Android自定义View旋转圆形图片

public class MusicPlayerView extends View { private static final long ROTATE_DELAY = 5;//旋转动作时间 private int mRotateDegrees;//旋转的角度 private Handler mRotate; private int mWidth; private int mHeight; private float mCenterX; private float mCenterY; private RectF rectF; private Bitmap mBitmapCover; private float mCoverScale; private BitmapShader mShader; private Paint paint; private boolean isRotating; private final Runnable mRunnableRotate = new Runnable() {  @Override  public void run() {   if (isRotating) {    updateCoverRotate();    mRotate.postDelayed(mRunnableRotate, ROTATE_DELAY);   }  } }; /**  * 更新封面角度,重新绘制图片  */ private void updateCoverRotate() {  mRotateDegrees += 1;  mRotateDegrees = mRotateDegrees % 360;  postInvalidate(); } /**  * 判读是否在旋转  * @return  */ public boolean isRotating() {  return isRotating; } /**  * 开始旋转图片  */ public void start(){  isRotating=true;  mRotate.removeCallbacksAndMessages(null);  mRotate.postDelayed(mRunnableRotate,ROTATE_DELAY);  postInvalidate(); } /**  * 停止图片旋转  */ public void stop(){  isRotating = false;  postInvalidate(); } /**  * 通过本地图片设置封面图  */ public void setCoverDrawable(int coverDrawable) {  Drawable drawable = getContext().getResources().getDrawable(coverDrawable);  mBitmapCover = drawableToBitmap(drawable);  createShader();  postInvalidate(); } /**  * 网络图片加载使用Picasso图片加载工具  *  * @param imageUrl  */ public void setCoverURL(String imageUrl) {  Picasso.with(getContext()).load(imageUrl).into(target); } public MusicPlayerView(Context context) {  super(context);  init(context, null); } public MusicPlayerView(Context context, AttributeSet attrs) {  super(context, attrs);  init(context, attrs); } public MusicPlayerView(Context context, AttributeSet attrs, int defStyleAttr) {  super(context, attrs, defStyleAttr);  init(context, attrs); } /**  * 初始化View资源  *  * @param context  * @param attrs  */ private void init(Context context, AttributeSet attrs) {  setWillNotDraw(false);  TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.play_view);  Drawable mDrawableCover = a.getDrawable(R.styleable.play_view_cover);  if (mDrawableCover != null) {   mBitmapCover = drawableToBitmap(mDrawableCover);  }  a.recycle();  mRotateDegrees = 0;  //通过handler更新图片角度  mRotate = new Handler();  rectF = new RectF(); } /**  * 测量宽高,设置中心点中心点位置,创建阴影  *  * @param widthMeasureSpec  * @param heightMeasureSpec  */ @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {  mWidth = MeasureSpec.getSize(widthMeasureSpec);  mHeight = MeasureSpec.getSize(heightMeasureSpec);  int minSide = Math.min(mWidth, mHeight); //取宽高最小值设置图片宽高  mWidth = minSide;  mHeight = minSide;  setMeasuredDimension(mWidth, mHeight);  //重新设置宽高  //中心点位置  mCenterX = mWidth / 2f;  mCenterY = mHeight / 2f;  //设置图片显示位置  rectF.set(20.0f, 20.0f, mWidth - 20.0f, mHeight - 20.0f);  createShader();  super.onMeasure(widthMeasureSpec, heightMeasureSpec); } @Override protected void onDraw(Canvas canvas) {  super.onDraw(canvas);  if (mShader == null) {   return;  }  //画封面图片 判读图片的中心距离xy,算出边角大小,然后画圆  float radius = mCenterX <= mCenterY ? mCenterX - 75.0f : mCenterY - 75.0f;  canvas.rotate(mRotateDegrees, mCenterX, mCenterY);  canvas.drawCircle(mCenterX, mCenterY, radius, paint); } @Override public boolean onTouchEvent(MotionEvent event) {  switch (event.getAction()) {   case MotionEvent.ACTION_DOWN:    break;  }  return super.onTouchEvent(event); } private Target target = new Target() {  @Override  public void onBitmapLoaded(Bitmap bitmap, Picasso.LoadedFrom from) {   mBitmapCover = bitmap;   createShader();   postInvalidate();  }  @Override  public void onBitmapFailed(Drawable errorDrawable) {  }  @Override  public void onPrepareLoad(Drawable placeHolderDrawable) {  } }; private int mCoverColor = Color.YELLOW; private void createShader() {  if (mWidth == 0) {   return;  }  if (mBitmapCover == null) { //如果封面为为创建默认颜色   mBitmapCover = Bitmap.createBitmap(mWidth, mHeight, Bitmap.Config.ARGB_8888);   mBitmapCover.eraseColor(mCoverColor);  }  mCoverScale = ((float) mWidth) / (float) mBitmapCover.getWidth();  //创建缩放后的bitmap  mBitmapCover = Bitmap.createScaledBitmap(mBitmapCover,    (int) (mBitmapCover.getWidth() * mCoverScale), (int) (mBitmapCover.getHeight() * mCoverScale), true);  mShader = new BitmapShader(mBitmapCover, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);  paint = new Paint();  paint.setAntiAlias(true);  paint.setShader(mShader); } /**  * 将drawable转换为位图 为BitmapShader准备  *  * @param drawable  * @return  */ private Bitmap drawableToBitmap(Drawable drawable) {  if (drawable instanceof BitmapDrawable) {   return ((BitmapDrawable) drawable).getBitmap();  }  int width = drawable.getIntrinsicWidth();  width = width > 0 ? width : 1;  int height = drawable.getIntrinsicHeight();  height = height > 0 ? height : 1;  Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);  Canvas canvas = new Canvas(bitmap);  drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());  drawable.draw(canvas);  return bitmap; }}

<?xml version="1.0" encoding="utf-8"?><resources> <declare-styleable name="play_view">  <attr name="cover" format="integer"/> </declare-styleable></resources>