Android TextureView实现视频播放的方法

一、什么是TextureView

TextureView是Android 4.0（API level 14）引入的一个新的控件，它可以在UI线程之外维护一个可渲染的surface，这允许我们可以将播放视频这样复杂的任务放到子线程中去执行，从而提高程序的性能。相较于SurfaceView，在TextureView中我们可以使用TextureView.setTransform()方法来对视频进行旋转、移动等的变换操作。但是使用TextureView也有一些限制，比如只有在硬件加速开启的情况下才有效，并且在TextureView上不能覆盖其他View。

二、使用TextureView播放视频

我们还需要使用MediaPlayer来进行视频的播放。在UI布局文件中，我们可以如下声明TextureView和一个Button控件：

    <TextureView
        android:id="@+id/textureView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <Button
        android:id="@+id/startBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="开始播放" />

在Java代码中，我们可以通过如下代码来初始化MediaPlayer和TextureView：

    private MediaPlayer mediaPlayer;
    private TextureView textureView;
    private Button startBtn;
    
    private void initView() {
        textureView = findViewById(R.id.textureView);
        startBtn = findViewById(R.id.startBtn);
        
        // 初始化MediaPlayer并设置监听器
        mediaPlayer = new MediaPlayer();
        mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
        mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
            @Override
            public void onPrepared(MediaPlayer mp) {
                mediaPlayer.start();  // 开始播放视频
            }
        });
        
        // 设置TextureView的监听器
        textureView.setSurfaceTextureListener(new TextureView.SurfaceTextureListener() {
            @Override
            public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
                mediaPlayer.setSurface(new Surface(surface));
                try {
                    mediaPlayer.setDataSource("video.mp4");  // 视频文件的路径
                    mediaPlayer.prepareAsync();  // 异步加载视频
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            
            @Override
            public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
            }
            
            @Override
            public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
                mediaPlayer.stop();  // 销毁TextureView时停止播放视频
                mediaPlayer.release();
                return true;
            }
            
            @Override
            public void onSurfaceTextureUpdated(SurfaceTexture surface) {
            }
        });
        
        startBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mediaPlayer.start();  // 点击按钮开始播放
            }
        });
    }

三、将TextureView与RecyclerView联动

在某些场景下，我们需要将TextureView与RecyclerView联动，实现类似于社交软件中的视频滚动浏览效果。

在我们的RecyclerView的Adapter中，需要为每个TextureView设置一个SurfaceTextureListener。在onBindViewHolder()方法中，我们可以创建一个新的MediaPlayer，为它设置数据源和回调监听，以及为TextureView设置SurfaceTextureListener。在onViewRecycled()方法中，我们需要释放MediaPlayer所占用的资源。

public class VideoAdapter extends RecyclerView.Adapter<VideoViewHolder> {

    private List<String> videoList;
    private MediaPlayer mediaPlayer;
    private TextureView.SurfaceTextureListener surfaceTextureListener;

    public VideoAdapter(List<String> videoList) {
        this.videoList = videoList;
        mediaPlayer = new MediaPlayer();
        surfaceTextureListener = createSurfaceTextureListener();
    }

    @NonNull
    @Override
    public VideoViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        // 创建ViewHolder
    }

    @Override
    public void onBindViewHolder(@NonNull VideoViewHolder holder, int position) {
        TextureView textureView = holder.getTextureView();
        textureView.setSurfaceTextureListener(surfaceTextureListener);
        String videoUrl = videoList.get(position);
        try {
            mediaPlayer.setDataSource(videoUrl);
            mediaPlayer.prepareAsync();
            mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
                @Override
                public void onPrepared(MediaPlayer mp) {
                    mp.start();
                }
            });
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onViewRecycled(@NonNull VideoViewHolder holder) {
        TextureView textureView = holder.getTextureView();
        mediaPlayer.stop();
        mediaPlayer.reset();
        textureView.setSurfaceTextureListener(null);
    }

    @Override
    public int getItemCount() {
        return videoList.size();
    }

    private TextureView.SurfaceTextureListener createSurfaceTextureListener() {
        return new TextureView.SurfaceTextureListener() {
            @Override
            public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
                mediaPlayer.setSurface(new Surface(surface));
            }

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

            }

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

            @Override
            public void onSurfaceTextureUpdated(SurfaceTexture surface) {

            }
        };
    }
}