c# - 在 Xamarin.Forms 中访问相机

Question

我需要使用 Xamarin Forms PCL 访问相机。我找不到任何有效的样本。

我尝试通过安装 XLab并使用其示例代码，但它有异常(exception)。例如，对于 XLabs 示例，我使用了以下内容:

/// <summary>
/// Takes the picture.
/// </summary>
/// <returns>Take Picture Task.</returns>
internal async Task<MediaFile> TakePicture()
{
    Setup();

    ImageSource = null;

    return await _mediaPicker.TakePhotoAsync(new CameraMediaStorageOptions { DefaultCamera = CameraDevice.Front, MaxPixelDimension = 400 }).ContinueWith(t =>
    {
        if (t.IsFaulted)
        {
            Status = t.Exception.InnerException.ToString();
        }
        else if (t.IsCanceled)
        {
            Status = "Canceled";
        }
        else
        {
            var mediaFile = t.Result;

            ImageSource = ImageSource.FromStream(() => mediaFile.Source);

            return mediaFile;
        }

        return null;
    }, _scheduler);
}

/// <summary>
/// Setups this instance.
/// </summary>
private void Setup()
{
    if (_mediaPicker != null)
    {
        return;
    }

    var device = Resolver.Resolve<IDevice>();

    ////RM: hack for working on windows phone? 
    _mediaPicker = DependencyService.Get<IMediaPicker>() ?? device.MediaPicker;
}

我在 Resolver.Resolve<IDevice>(): 上得到以下异常IResolver has not been set. Please set it by calling Resolver.SetResolver(resolver)

我如何使用这个或其他替代方案来使用 Xamarin.Forms 拍照？感谢您提前提供任何提示!

Answer 1

在你的Droid Project中添加MainActivity类这段代码

protected override void OnCreate (Bundle bundle)
{
    base.OnCreate (bundle);
    #region Resolver Init
    SimpleContainer container = new SimpleContainer();
    container.Register<IDevice>(t => AndroidDevice.CurrentDevice);
    container.Register<IDisplay>(t => t.Resolve<IDevice>().Display);
    container.Register<INetwork>(t => t.Resolve<IDevice>().Network);

    Resolver.SetResolver(container.GetResolver());
    #endregion
    ....
}

在 IOS 类 AppDelegate 中:

public override bool FinishedLaunching(UIApplication app, NSDictionary options)
{
    #region Resolver Init
    SimpleContainer container = new SimpleContainer();
    container.Register<IDevice>(t => AppleDevice.CurrentDevice);
    container.Register<IDisplay>(t => t.Resolve<IDevice>().Display);
    container.Register<INetwork>(t => t.Resolve<IDevice>().Network);

    Resolver.SetResolver(container.GetResolver());
    #endregion
    ....
}