Android MediaPlayer 在 6.0 以上版本使用倍速播放功能說明

Android MediaPlayer 在API 23即6.0版本開始支持倍速播放，下面咱們來介紹一下如何使用MediaPlayer進行倍速播放。

1、核心接口

MediaPlayer.setPlaybackParams(PlaybackParams params) throws IllegalStateException, IllegalArgumentException

1. 接口說明

(1) 使用這個接口能夠進行播放速率的設置。
(2) 播放器prepared狀態以前調用這個方法不會更改播放器的狀態。
(3) prepared狀態以後設置速率0等同於調用pause()，當調用start恢復播放之後，將以原來的速率進行播放。
(4) prepared狀態以後設置非0的速率等同於調用start()。
(5) 當播放器還未初始化或者已經被釋放的時候設置會拋IllegalStateException的異常。
(6) 當參數不支持的時候會拋IllegalArgumentException的異常。

2. 設置時機要求

合法的時機：Initialized, Prepared, Started, Paused, PlaybackCompleted, Error
非法的時機：Idle, Stopped

2、使用示例

本例爲懸浮彈窗播放View，在此基礎上增長了倍速播放的測試邏輯，經測試，發現此API可用，且效果基本和ijk播放器同樣。

public class FloatingPopupWindow implements SurfaceHolder.Callback {

    // 彈窗寬度
    private static final int POPUP_WINDOW_WIDTH = 567;

    // 彈窗高度
    private static final int POPUP_WINDOW_HEIGHT = 432;

    private Context mContext;

    private PopupWindow mPopupWindow;

    private View mPopContentView;

    private RelativeLayout mFloatingLayout;

    SurfaceView surfaceView;

    SurfaceHolder surfaceHolder;

    MediaPlayer mediaPlayer;

    private boolean IsDouble = false;
    private float lastX;
    private float lastY;

    public FloatingPopupWindow(Context context) {
        mContext = context;
        mPopContentView = LayoutInflater.from(mContext).inflate(R.layout.popup_window_floating, null);
        mPopupWindow = new PopupWindow(mPopContentView, POPUP_WINDOW_WIDTH, POPUP_WINDOW_HEIGHT);
        mFloatingLayout = mPopContentView.findViewById(R.id.floating_layout);
        surfaceView = mPopContentView.findViewById(R.id.surface_view);
        surfaceHolder = surfaceView.getHolder();
        surfaceHolder.addCallback(this);
        mPopContentView.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                switch (event.getAction()) {
                    case MotionEvent.ACTION_DOWN:
                        if (event.getPointerCount() == 1) {
                            IsDouble = false;
                        }
                        if (!IsDouble) {
                            lastX = event.getRawX();
                            lastY = event.getRawY();
                        }
                        break;
                    case MotionEvent.ACTION_MOVE:
                        if (event.getPointerCount() > 1) {
                            IsDouble = true;
                        }
                        if (!IsDouble) {
                            int deltaX = (int) (event.getRawX() - lastX);
                            lastX = event.getRawX();
                            int deltaY = (int) (event.getRawY() - lastY);
                            lastY = event.getRawY();
                            mPopupWindow.update(deltaX + (int) lastX - (POPUP_WINDOW_WIDTH / 2), deltaY + (int) lastY - (POPUP_WINDOW_HEIGHT / 2), -1, -1, true);
                        }
                        break;
                }
                return true;
            }
        });
        mediaPlayer = new MediaPlayer();
    }

    /**
     * 是否顯示
     */
    public boolean isShowing() {
        return mPopupWindow.isShowing();
    }

    public void setPlayPath(String playPath) {
        try {
            mediaPlayer.reset();
            mediaPlayer.setDataSource(playPath);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        Surface surface = holder.getSurface();
        mediaPlayer.setSurface(surface);
        mediaPlayer.prepareAsync();

        mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
            @Override
            public void onPrepared(MediaPlayer mp) {
                mp.start();
                // 6.0及之後支持倍速，測試
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                    mp.setPlaybackParams(new PlaybackParams().setSpeed(0.75f));
                }
            }
        });

        mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
            @Override
            public void onCompletion(MediaPlayer mp) {
                dismiss();
            }
        });
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {

    }

    private View mNowView;  // 當前容器裏面裝載的View

    /**
     * 添加新View
     */
    public void addView(View view) {
        mNowView = view;
        if (mFloatingLayout != null) {
            mFloatingLayout.addView(view);
        }
    }

    /**
     * 獲取當前正展現的View
     */
    public View getNowView() {
        return mNowView;
    }

    /**
     * 移除全部的子佈局
     */
    public void removeAllView() {
        if (mFloatingLayout != null) {
            mFloatingLayout.removeAllViews();
        }
    }

    /**
     * 顯示彈出框
     */
    public void show(View view) {
        if (isShowing()) {
            return;
        }
        mPopupWindow.showAtLocation(view, Gravity.NO_GRAVITY, 0, 200);
    }

    /**
     * 隱藏彈出框
     */
    public void dismiss() {
        if (mPopupWindow != null) {
            if (mPopupWindow.isShowing()) {
                mPopupWindow.dismiss();
            }
        }
    }
}