自从上次做完视频播放器调研以后，心里就知道，肯定以后这块东西都是我做，果不其然，公司对视频播放这块不断的优化。我就悲催的无限填坑，话说英语差，看国外文档真的很吃力。
简单讲一下项目中遇到的问题。

• 创建和基本使用
  这个不多讲，最简单使用就是布局里

 <com.google.android.exoplayer2.ui.PlayerView
                android:id="@+id/videoview"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                app:surface_type="texture_view"
                app:use_controller="false" />

接下来创建轨道，播放器等，如果你播放的时候发现有时候黑屏。这是可能你的VideoCache不是单例模式。 下面是我自己写的Manger和VideoCache

public class ExoPlayerManger {
    private static final String TAG = "ExoPlayerManger";
    private Context mContext;
    private  BandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
    // 创建轨道选择工厂
    private TrackSelection.Factory videoTrackSelectionFactory = new AdaptiveTrackSelection.Factory(bandwidthMeter);
    // 创建轨道选择器实例
    private TrackSelector trackSelector = new DefaultTrackSelector(videoTrackSelectionFactory);
    private SimpleExoPlayer simpleExoPlayer;
    private DataSource.Factory dataSourceFactory;
    private String mVideoUrl;
    private SimpleCache simpleCache;
    private Uri playVideoUri;
    private ExtractorMediaSource mediaSource;


    /**
     * @param context 传入context
     */
    public void setBuilderContext(Context context) {
        mContext = context;
        dataSourceFactory = new DefaultDataSourceFactory(mContext, "seyed");
    }

    /**
     * @param videoUrl 传入视频路径
     */
    public void setVideoUrl(String videoUrl) {
        this.mVideoUrl = videoUrl;
        simpleCache = VideoCache.getInstance(mContext);
        playVideoUri = Uri.parse(mVideoUrl);
    }


    /**
     * @return 返回exoPlayer对象
     */
    public SimpleExoPlayer create() {
        try {
            simpleExoPlayer = ExoPlayerFactory.newSimpleInstance(mContext, trackSelector);
            dataSourceFactory = new CacheDataSourceFactory(simpleCache, dataSourceFactory);
            mediaSource = new ExtractorMediaSource.Factory(dataSourceFactory).createMediaSource(playVideoUri);
            simpleExoPlayer.prepare(mediaSource);

        } catch (Exception e) {

        }
        return simpleExoPlayer;
    }


}

/**
 * @author ：leo on 2018/12/17 17:58
 * <p>
 * 方法用途 ：视频缓存单例模式
 */
public class VideoCache {
    private static SimpleCache sDownloadCache;

    /**
     * @param context
     * @return
     */
    public static SimpleCache getInstance(Context context) {
        if (sDownloadCache == null) {
            sDownloadCache = new SimpleCache(new File(getMediaCacheFile(context), "StoryCache"), new LeastRecentlyUsedCacheEvictor(512 * 1024 *1024));

        }
        return sDownloadCache;
    }

    public static File getMediaCacheFile(Context context) {
        String directoryPath = "";
        String childPath = "exoPlayer";
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            // 外部储存可用
            directoryPath = File.separator + context.getExternalFilesDir(childPath).getAbsolutePath();
        } else {
            directoryPath = File.separator + context.getFilesDir().getAbsolutePath() + File.separator + childPath;
        }
        File file = new File(directoryPath);
        //判断文件目录是否存在
        if (!file.exists()) {
            file.mkdirs();
        }

        return file;
    }


}

紧接着 只需要

ExoPlayerManger exoPlayerManger = new ExoPlayerManger();
        exoPlayerManger.setBuilderContext(mContext);
        exoPlayerManger.setVideoUrl(playVideoUrl);
        simpleExoPlayer = exoPlayerManger.create();
        //设置音量  测试期间设置为0
        simpleExoPlayer.setVolume(10);
        videoView.setPlayer(simpleExoPlayer);
        //赋值给显示时间
        simpleExoPlayer.addListener(this);
      //开启播放
        simpleExoPlayer.setPlayWhenReady(true);

播放器有个监听 Player.EventListener ，这就讲几个状态

@Override
    public void onPlayerStateChanged(boolean playWhenReady, int playbackState) {
        if (isFullScreen) {
            fullScreenDialog.setPlayState(playbackState);
        }
        switch (playbackState) {
        //缓冲状态
            case 2:
                break;
            //播放状态
            case 3:
             
                break;
            //播放完成
            case 4:
               
            default:
                break;
        }

• 如何播放raw下文件
  RawResourceDataSource.buildRawResourceUri(R.raw.login_bg_video);

        ExoPlayerManger exoPlayerManger = new ExoPlayerManger();
        exoPlayerManger.setBuilderContext(getContext());
//设置从raw下读取的文件路径
   exoPlayerManger.setVideoUrl(RawResourceDataSource.buildRawResourceUri(R.raw.login_bg_video).toString());
        simpleExoPlayer = exoPlayerManger.create();
        simpleExoPlayer.setVolume(0);
        simpleExoPlayer.setRepeatMode(1);
        playerView.setPlayer(simpleExoPlayer);

//        simpleExoPlayer.prepare(audioSource);

        simpleExoPlayer.setPlayWhenReady(true);

• 列表中点击切换到全屏
  这里有很多方法，我选择的方法不是最好的。科学上网看了很多老外写的例子，大部分都是弹出一个Dialog，将item中的播放PlayerView，remove出来，放到Dialog里面。然后更改PlayerView的布局大小就可以了。
  但是这里会有一个卡顿问题，老外同学们基本没讲，如果你按照直接removeView然后addView to Dialog, 我测试基本会卡1-5s。这时候可以做一个骚操作，就是向前或者向后seekto一下，可以基本做到秒开。当你切换窗口的时候，可以将PlayerView 还回去就可以了，记得设置原来的宽高和大小。

 //从当前布局移除播放view
        ViewGroup parent = (ViewGroup) videoView.getParent();
        if (parent != null) {
            parent.removeView(videoView);
        }

//加入到Dialog
 ViewGroup.LayoutParams layoutParams = videoView.getLayoutParams();
        layoutParams.width = RelativeLayout.LayoutParams.MATCH_PARENT;
        layoutParams.height = RelativeLayout.LayoutParams.MATCH_PARENT;
        videoView.setLayoutParams(layoutParams);
        rlShow.addView(playerView);

其实也可以尝试使用，simpleExoPlayer.setVideoTextureView();切换画布，但是我在测试的时候，会有卡顿，有时间的同学可以试试，希望你有别的办法可以给我留言，谢谢。还有很多细节的东西，等我想起来再补上，连续加班，今天才有时间写点东西，就先到这里 。

最近公司大佬提出建议，说来回切换全屏的时候有卡顿经过一番百度谷姐，终于找到解决办法。
使用TextureView 作为ExoPlayer播放画布。
TextureView 在切换状态的时候会经历销毁重建过程。
那么之前TextureView中播放的SurfaceTexture也会销毁。
建议在从列表到全屏之前调用TextureView.getSurfaceTexture()
保存当前状态，在设置完新的宽高后，将保存的SurfaceTexture重新设置进去。
这里会有一个坑，就是设置进去也会卡在那里。
在调用TextureView.getSurfaceTexture()之前，给TextureView设置setSurfaceTextureListener 并在onSurfaceTextureDestroyed方法中返回false
在onSurfaceTextureAvailable中重新调用textureView.setSurfaceTexture(mSurfaceTexture);
建议try一下，因为可能会报SurfaceTexture IsReleased 异常。
简单代码如下

 windowTextureView.setSurfaceTextureListener(new TextureView.SurfaceTextureListener() {
            @Override
            public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
            }

            @Override
            public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {

            }

            @Override
            public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
                return false;
            }

            @Override
            public void onSurfaceTextureUpdated(SurfaceTexture surface) {

            }
        });
 //获取当前缓存的帧
        SurfaceTexture surfaceTexture = windowTextureView.getSurfaceTexture();
//跳转全屏
        fullScreenDialog.setFullScreenRes(windowTextureView, surfaceTexture);

//在全屏页面中
            textureView.setSurfaceTextureListener(new TextureView.SurfaceTextureListener() {
                @Override
                public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {

                    if (mSurfaceTexture == null) {
                        mSurfaceTexture = surface;
                    }
                    try {
                        textureView.setSurfaceTexture(mSurfaceTexture);
                    } catch (Exception e) {

                    }


                }

                @Override
                public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {

                }

                @Override
                public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
                    return false;
                }

                @Override
                public void onSurfaceTextureUpdated(SurfaceTexture surface) {

                }
            });

经过测试基本可以实现无卡顿切换。