1、前言

上一篇文章我们介绍了SurfaceView和TextureView的基础知识点；

SurfaceView 以及 TextureView 均继承于 android.view.View，属于 Android 提供的控件体系的一部分。与普通 View 不同，它们都在独立的线程中绘制和渲染。所以，相比于普通的 ImageView 它们的性能更高，因此常被用在对绘制的速率要求比较高的应用场景中，用来解决普通 View 因为绘制的时间延迟而带来的掉帧的问题，比如用作相机预览、视频播放的媒介等；

今天我们就来简单的用TextureView封装下视频播放器；

2、视频播放器方案介绍

1.videoView+mediaPlayer

videoView继承自SurfaceView。surfaceView是在现有View上创建一个新的Window，

内容显示和渲染是在新的Window中，这使得SurfaceView的绘制和刷新可以在单独的线程中进行。

由于SurfaceView的内容是在新建的Window中，这使得SurfaceView不能放在RecyclerView或ScrollView中，一些View中的特性也无法使用。

2.textureView+mediaPlayer

textureView不会创建新的窗口，它的使用跟其他普通View一样。

考虑到以后的可扩展性，最终采用这个方案

3.为什么使用TextureView

TextureView是在4.0(API level 14)引入的，与SurfaceView相比，它不会创建新的窗口来显示内容。它是将内容流直接投放到View中，并且可以和其它普通View一样进行移动，旋转，缩放，动画等变化。TextureView必须在硬件加速的窗口中使用。

3、TextureView使用介绍

1.TextureView被创建后不能直接使用，必须将其添加到ViewGroup中。

2.TextureView必须要等SurfaceTexture准备就绪才能起作用，这里通常需要给TextureView设置监听器SurfaceTextureListener。等待onSurfaceTextureAvailable回调后，才能使用

3.TextureView创建和初始化

 //初始化一个TextureView并添加至ViewGroup或找到你的TextureView 组件   mTextureView=new TextureView(getContext());   //设置画布监听   textureView.setSurfaceTextureListener(this);   //添加至布局   fragment.addView(textureView,new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT, Gravity.CENTER));    /**     * TextureView准备好了回调     * @param surface 内部画布渲染surface     * @param width TextureView布局宽     * @param height TextureView布局高     */    @Override    public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {        Logger.d(TAG,"onSurfaceTextureAvailable-->width:"+width+",height:"+height);        //这里对画面改变、转场播放做了处理，声明一个mSurfaceTexture ，在TextureView发生变化时更新        if (mSurfaceTexture == null) {            mSurfaceTexture = surface;            //prepare();        } else {            mTextureView.setSurfaceTexture(mSurfaceTexture);        }    }    /**     * TextureView宽高发生变化时回调     * @param surface 内部surface     * @param width 新的TextureView布局宽     * @param height 新的TextureView布局高     */    @Override    public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {        Logger.d(TAG,"onSurfaceTextureSizeChanged-->width:"+width+",height:"+height);    }    /**     * TextureView销毁时回调     * @param surface 内部surface     * @return Most applications should return true.     */    @Override    public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {        Logger.d(TAG,"onSurfaceTextureDestroyed");        return null==mSurfaceTexture;    }    /**     * TextureView刷新时回调     * @param surface 内部surface     */    @Override    public void onSurfaceTextureUpdated(SurfaceTexture surface) {    }

1.重要的状态

idle：空闲状态。当mediaPlayer没有prepareAsync之前，就是处于idle状态。prepared：准备好状态。想要让mediaPlayer开始播放，不能直接start，必须要先prepareSync。这期间mediaPlayer会一直在准备preparing，直到进入prepared状态。started：当mediaPlayer准备好，就可以调用mediaPlayer的start方法进入started状态。paused：当调用pause方法，进入paused状态。completed：播放完成，进入completed状态。error：播放错误。

2.重要的方法

prepareAsync：要想使用mediaPlayer，必须先调用prepareAsync。这是第一步。start：开始pause：暂停reset：播放完成后，如想重新开始，调用该方法。

3.重要的回调

onSurfaceTextureAvailable：开始关联mediaPlayeronPrepared：此处开始调用mediaPlayer.start()onInfo：播放开始后，视频到底状态如何，就是在onInfo中处理

 @Override    public boolean onInfo(MediaPlayer mp, int what, int extra) {        if (what == MediaPlayer.MEDIA_INFO_VIDEO_RENDERING_START) {            // 播放器渲染第一帧            mCurrentState = STATE_PLAYING;            mController.onPlayStateChanged(mCurrentState);        } else if (what == MediaPlayer.MEDIA_INFO_BUFFERING_START) {            // MediaPlayer暂时不播放，以缓冲更多的数据            if (mCurrentState == STATE_PAUSED || mCurrentState == STATE_BUFFERING_PAUSED) {                mCurrentState = STATE_BUFFERING_PAUSED;            } else {                mCurrentState = STATE_BUFFERING_PLAYING;            }            mController.onPlayStateChanged(mCurrentState);        } else if (what == MediaPlayer.MEDIA_INFO_BUFFERING_END) {            // 填充缓冲区后，MediaPlayer恢复播放/暂停            if (mCurrentState == STATE_BUFFERING_PLAYING) {                mCurrentState = STATE_PLAYING;                mController.onPlayStateChanged(mCurrentState);            }            if (mCurrentState == STATE_BUFFERING_PAUSED) {                mCurrentState = STATE_PAUSED;                mController.onPlayStateChanged(mCurrentState);            }        } else {            LogUtil.d("onInfo ——> what：" + what);        }        return true;    }

4.MediaPlayer初始化和准备播放

 mMediaPlayer = new MediaPlayer();    mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);    //设置准备播放监听器，在onPrepared回调中开始播放    mMediaPlayer.setOnPreparedListener(this);    //...此处省去一系列监听设置    //异步准备    mMediaPlayer.prepareAsync();    /**     * 播放器准备好了     * @param mp 解码器     */    @Override    public void onPrepared(MediaPlayer mp) {        Logger.d(TAG,"onPrepared");        if(null!=mSurfaceTexture){            if(null!=mSurface){                mSurface.release();                mSurface=null;            }            mSurface =new Surface(mSurfaceTexture);            mp.setSurface(mSurface);        }        //开始播放        mp.start();    }

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4、封装视频播放器4.1 封装播放器

视频播放控件应该包含两层：顶层是播放器的控制器mController，底层是播放视频内容的TextureView。这里将这两层封装在一个容器FrameLayout中；

    public VideoPlayer(@NonNull Context context, @Nullable AttributeSet attrs) {        super(context, attrs);        mContext = context;        if (mNetworkChangeReceiver == null) {            mNetworkChangeReceiver = new NetworkChangeReceiver(this);        }        allow4GFlag = false;        init();    }    private void init() {        mContainer = new FrameLayout(mContext);        mContainer.setBackgroundColor(Color.BLACK);        LayoutParams params = new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);        this.addView(mContainer, params);    }

addTextureView

private void addTextureView() {        mContainer.removeView(mTextureView);        LayoutParams params = new LayoutParams(                ViewGroup.LayoutParams.MATCH_PARENT,                ViewGroup.LayoutParams.MATCH_PARENT,                Gravity.CENTER);        mContainer.addView(mTextureView, 0, params);}

setController

public void setController(IVideoController controller) {        mContainer.removeView(mController);        mController = controller;        mController.reset();        mController.setVideoPlayer(this);        LayoutParams params = new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);        mContainer.addView(mController, params);    }

播放，将TextureView、MediaPlayer、Controller进行初始化。待TextureView的数据通道SurfaceTexture准备就绪后，打开播放器

private void openMediaPlayer() {        // 屏幕常亮        mContainer.setKeepScreenOn(true);        // 设置监听        mMediaPlayer.setOnPreparedListener(this);        mMediaPlayer.setOnVideoSizeChangedListener(this);        mMediaPlayer.setOnCompletionListener(this);        mMediaPlayer.setOnErrorListener(this);        mMediaPlayer.setOnInfoListener(this);        mMediaPlayer.setOnBufferingUpdateListener(this);        mCurrentNetworkState = NetworkChangeReceiver.getNetworkStatus(CtripBaseApplication.getInstance());        mNetworkChangeReceiver.registerNetworkChangeBroadcast();        // 设置dataSource        try {            mMediaPlayer.setDataSource(mUrl);            if (mSurface == null) {                mSurface = new Surface(mSurfaceTexture);            }            mMediaPlayer.setSurface(mSurface);            mMediaPlayer.prepareAsync();            mCurrentState = STATE_PREPARING;            mController.onPlayStateChanged(mCurrentState);        } catch (IOException e) {            e.printStackTrace();            LogUtil.e("打开播放器发生错误", e);        }    }    private void initMediaPlayer() {        if (mMediaPlayer == null) {            mMediaPlayer = new MediaPlayer();            mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);        }    }    private void initTextureView() {        if (mTextureView == null) {            mTextureView = new TourTextureView(mContext);            mTextureView.setSurfaceTextureListener(this);//此时回调onSurfaceTextureAvailable        }    }    @Override    public void onSurfaceTextureAvailable(SurfaceTexture surfaceTexture, int i, int i1) {        if (mSurfaceTexture == null) {            mSurfaceTexture = surfaceTexture;            openMediaPlayer();        } else {            mTextureView.setSurfaceTexture(mSurfaceTexture);        }    }

播放逻辑写完之后，具体UI展示逻辑在VideoPlayerController中。根据不同的状态VideoPlayerController展示不同UI

 public static final int STATE_ERROR = -1;               //播放错误    public static final int STATE_IDLE = 0;                 //播放未开始    public static final int STATE_PREPARING = 1;            //播放准备中    public static final int STATE_PREPARED = 2;             //播放准备就绪    public static final int STATE_PLAYING = 3;              //正在播放    public static final int STATE_PAUSED = 4;               //暂停播放    public static final int STATE_BUFFERING_PLAYING = 5;    //正在缓冲    public static final int STATE_BUFFERING_PAUSED = 6;     //正在缓冲 播放器    public static final int STATE_COMPLETED = 7;            //播放完成    public static final int STATE_NOTE_4G = 8;              //提示4G    public static final int STATE_NOTE_DISCONNECT = 9;      //提示断网    public static final int MODE_NORMAL = 10;               //普通模式    public static final int MODE_FULL_SCREEN = 11;          //全屏模式    public static final int MODE_TINY_WINDOW = 13;          //小窗口模式

实现全屏：将mContainer移除，并添加到android.R.content中，并设置成横屏

 @Override    public void enterFullScreen() {        if (mCurrentMode == MODE_FULL_SCREEN) return;        // 隐藏ActionBar、状态栏，并横屏        TourVideoUtil.hideActionBar(mContext);        TourVideoUtil.scanForActivity(mContext)                .setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);        new Handler().post(new Runnable() {            @Override            public void run() {                ViewGroup contentView = (ViewGroup) TourVideoUtil.scanForActivity(mContext)                        .findViewById(android.R.id.content);                if (mCurrentMode == MODE_TINY_WINDOW) {                    contentView.removeView(mContainer);                } else {                    TourVideoPlayer.this.removeView(mContainer);                }                LayoutParams params = new LayoutParams(                        ViewGroup.LayoutParams.MATCH_PARENT,                        ViewGroup.LayoutParams.MATCH_PARENT);                contentView.addView(mContainer, params);            }        });        mCurrentMode = MODE_FULL_SCREEN;        mController.onPlayModeChanged(mCurrentMode);    }

实现小窗口：将mContainer移除，添加到android.R.content中，并设置宽高

 @Override    public void enterTinyWindow() {        if (mCurrentMode == MODE_TINY_WINDOW) return;        this.removeView(mContainer);        new Handler().post(new Runnable() {            @Override            public void run() {                ViewGroup contentView = (ViewGroup) TourVideoUtil.scanForActivity(mContext)                        .findViewById(android.R.id.content);                // 小窗口的宽度为屏幕宽度的60%，长宽比默认为16:9，右边距、下边距为8dp。                FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(                        (int) (CommonUtil.getScreenWidth(mContext) * 0.6f),                        (int) (CommonUtil.getScreenWidth(mContext) * 0.6f * 9f / 16f));                params.gravity = Gravity.TOP | Gravity.START;                params.topMargin = CommonUtil.dp2px(mContext, 48f);                contentView.addView(mContainer, params);            }        });        mCurrentMode = MODE_TINY_WINDOW;        mController.onPlayModeChanged(mCurrentMode);    }

关于视频播放器封装的知识点还有很多，今天知识简单的介绍了下封装的步骤和思路；

大家如果想自己封装可以参考网上NiceVieoPlayer；

以后会继续讲解关于视频播放器的知识点；

原文链接：Android进阶之MediaPlayer和TextureView封装视频播放器详解(完美实现全屏、小窗)