帧动画如何实现，网上一搜一堆，不再赘述。

这里记录下实现的一个需求。

播放卫星云图，所谓云图，就是很多张图片连起来。所以播放的效果就是帧动画的效果。

那么首先想到的实现方式就是帧动画-----AnimationDrawable。

也确实是这样，用帧动画实现此效果很简单，就是常规的实现方式。

主要实现如下：

private fun loadFrameImages() {for (pos in mImageList.indices) {loadImage(mImageList[pos], pos)}}private fun loadImage(url: String?, pos: Int) {runSafety {url?.let {val simpleTarget = object: SimpleTarget<Drawable>() {override fun onResourceReady(resource: Drawable, transition: Transition<in Drawable>?) {mHashMap[pos] = resourceaddFrameToPlay()}}Glide.with(this).load(it).into(simpleTarget)}}}private fun addFrameToPlay() {if (mHashMap.size > 0 && mHashMap.size == mImageList.size) {tvFrameEnd?.text = "" + mHashMap.sizefor (index in mImageList.indices) {mAnimationDrawable?.addFrame(mHashMap[index], 500)}ivCloud?.setImageDrawable(mAnimationDrawable)isPlaying = truemAnimationDrawable?.startAuto()ivPlay?.setBackgroundResource(R.mipmap.icon_cloud_pause)tvFrameStart?.text = "" + getCurrentIndex()}}

AnimationDrawable其实就是个Drawable，本身并没有监听。而我们需要监听动画播放开始，结束。所以自定义实现。

class CustomAnimationDrawable: AnimationDrawable() {private var mHandler = Handler()private val mAnimationRunnable = Runnable { dealWithCallback() }private var mMaxDuration: Long = 0Lprivate var mOnFrameAnimationListener: OnFrameAnimationListener? = nullprivate fun dealWithCallback() {//获取最后一帧，和当前帧做比较，如果相等，就结束动画，调用动画结束回调Trace.e("dealWithCallback", "当前帧是: $current")if (getFrame(numberOfFrames - 1) != current) {mOnFrameAnimationListener?.onFramePlaying(current)initHandlerFrame(current) //如果不是最后一帧，重新启动handler} else {onFinish() //如果是最后一帧，触发结束回调}}private fun initHandler(index: Int) {Trace.e("initHandler", "重新播放: $index")val delayMills = if (mMaxDuration == 0L) getMaxDurationIndex(index) else mMaxDurationmHandler?.postDelayed(mAnimationRunnable, delayMills)}private fun initHandlerFrame(frame: Drawable?) {val delayMills = if (mMaxDuration == 0L) getMaxDuration(frame) else mMaxDurationmHandler?.postDelayed(mAnimationRunnable, delayMills)}private fun onFinish() {mOnFrameAnimationListener?.onFrameEnd()mHandler.removeCallbacks(mAnimationRunnable)}/*** 说明：重写开始方法监听动画* 作者：* 添加时间：2020/7/9 16:28* 修改人：* 修改时间：2020/7/9 16:28*/override fun start() {super.start()}override fun scheduleSelf(what: Runnable, `when`: Long) {super.scheduleSelf(what, `when`)}override fun stop() {super.stop()}fun startAuto() {initHandlerFrame(current)mOnFrameAnimationListener?.onFrameStart();//触发动画开始回调start()}fun startManual(currentIndex: Int) {initHandler(currentIndex)mOnFrameAnimationListener?.onFrameStart();//触发动画开始回调start()}fun stopManual(currentIndex: Int) {mHandler?.removeCallbacks(mAnimationRunnable)stop()mOnFrameAnimationListener?.onTempStop(current)}/*** 获取持续时间最长的帧的持续时间** @return 时间  如果这一帧大于1秒，则返回 1 秒，否则返回这一帧的持续时间*/private fun getMaxDuration(frame: Drawable?): Long {for (i in 0 until this.numberOfFrames) {if (mMaxDuration < getDuration(i)) {mMaxDuration = getDuration(i).toLong()}}return if (mMaxDuration > 1000) 1000 else mMaxDuration}private fun getMaxDurationIndex(index: Int): Long {for (i in 0 until index) {if (mMaxDuration < getDuration(i)) {mMaxDuration = getDuration(i).toLong()}}return if (mMaxDuration > 1000) 1000 else mMaxDuration}private fun getTotalDuration(): Long {var iDuration = 0for (i in 0 until this.numberOfFrames) {iDuration += getDuration(i)}return iDuration.toLong()}/*** 设置动画监听器** @param onFrameAnimationListener 监听器*/fun setOnFrameAnimationListener(onFrameAnimationListener: OnFrameAnimationListener?) {mOnFrameAnimationListener = onFrameAnimationListener}/*** 动画监听器*/interface OnFrameAnimationListener {/*** 动画开始*/fun onFrameStart()fun onFramePlaying(currentFrame: Drawable)fun onTempStop(currentFrame: Drawable?) //播放到某一帧，暂停/*** 动画结束*/fun onFrameEnd()}}

这样可以实现自动播放。

但是，无法实现暂停-播放效果。因为start()方法每次都是从第一帧开始播放的。

这种情况下就无法满足需求了。

那就换一种方式：

public class SurfaceViewAnimation extends TextureView implements TextureView.SurfaceTextureListener, Runnable {private String TAG = "SurfaceViewAnimation2";private boolean mIsThreadRunning = true; // 线程运行开关public boolean mIsDestroy = false;// 是否已经销毁private HashMap<Integer, Bitmap> mBitmapMaps = new HashMap<>();private int totalCount;//资源总数private Canvas mCanvas;private Bitmap mBitmap;// 显示的图片private int mCurrentIndext;// 当前动画播放的位置private int mGapTime = 50;// 每帧动画持续存在的时间private OnFrameFinishedListener mOnFrameFinishedListener;// 动画监听事件private Thread thread;Rect mSrcRect, mDestRect;public SurfaceViewAnimation(Context context) {this(context, null);initView();}public SurfaceViewAnimation(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);initView();}public SurfaceViewAnimation(Context context, AttributeSet attrs) {this(context, attrs, 0);initView();}private void initView() {try {initVariables();setOpaque(false);//设置背景透明，记住这里是[是否不透明]} catch (Exception e) {e.printStackTrace();}}@Overridepublic void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {}@Overridepublic void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {}@Overridepublic boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {try {destroy();} catch (Exception e) {e.printStackTrace();}return false;}@Overridepublic void onSurfaceTextureUpdated(SurfaceTexture surface) {}public void drawIndex(int pos) {mCurrentIndext = pos;drawView();}public void drawPreIndex(int pos) {if (pos < totalCount + 1) {mCurrentIndext = pos - 1;drawView();}}public void drawAfterIndex() {drawView();}/*** 绘制*/private void drawView() {// 无资源文件退出if (mBitmapMaps == null) {mIsThreadRunning = false;return;}if (mOnFrameFinishedListener != null) {mOnFrameFinishedListener.onFramePlaying(mCurrentIndext);}Log.e(TAG, "drawView: mCurrentIndext=" + mCurrentIndext);Log.e(TAG, "drawView: Thread id = " + Thread.currentThread().getId());//防止是获取不到Canvas// 锁定画布mCanvas = lockCanvas();if (mCanvas == null) {return;}try {if (mCanvas != null && mBitmapMaps != null) {synchronized (mBitmapMaps) {if (mBitmapMaps != null && mBitmapMaps.size() > 0 && mCurrentIndext > -1 && mCurrentIndext < mBitmapMaps.size()) {mBitmap = mBitmapMaps.get(mCurrentIndext);}}if (mBitmap == null || mBitmap.isRecycled()) {return;}if (!mBitmap.isRecycled()) {mBitmap.setHasAlpha(true);}Paint paint = new Paint();paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));mCanvas.drawPaint(paint);paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC));paint.setAntiAlias(true);paint.setStyle(Paint.Style.STROKE);mSrcRect = new Rect(0, 0, mBitmap.getWidth(), mBitmap.getHeight());mDestRect = new Rect(0, 0, getWidth(), getHeight());mCanvas.drawBitmap(mBitmap, mSrcRect, mDestRect, paint);}} catch (Exception e) {Log.d(TAG, "drawView: e =" + e.toString());e.printStackTrace();} finally {if (mCurrentIndext == totalCount) {mIsThreadRunning = false;if (thread != null) {thread.interrupt();thread = null;}if (mOnFrameFinishedListener != null) {mOnFrameFinishedListener.onFrameEnd();}} else {mCurrentIndext++;if (mCurrentIndext > totalCount) {mCurrentIndext = 0;}}if (mCanvas != null) {// 将画布解锁并显示在屏幕上unlockCanvasAndPost(mCanvas);}}}@Overridepublic void run() {if (mOnFrameFinishedListener != null) {mOnFrameFinishedListener.onFrameStart();}Log.e(TAG, "run: mIsThreadRunning=" + mIsThreadRunning);// 每隔150ms刷新屏幕while (mIsThreadRunning) {drawView();try {Thread.sleep(mGapTime);} catch (Exception e) {e.printStackTrace();}}if (mOnFrameFinishedListener != null) {mOnFrameFinishedListener.onFrameStop();}}/*** 开始动画*/public void start() {if (mCurrentIndext == totalCount) {mIsDestroy = false;}if (!mIsDestroy) {mCurrentIndext = 0;mIsThreadRunning = true;thread = new Thread(this);thread.start();} else {// 如果SurfaceHolder已经销毁抛出该异常try {throw new Exception("IllegalArgumentException:Are you sure the SurfaceHolder is not destroyed");} catch (Exception e) {e.printStackTrace();}}}/*** 防止内存泄漏*/private void destroy() {//当surfaceView销毁时, 停止线程的运行. 避免surfaceView销毁了线程还在运行而报错.mIsThreadRunning = false;try {Thread.sleep(mGapTime);} catch (InterruptedException e) {e.printStackTrace();}mIsDestroy = true;if (thread != null) {thread.interrupt();thread = null;}if (mBitmap != null && !mBitmap.isRecycled()) {mBitmap.recycle();mBitmap = null;}}void destroyListener() {if (mOnFrameFinishedListener != null) {mOnFrameFinishedListener = null;}}public void setBitmapArrays(HashMap<Integer, Bitmap> bitmapArrays) {synchronized (mBitmapMaps) {mBitmapMaps = bitmapArrays;totalCount = mBitmapMaps.size();}}/*** 设置每帧时间*/public void setGapTime(int gapTime) {this.mGapTime = gapTime;}/*** 结束动画*/public void stop() {mIsThreadRunning = false;}/*** 继续动画*/public void reStart() {try {Log.e("reStart", "当前位置: " + mCurrentIndext);mIsThreadRunning = true;thread = new Thread(this);thread.start();} catch (Exception e) {e.printStackTrace();}}public void pause() {mIsThreadRunning = false;}/*** 设置动画监听器*/public void setOnFrameFinisedListener(OnFrameFinishedListener onFrameFinishedListener) {this.mOnFrameFinishedListener = onFrameFinishedListener;}/*** 动画监听器** @author qike*/public interface OnFrameFinishedListener {/*** 动画开始*/void onFrameStart();void onFramePlaying(int framePos);/*** 动画结束*/void onFrameStop();//停止(可能未播放完)void onFrameEnd();//播放完毕}/*** 当用户点击返回按钮时，停止线程，反转内存溢出*/@Overridepublic boolean onKeyDown(int keyCode, KeyEvent event) {// 当按返回键时，将线程停止，避免surfaceView销毁了,而线程还在运行而报错if (keyCode == KeyEvent.KEYCODE_BACK) {mIsThreadRunning = false;}return super.onKeyDown(keyCode, event);}private SizeCalculator mSizeCalculator = null;@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {if (mSizeCalculator != null) {ViewSize size =mSizeCalculator.measure(widthMeasureSpec, heightMeasureSpec);setMeasuredDimension(size.width, size.height);}}class ViewSize {int width = 0;int height = 0;}class SizeCalculator {private int mVideoWidth = 0;private int mVideoHeight = 0;void setVideoSize(int width, int height) {mVideoWidth = width;mVideoHeight = height;}ViewSize measure(int widthMeasureSpec, int heightMeasureSpec) {int width = View.getDefaultSize(mVideoWidth, widthMeasureSpec);int height = View.getDefaultSize(mVideoHeight, heightMeasureSpec);if (mVideoWidth > 0 && mVideoHeight > 0) {int widthSpecMode = MeasureSpec.getMode(widthMeasureSpec);int widthSpecSize = MeasureSpec.getSize(widthMeasureSpec);int heightSpecMode = MeasureSpec.getMode(heightMeasureSpec);int heightSpecSize = MeasureSpec.getSize(heightMeasureSpec);if (widthSpecMode == MeasureSpec.EXACTLY && heightSpecMode == MeasureSpec.EXACTLY) {// the size is fixedwidth = widthSpecSize;height = heightSpecSize;// for compatibility, we adjust size based on aspect ratioif (mVideoWidth * height < width * mVideoHeight) {width = height * mVideoWidth / mVideoHeight;} else if (mVideoWidth * height > width * mVideoHeight) {height = width * mVideoHeight / mVideoWidth;}} else if (widthSpecMode == MeasureSpec.EXACTLY) {// only the width is fixed, adjust the height to match aspect ratio if possiblewidth = widthSpecSize;height = width * mVideoHeight / mVideoWidth;if (heightSpecMode == MeasureSpec.AT_MOST && height > heightSpecSize) {// couldn't match aspect ratio within the constraintsheight = heightSpecSize;}} else if (heightSpecMode == MeasureSpec.EXACTLY) {// only the height is fixed, adjust the width to match aspect ratio if possibleheight = heightSpecSize;width = height * mVideoWidth / mVideoHeight;if (widthSpecMode == MeasureSpec.AT_MOST && width > widthSpecSize) {// couldn't match aspect ratio within the constraintswidth = widthSpecSize;}} else {// neither the width nor the height are fixed, try to use actual video sizewidth = mVideoWidth;height = mVideoHeight;if (heightSpecMode == MeasureSpec.AT_MOST && height > heightSpecSize) {// too tall, decrease both width and heightheight = heightSpecSize;width = height * mVideoWidth / mVideoHeight;}if (widthSpecMode == MeasureSpec.AT_MOST && width > widthSpecSize) {// too wide, decrease both width and heightwidth = widthSpecSize;height = width * mVideoHeight / mVideoWidth;}}}ViewSize size = new ViewSize();size.width = width;size.height = height;return size;}}private void initVariables() {mSizeCalculator = new SizeCalculator();mSizeCalculator.setVideoSize(0, 0);}}

这样，可以基本实现需求。