c# - 使用 Xamarin Forms 播放视频

Question

我们正在使用 Xamarin.forms 在 Xamarin 中构建应用程序。在应用程序中，我们需要播放视频，因此我们为此编写了一些代码。但是，视频没有播放，并且在 Android 上应用程序崩溃并抛出一般错误。

这是代码:

VideoContainer.cs

using System;
using Xamarin.Forms;
using System.Collections.Generic;

namespace MyApp
{
    public class VideoView : View
    {
        public Action StopAction;
        public VideoView ()
        {
            Console.WriteLine("VideoView loaded");
        }

        public static readonly BindableProperty FileSourceProperty = 
            BindableProperty.Create<VideoView,string>(
                p => p.FileSource,string.Empty);

        public string FileSource {
            get { return (string)GetValue (FileSourceProperty); }
            set { SetValue (FileSourceProperty, value); }
        }

        public void Stop(){
            if(StopAction != null)
                StopAction ();
        }
    }
}

VideoViewRender.cs

using System.Text;

using Android.App;
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;
using Android.Media;
using Android.Content.Res;
using Java.Lang;
using MyApp.Droid;

[assembly: ExportRenderer(typeof(VideoView), typeof(VideoViewRenderer))]
//
namespace MyApp.Droid
{
    public class VideoViewRenderer : ViewRenderer
    {
        VideoView videoview;
        MediaPlayer player;
        MediaController mediaController;
        Handler handler = new Handler();
        public VideoViewRenderer()
        {
            Console.WriteLine("VideoViewRenderer loaded");
        }   

        public void SurfaceChanged(ISurfaceHolder holder, global::Android.Graphics.Format format, int width, int height)
        {

        }

        public void SurfaceDestroyed(ISurfaceHolder holder)
        {

        }

        void play(string fullPath)
        {
            AssetFileDescriptor afd = Forms.Context.Assets.OpenFd(fullPath);
            if (afd != null)
            {

                player.SetDataSource(afd.FileDescriptor, afd.StartOffset, afd.Length);
                player.Prepare();
                player.Start();
                Control.Layout(0, 200, 400, 600);
                player.Pause();


            }
        }

        public void SurfaceCreated(ISurfaceHolder holder)
        {
            player.SetDisplay(holder);
        }

        public override bool OnTouchEvent(MotionEvent e)
        {
            mediaController.Show();
            return false;
        }

        //--MediaPlayerControl methods----------------------------------------------------
        public void Start()
        {
            player.Start();
        }


        public void Pause()
        {
            player.Pause();
        }

        public int Duration
        {
            get
            {
                return player.Duration;
            }
        }

        public int CurrentPosition
        {
            get
            {
                return player.CurrentPosition;
            }
        }

        public void SeekTo(int i)
        {
            player.SeekTo(i);
        }

        public bool IsPlaying
        {
            get
            {
                return player.IsPlaying;
            }
        }

        public int BufferPercentage
        {
            get
            {
                return 0;
            }
        }

        public int AudioSessionId
        {
            get
            {
                return 0;
            }
        }

        public bool CanPause()
        {
            return true;
        }

        public bool CanSeekBackward()
        {
            return true;
        }

        public bool CanSeekForward()
        {
            return true;
        }
        //--------------------------------------------------------------------------------

    }
}

发生的情况是 VideoView loaded 被记录到控制台，但 VideoViewRenderer loaded 没有。我们从 the Xamarin forum 获得了这段代码, 但未能成功实现。我们做错了什么？

Answer 1

我认为您的 [assembly:...] 弄错了 VideoView。

有可能 ExportRenderer 得到 Android.VideoView。

你应该得到 [assembly: ExportRenderer(typeof(MyApp.VideoView), typeof(MyApp.Droid.VideoView))]。