使用 Xamarin Forms 共享图像

Question

我创建了一个 Xamarin Forms (PCL) 解决方案，目前我专注于 Android 项目。我正在尝试使用依赖服务实现图像共享。图像位于 Android 项目的 drawable 文件夹中。但是，每次运行下面的代码时，应用程序都会崩溃：发生未处理的异常。我检查了输出日志，但没有什么特别之处。是否有人能够查看我的代码并告诉我其中是否有错误？

非常感谢

界面：

public interface IShare
{
    void Share(ImageSource imageSource);
}

Xml：

<ContentPage.Content>
    <Image x:Name="LogoImage" Source="icon.png"/>
</ContentPage.Content>

代码隐藏：

private void Action_Clicked(object sender, EventArgs e)
{
    DependencyService.Get<IShare>().Share(LogoImage.Source);
}

ShareClass（在Android项目中）：

[assembly: Dependency(typeof(ShareClass))]
namespace MyProject.Droid
{
    public class ShareClass : Activity, IShare
    {
        public async void Share(ImageSource imageSource)
        {
            var intent = new Intent(Intent.ActionSend);
            intent.SetType("image/png");

            var handler = new ImageLoaderSourceHandler();
            var bitmap = await handler.LoadImageAsync(imageSource, this);

            var path = Android.OS.Environment.GetExternalStoragePublicDirectory(Android.OS.Environment.DirectoryDownloads
                + Java.IO.File.Separator + "logo.png");

            using (var os = new System.IO.FileStream(path.AbsolutePath, FileMode.Create))
            {
                bitmap.Compress(Bitmap.CompressFormat.Png, 100, os);
            }

            intent.PutExtra(Intent.ExtraStream, Android.Net.Uri.FromFile(path));
            Forms.Context.StartActivity(Intent.CreateChooser(intent, "Share Image"));

        }
    }
}

Answer 1

这是我用于 ShareClass 的代码，以最终实现共享意图，希望它对某人有所帮助：

[assembly: Xamarin.Forms.Dependency(typeof(ShareClass))]
namespace MyProject.Droid
{
public class ShareClass: MainActivity, IShare
{
    public async void Share(ImageSource imageSource)
    {
        var intent = new Intent(Intent.ActionSend);

        intent.SetType("image/jpeg");

        IImageSourceHandler handler;

        if (imageSource is FileImageSource)
        {
            handler = new FileImageSourceHandler();
        }
        else if (imageSource is StreamImageSource)
        {
            handler = new StreamImagesourceHandler(); // sic
        }
        else if (imageSource is UriImageSource)
        {
            handler = new ImageLoaderSourceHandler(); // sic
        }
        else
        {
            throw new NotImplementedException();
        }

        var bitmap = await handler.LoadImageAsync(imageSource, CrossCurrentActivity.Current.Activity);

        Java.IO.File path = Android.OS.Environment.GetExternalStoragePublicDirectory(Android.OS.Environment.DirectoryDownloads
            + Java.IO.File.Separator + "MyDiagram.jpg");

        using (System.IO.FileStream os = new System.IO.FileStream(path.AbsolutePath, System.IO.FileMode.Create))
        {
            bitmap.Compress(Bitmap.CompressFormat.Jpeg, 100, os);
        }

        intent.AddFlags(ActivityFlags.GrantReadUriPermission);
        intent.AddFlags(ActivityFlags.GrantWriteUriPermission);
        intent.PutExtra(Intent.ExtraStream, FileProvider.GetUriForFile(CrossCurrentActivity.Current.Activity, "com.mypackagename.fileprovider", path));

        CrossCurrentActivity.Current.Activity.StartActivity(Intent.CreateChooser(intent, "Share Image"));
    }
}
}