Android TextureView實現視頻播放的方法

一、什麼是TextureView

TextureView是Android 4.0（API level 14）引入的一個新的控制項，它可以在UI線程之外維護一個可渲染的surface，這允許我們可以將播放視頻這樣複雜的任務放到子線程中去執行，從而提高程序的性能。相較於SurfaceView，在TextureView中我們可以使用TextureView.setTransform()方法來對視頻進行旋轉、移動等的變換操作。但是使用TextureView也有一些限制，比如只有在硬體加速開啟的情況下才有效，並且在TextureView上不能覆蓋其他View。

二、使用TextureView播放視頻

我們還需要使用MediaPlayer來進行視頻的播放。在UI布局文件中，我們可以如下聲明TextureView和一個Button控制項：

    <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="開始播放" />

在Java代碼中，我們可以通過如下代碼來初始化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並設置監聽器
        mediaPlayer = new MediaPlayer();
        mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
        mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
            @Override
            public void onPrepared(MediaPlayer mp) {
                mediaPlayer.start();  // 開始播放視頻
            }
        });
        
        // 設置TextureView的監聽器
        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");  // 視頻文件的路徑
                    mediaPlayer.prepareAsync();  // 非同步載入視頻
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            
            @Override
            public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
            }
            
            @Override
            public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
                mediaPlayer.stop();  // 銷毀TextureView時停止播放視頻
                mediaPlayer.release();
                return true;
            }
            
            @Override
            public void onSurfaceTextureUpdated(SurfaceTexture surface) {
            }
        });
        
        startBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mediaPlayer.start();  // 點擊按鈕開始播放
            }
        });
    }

三、將TextureView與RecyclerView聯動

在某些場景下，我們需要將TextureView與RecyclerView聯動，實現類似於社交軟體中的視頻滾動瀏覽效果。

在我們的RecyclerView的Adapter中，需要為每個TextureView設置一個SurfaceTextureListener。在onBindViewHolder()方法中，我們可以創建一個新的MediaPlayer，為它設置數據源和回調監聽，以及為TextureView設置SurfaceTextureListener。在onViewRecycled()方法中，我們需要釋放MediaPlayer所佔用的資源。

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) {
        // 創建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) {

            }
        };
    }
}