利用SurfaceView实现帧动画效果
在开发Android做动画效果的时候，有时候UI给开发一组动画实现的帧图片，如果说图片较少（十几张）、分辨率较低（几K，十几K），用帧动画实现应该没什么问题，但是如果有几十上百张、或者几百K或者上M的图片，这个时候用帧动画来实现其实就很有问题了，内存吃紧，会卡顿，OOM等问题随之而来。
当然如果可以沟通UI改设计是最好的，但是如果非得这样做不可呢？本人就遇到过这样的需求，而且还有好几种不同的图片根据状态连续来回的切换动画，这个时候还要考虑切换的时候不卡顿的问题，之前写过一篇博客利用Handler来一帧帧的去绘制，目前没有发现什么问题，也很流畅，但是不断的发送Handler消息还是有一定弊端的，所以这里带来更优的选择，用SurfaceView来加载图片，因为这个控件是另开子线程利用双缓存加载资源再直接绘制Surface上，不影响主线程，还避过了大部分java层的耗时操作。因此此选择更优。
具体代码实现如下：
注意一下，如果是png带透明背景的图片，需要surfaceView透明背景的实现：
//设置透明背景
//setZOrderOnTop(true) 必须在setFormat方法之前，不然png的透明效果不生效
setZOrderOnTop(true);
mSurfaceHolder.setFormat(PixelFormat.TRANSLUCENT);
public class SurfaceViewAnimation extends SurfaceView implements SurfaceHolder.Callback, Runnable {
private String TAG = "SurfaceViewAnimation";
private SurfaceHolder mSurfaceHolder;
private boolean mIsThreadRunning = true; // 线程运行开关
public static boolean mIsDestroy = false;// 是否已经销毁
private int[] mBitmapResourceIds;// 用于播放动画的图片资源id数组
private int totalCount;//资源总数 用来判断动画循环
private Canvas mCanvas; // 画图片
private Bitmap mBitmap;// 显示的图片的bitmap
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 boolean mIsRepeat = false;
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() {
mSurfaceHolder = this.getHolder();
mSurfaceHolder.addCallback(this);
mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_HARDWARE);
//设置透明背景
//setZOrderOnTop(true) 必须在setFormat方法之前，不然png的透明效果不生效
setZOrderOnTop(true);
mSurfaceHolder.setFormat(PixelFormat.TRANSLUCENT);
mBitmapResourceIds = new int[1];
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// 根据实际需要是利用start()函数外部开启调用开启动画线程，还是显示控件就开启动画
mIsThreadRunning = ture;
new Thread(this).start();
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
destroy();
}
/**
* 制图方法
*/
private void drawView() {
// 无资源文件退出
if (mBitmapResourceIds == null && mBitmapResourcePaths == null) {
Log.e("frameview", "the bitmapsrcIDs is null");
mIsThreadRunning = false;
return;
}
Log.d(TAG, "drawView: mCurrentIndext=" + mCurrentIndext);
Log.d(TAG, "drawView: Thread id = " + Thread.currentThread().getId());
//防止是获取不到Canvas
SurfaceHolder surfaceHolder = mSurfaceHolder;
// 锁定画布
synchronized (surfaceHolder) {
if (surfaceHolder != null) {
mCanvas = surfaceHolder.lockCanvas();
Log.d(TAG, "drawView: mCanvas= " + mCanvas);
if (mCanvas == null) {
return;
}
}
try {
if (surfaceHolder != null && mCanvas != null) {
synchronized (mBitmapResourceIds) {
if (mBitmapResourceIds != null && mBitmapResourceIds.length > 0) {
mBitmap = BitmapUtil.decodeSampledBitmapFromResource(getResources(), mBitmapResourceIds[mCurrentIndext], getWidth(), getHeight());
} else if (mBitmapResourcePaths != null && mBitmapResourcePaths.size() > 0) {
mBitmap = BitmapFactory.decodeFile(mBitmapResourcePaths.get(mCurrentIndext));
}
}
mBitmap.setHasAlpha(true);
if (mBitmap == null) {
return;
}
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);
// 播放到最后一张图片
if (mCurrentIndext == totalCount - 1) {
//TODO 设置重复播放
//播放到最后一张，当前index置零
mCurrentIndext = 0;
}
}
} catch (Exception e) {
Log.d(TAG, "drawView: e =" + e.toString());
e.printStackTrace();
} finally {
mCurrentIndext++;
if (mCurrentIndext >= totalCount) {
mCurrentIndext = 0;
}
if (mCanvas != null) {
// 将画布解锁并显示在屏幕上
if (getHolder() != null) {
surfaceHolder.unlockCanvasAndPost(mCanvas);
}
}
if (mBitmap != null) {
// 收回图片
mBitmap.recycle();
}
}
}
}
@Override
public void run() {
if (mOnFrameFinishedListener != null) {
mOnFrameFinishedListener.onStart();
}
Log.d(TAG, "run: mIsThreadRunning=" + mIsThreadRunning);
// 每隔mGapTimems刷新屏幕
while (mIsThreadRunning) {
drawView();
try {
Thread.sleep(mGapTime);
} catch (Exception e) {
e.printStackTrace();
}
}
if (mOnFrameFinishedListener != null) {
mOnFrameFinishedListener.onStop();
}
}
/**
* 开始动画
*/
public void start() {
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;
thread.interrupt();
thread = null;
if (mBitmap != null) {
mBitmap.recycle();
mBitmap = null;
}
if (mSurfaceHolder != null) {
mSurfaceHolder.addCallback(null);
}
if (mOnFrameFinishedListener != null) {
mOnFrameFinishedListener = null;
}
}
/**
* 设置动画播放素材的id
*
* @param bitmapResourceIds 图片资源id
*/
public void setBitmapResoursID(int[] bitmapResourceIds) {
// 防止主线程和子线程同时操作mBitmapResourceIds资源造成死锁
synchronized (mBitmapResourceIds) {
this.mBitmapResourceIds = bitmapResourceIds;
totalCount = bitmapResourceIds.length;
}
}
/**
* 设置动画播放素材的路径
*
* @param bitmapResourcePaths
*/
public void setmBitmapResourcePath(ArrayList bitmapResourcePaths) {
this.mBitmapResourcePaths = bitmapResourcePaths;
totalCount = bitmapResourcePaths.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() {
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 onStart();
/**
* 动画结束
*/
void onStop();
}
}