Xamarin Android：通过标准 api（电子邮件、Facebook 等）共享图像

Question

我需要在 Xamarin 中实现标准共享 Android。我找到并更改了 Xamarin 的代码。看起来像这样

    public void Share (string title, string content)
    {
        if (string.IsNullOrEmpty (title) || string.IsNullOrEmpty (content))
            return;

        var name = Application.Context.Resources.GetResourceName (Resource.Drawable.icon_120).Replace (':', '/');
        var imageUri = Uri.Parse ("android.resource://" + name);
        var sharingIntent = new Intent ();
        sharingIntent.SetAction (Intent.ActionSend);
        sharingIntent.SetType ("image/*");
        sharingIntent.PutExtra (Intent.ExtraText, content);
        sharingIntent.PutExtra (Intent.ExtraStream, imageUri);
        sharingIntent.AddFlags (ActivityFlags.GrantReadUriPermission);
        ActivityContext.Current.StartActivity (Intent.CreateChooser (sharingIntent, title));
    }

此代码调用标准共享功能，但当我选择 Facebook 或电子邮件时，我得到 "Cant load image"。文件位于“/Resources/drawable-xhdpi/icon_120.png”。

你能指出我做错了什么吗？

Answer 1

我认为该应用程序图标是在您的应用程序私有的目录中创建的，因此其他应用程序无法访问它。

您需要将它保存在其他应用程序可以访问的地方，然后从该位置共享它，如下所示：

public void Share (string title, string content)
{
    if (string.IsNullOrEmpty (title) || string.IsNullOrEmpty (content))
                return;

    Bitmap b = BitmapFactory.DecodeResource(Resources,Resource.Drawable.icon_120);

    var tempFilename = "test.png";
    var sdCardPath = Android.OS.Environment.ExternalStorageDirectory.AbsolutePath;
    var filePath = System.IO.Path.Combine(sdCardPath, tempFilename);
    using (var os = new FileStream(filePath, FileMode.Create))
    {
        b.Compress(Bitmap.CompressFormat.Png, 100, os);
    }
    b.Dispose ();

    var imageUri = Android.Net.Uri.Parse ($"file://{sdCardPath}/{tempFilename}");
    var sharingIntent = new Intent ();
    sharingIntent.SetAction (Intent.ActionSend);
    sharingIntent.SetType ("image/*");
    sharingIntent.PutExtra (Intent.ExtraText, content);
    sharingIntent.PutExtra (Intent.ExtraStream, imageUri);
    sharingIntent.AddFlags (ActivityFlags.GrantReadUriPermission);
    StartActivity (Intent.CreateChooser (sharingIntent, title));
}

同时为您的应用添加 ReadExternalStorage 和 WriteExternalStorage 权限。

如果可行，请告诉我。

Answer 2

我已经为 twitter 和 fb 实现了共享。 您可以使用本机 facebook ShareDialog and if isn't available use OAuth2Authenticator to get access token then post using FB graph 并使用 OAuth1Authenticator 在 Twitter 上摆姿势

public void ShareViaSocial(string serviceType, string urlToShare)
        {
            ShareDialog di = new ShareDialog(MainActivity.Instance);
             var facebookShareContent = new ShareLinkContent.Builder();
             facebookShareContent.SetContentUrl(Android.Net.Uri.Parse(urlToShare));
            if (serviceType == "Facebook")
            {
                if (di.CanShow(facebookShareContent.Build(), ShareDialog.Mode.Automatic))
                {
                    di.Show(facebookShareContent.Build());
                }
                else
                {
                    var auth = new OAuth2Authenticator(
                    clientId: 'ClientId',
                    scope: "public_profile,publish_actions",
                    authorizeUrl: new Uri("https://m.facebook.com/dialog/oauth/"),
                    redirectUrl: new Uri( "http://www.facebook.com/connect/login_success.html"));

                    MainActivity.Instance.StartActivity(auth.GetUI(MainActivity.Instance.ApplicationContext));

                    auth.AllowCancel = true;
                    auth.Completed += (s, e) =>
                    {
                        if (e.IsAuthenticated)
                        {
                            Account fbAccount = e.Account;
                            Dictionary<string, string> dictionaryParameters = new Dictionary<string, string>() { { "link", urlToShare } };
                            var requestUrl = new Uri("https://graph.facebook.com/me/feed");
                            var request = new OAuth2Request(SharedConstants.requestMethodPOST, requestUrl, dictionaryParameters, fbAccount);

                            request.GetResponseAsync().ContinueWith(this.requestResult);
                        }
                        else { OnShare(this, ShareStatus.NotSuccessful); }
                    };
                    auth.Error += Auth_Error;
                }
            }

            else
            {
                var auth = new OAuth1Authenticator(
                               'TwitterConsumerKey',
                               'TwitterConsumerSecret',
                               new Uri("https://api.twitter.com/oauth/request_token"),
                               new Uri("https://api.twitter.com/oauth/authorize"),
                               new Uri("https://api.twitter.com/oauth/access_token"),
                               new Uri('TwitterCallBackUrl'));

                auth.AllowCancel = true;
                // auth.ShowUIErrors = false;
                // If authorization succeeds or is canceled, .Completed will be fired.
                auth.Completed += (s, e) =>
                {
                    // We presented the UI, so it's up to us to dismiss it.

                    if (e.IsAuthenticated)
                    {
                        Account twitterAccount = e.Account;
                        Dictionary<string, string> dictionaryParameters = new Dictionary<string, string>() { { "status", urlToShare } };
                        var request = new OAuth1Request(SharedConstants.requestMethodPOST, new Uri("https://api.twitter.com/1.1/statuses/update.json"), dictionaryParameters, twitterAccount);
                        //for testing var request = new OAuth1Request("GET",new Uri("https://api.twitter.com/1.1/account/verify_credentials.json "),null, twitterAccount);
                        request.GetResponseAsync().ContinueWith(this.requestResult);
                    }
                    else { OnShare(this, ShareStatus.NotSuccessful); }
                };
                auth.Error += Auth_Error;
                //auth.IsUsingNativeUI = true;
                MainActivity.Instance.StartActivity(auth.GetUI(MainActivity.Instance.ApplicationContext));
            }


        }