Question

我为iOS和Android制作应用程序，提供观看视频的能力。我目前正在开发iOS实现，但每次我解除持有AVPlayer或MPPlayer的viewcontroller时，应用程序抛出'System.InvalidOperationException：Sequence不包含匹配元素'。我不知道为什么会这样。我会分享一些示例代码。

渲染

    using AnimeViewer.iOS.CustomRenderers;
    using AnimeViewer.Views.Partials;
    using AVFoundation;
    using Foundation;
    using UIKit;
    using Xamarin.Forms;
    using Xamarin.Forms.Platform.iOS;

    [assembly: ExportRenderer(typeof(VideoPlayer), typeof(VideoPlayerRenderer))]

    namespace AnimeViewer.iOS.CustomRenderers
    {
         public class VideoPlayerRenderer : ViewRenderer<VideoPlayer, UIView>
    {
        public VideoPlayer VideoPlayer { get; set; }

        protected override void OnElementChanged(ElementChangedEventArgs<VideoPlayer> e)
        {
            base.OnElementChanged(e);

            if (e.NewElement == null) return;
            VideoPlayer = e.NewElement;
            SetNativeControl(new UIView {Frame = UIScreen.MainScreen.Bounds});

            var player = new AVPlayer(new NSUrl(VideoPlayer.Source));
            var playerLayer = new AVPlayerLayer
            {
                Player = player,
                Frame = Control.Frame
            };
            Control.Layer.AddSublayer(playerLayer);
            player.Play();
        }
    }
}

查看

<?xml version="1.0" encoding="utf-8"?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:partials="clr-namespace:AnimeViewer.Views.Partials;assembly=AnimeViewer"
             x:Class="AnimeViewer.Views.VideoPlayerPage">
    <partials:VideoPlayer x:Name="Player"
                          HorizontalOptions="FillAndExpand"
                          VerticalOptions="FillAndExpand" />
</ContentPage>

Answer 1

您不需要自定义渲染器来调用视频播放器，您可以使用DependencyService：

public class VideoPLayer : IVideoPlayer
{
    public void Play(string path)
    {
        var _player = new AVPlayer(NSUrl.FromFilename(path));
        var _playerController = new AVPlayerViewController();
        _playerController.Player = _player;

        var window = UIApplication.SharedApplication.KeyWindow;
        var vc = window.RootViewController;
        while (vc.PresentedViewController != null)
        {
            vc = vc.PresentedViewController;
        }

        vc.PresentViewController(_playerController, true, null);
        _playerController.View.Frame = vc.View.Frame;
    }
}

要了解有关DependencyService的更多信息，您可以访问以下链接：https://developer.xamarin.com/guides/xamarin-forms/dependency-service/

Video Player在Xamarin Forms中引发System.InvalidOperationException：Sequence不包含匹配的元素

1 个答案: