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。

我尝试安装 XLab 并使用它的示例代码，但它有例外。例如，对于 XLabs 示例，我使用以下内容：

/// <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>(): IResolver has not been set. Please set it by calling Resolver.SetResolver(resolver)

上得到以下异常

如何使用这个或其他替代方法与 Xamarin.Forms 拍照？感谢提前提示！

Answer 1

您必须配置 IoC 才能使其正常工作，并使用 Resolver.SetResolver 方法将 IoC 提供程序设置为解析器。在这里阅读更多，https://github.com/XLabs/Xamarin-Forms-Labs/wiki/IOC

Answer 2

您无法直接访问 Xamarin.Forms 中的本机功能。您必须使用 Dependency Service 才能访问本机功能，例如访问 Camrera、音频等

试试这个：http://developer.xamarin.com/guides/cross-platform/xamarin-forms/dependency-service/

Answer 3

这是 xLabs 相机的示例代码：
https://www.dropbox.com/s/9paojg1q43ahnqk/XPA_PickMedia_XLabs_XFP.zip?dl=0 从这里的论坛找到它：https://forums.xamarin.com/discussion/35636/a-sample-project-using-camera-control-mediapicker-of-xlabs

Answer 4

在你的Droid Project中添加classMainActivity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
    ....
}

并在 IOS class AppDelegate 这个：

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
    ....
}

在 Xamarin.Forms 中访问相机

Access to Camera in Xamarin.Forms

c#

camera

xamarin.forms

xlabs