户进行身份验证

我仍然习惯于Xamarin.Forms，并且我处于非常基础的水平.我针对该问题浏览了许多文章，但最终无法解决.所以...

I am still getting used to Xamarin.Forms and I am on very basic level. I went through many articles for my issue, but to the end couldn't resolve it. So...

当前，我正在尝试在使用Droid和iOS(无WP)的Xamarin.Forms应用程序中添加Google身份验证. 到目前为止，我正在此处进行操作.我正在使用Xamarin.Auth对Google进行身份验证.

Currently I am trying to add Google authentication inside my Xamarin.Forms application, which use Droid and iOS (no WP). So far I am following guide from here. I am using Xamarin.Auth to authenticate to Google.

这是我源代码中的一部分.

Here is some part from my source code.

    private async void GoogleSheetsButton_Tapped()
    {
        string clientId = null;
        string redirectUri = null;

        if (Device.RuntimePlatform == Device.iOS)
        {
            clientId = Constants.iOSClientId;
            redirectUri = Constants.iOSRedirectUrl;
        }
        else if (Device.RuntimePlatform == Device.Android)
        {
            clientId = Constants.AndroidClientId;
            redirectUri = Constants.AndroidRedirectUrl;
        }

        var authenticator = new OAuth2Authenticator(
            clientId,
            null,
            Constants.Scope,
            new Uri(Constants.AuthorizeUrl),
            new Uri(redirectUri),
            new Uri(Constants.AccessTokenUrl),
            null,
            true);

        authenticator.Completed += OnAuthCompleted;
        authenticator.Error += OnAuthError;

        AuthenticationState.Authenticator = authenticator;

        var presenter = new Xamarin.Auth.Presenters.OAuthLoginPresenter();
        presenter.Login(authenticator);
    }

问题出在我的方法完成工作之后.所以在我的最后一行之后:

The problem is coming after my method complete it's work. So after my last line:

    presenter.Login(authenticator);

一切看起来都很好，并且正在调试我正在跟踪编译器退出方法而没有任何错误，但是随后我收到异常，您可以看到 没有兼容的代码正在运行 ".

everything looks alright and debugging I am following that compiler goes out of method without any errors, but then I receive exception, which you can see here. It's "No compatible code running".

以下是有关我的源代码的更多信息:

Here some more information regarding my source code:

• 用于客户端ID和URL的常量"类的来源

    public static class Constants
    {
        public static string AppName = "....";

        // OAuth
        // For Google login, configure at https://console.developers.google.com/
        public static string iOSClientId = "6.....apps.googleusercontent.com";
        public static string AndroidClientId = "6.....apps.googleusercontent.com";

        // These values do not need changing
        public static string Scope = "https://www.googleapis.com/auth/userinfo.email";
        public static string AuthorizeUrl = "https://accounts.google.com/o/oauth2/auth";
        public static string AccessTokenUrl = "https://www.googleapis.com/oauth2/v4/token";
        public static string UserInfoUrl = "https://www.googleapis.com/oauth2/v2/userinfo";

        // Set these to reversed iOS/Android client ids, with :/oauth2redirect appended
        public static string iOSRedirectUrl = "com.googleusercontent.apps.6......h:/oauth2redirect";
        public static string AndroidRedirectUrl = "com.googleusercontent.apps.6......l:/oauth2redirect";
    }

• 关于身份验证完成/错误的已实现方法的来源，实际上由于我的错误我仍然无法击中

 

    async void OnAuthCompleted(object sender, AuthenticatorCompletedEventArgs e)
    {
        var authenticator = sender as OAuth2Authenticator;
        if (authenticator != null)
        {
            authenticator.Completed -= OnAuthCompleted;
            authenticator.Error -= OnAuthError;
        }

        GoogleLoginUser user = null;
        if (e.IsAuthenticated)
        {
            var request = new OAuth2Request("GET", new Uri(Constants.UserInfoUrl), null, e.Account);
            var response = await request.GetResponseAsync();
            if (response != null)
            {
                string userJson = await response.GetResponseTextAsync();
                user = JsonConvert.DeserializeObject(userJson);
            }

            if (_account != null)
            {
                _store.Delete(_account, Constants.AppName);
            }

            await _store.SaveAsync(_account = e.Account, Constants.AppName);
            await DisplayAlert("Email address", user.Email, "OK");
        }
    }

    void OnAuthError(object sender, AuthenticatorErrorEventArgs e)
    {
        var authenticator = sender as OAuth2Authenticator;
        if (authenticator != null)
        {
            authenticator.Completed -= OnAuthCompleted;
            authenticator.Error -= OnAuthError;
        }

        var message = e.Message;
    }

• 我在其中添加的Android MainActivity的来源

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

            base.OnCreate(bundle);

            Forms.Init(this, bundle);
            global::Xamarin.Auth.Presenters.XamarinAndroid.AuthenticationConfiguration.Init(this, bundle);

            MobileBarcodeScanner.Initialize(Application);

            LoadApplication(new App());
        }
    }

• UrlSchemeInterceptorActivity的来源

    [Activity(Label = "CustomUrlSchemeInterceptorActivity", NoHistory = true, LaunchMode = LaunchMode.SingleTop)]
    [IntentFilter(new[] { Intent.ActionView }, Categories = new[] { Intent.CategoryDefault, Intent.CategoryBrowsable }, DataSchemes = new[] { "com.googleusercontent.apps.6......l" }, DataPath = "/oauth2redirect")]
    public class CustomUrlSchemeInterceptorActivity : Activity
    {
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);

            var uri = new Uri(Intent.Data.ToString());

            AuthenticationState.Authenticator.OnPageLoading(uri);

            Finish();
        }
    }

这是我深入研究的主要文章=> 链接1 ，链接2 和链接3 ，但仍然无法解决问题.

Here are the main articles I went through deeply => Link 1, Link 2 and Link 3, but still couldn't resolve the issue.

我不确定错误是从哪里来的，或者我可以继续调试它来解决问题.

I am not sure where the error comes from, or can I can I continue debugging it to resolve issue.

预先感谢

解决方案

1. 在Android项目属性内将android编译器更改为android 7.0. 截屏
2. 确保在Android Manifest中，您的目标是SDK版本. 截屏
3. 将所有"Xamarin.Android.*" nuget软件包更新为最低版本25.4.0.1.目前最有可能达到23.3.0.我发现有关更新它的依赖性的问题，因此我进行了手动上传.我去手动下载了每个软件包，并将其移到packages文件夹.然后，我创建了自己的软件包源，并为我的文件夹软件包提供了路径，并用它来安装已经下载的NuGet软件包. 截屏
4. 之后我的问题解决了.

1. Change android compiler to Android 7.0 inside Android project properties. Screenshot
2. Make sure that inside Android Manifest your target is SDK Version. Screenshot
3. Update all "Xamarin.Android.*" nuget packages to minimum version 25.4.0.1. Most probably they're currently to 23.3.0. I found problems with dependencies on updating it, so I make manual upload. I went and download manually each package and move it to packages folder. Then I created my own package source and give for path my folder packages and I used it to install already downloaded NuGet packages. Screenshot
4. After that my issue was solved.