QQ音乐中圆形旋转碟子

思路分析：

1、在onMeasure中测量整个View的宽和高后，设置宽高

2、获取我们res的图片资源后，在ondraw方法中进行绘制圆形图片

3、通过Handler发送Runnable来启动旋转线程（如果只想做圆形头像的话，这步可以去掉）

4、在布局中使用我们的View

效果图：

贴出我们的变量信息：

//view的宽和高 int mHeight = 0; int mWidth = 0; //圆形图片 Bitmap bitmap = null; //圆形图片的真实半径 int radius = 0; //旋转动画的矩形 Matrix matrix = new Matrix(); //旋转动画的角度 int degrees = 0;

步骤一：测量整个View的宽和高后，设置宽高

@Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); //测量整个View的宽和高 mWidth = measuredWidth(widthMeasureSpec); mHeight= measuredHeight(heightMeasureSpec); setMeasuredDimension(mWidth, mHeight); } private int measuredWidth(int widthMeasureSpec) { int Mode = MeasureSpec.getMode(widthMeasureSpec); int Size = MeasureSpec.getSize(widthMeasureSpec); if (Mode == MeasureSpec.EXACTLY) { mWidth = Size; } else { //由图片决定宽度 int value = getPaddingLeft() + getPaddingRight() + bitmap.getWidth(); if (Mode == MeasureSpec.AT_MOST) { //由图片和Padding决定宽度，但是不能超过View的宽 mWidth = Math.min(value, Size); } } return mWidth; } private int measuredHeight(int heightMeasureSpec) { int Mode = MeasureSpec.getMode(heightMeasureSpec); int Size = MeasureSpec.getSize(heightMeasureSpec); if (Mode == MeasureSpec.EXACTLY) { mHeight = Size; } else { //由图片决定高度 int value = getPaddingTop() + getPaddingBottom() + bitmap.getHeight(); if (Mode == MeasureSpec.AT_MOST) { //由图片和Padding决定高度，但是不能超过View的高 mHeight = Math.min(value, Size); } } return mHeight; }

步骤二：获取我们res的图片资源后，在ondraw方法中进行绘制圆形图片

//获取res的图片资源 bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.icon); @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); canvas.concat(matrix); //真实的半径必须是View的宽高最小值 radius = Math.min(mWidth, mHeight); //如果图片本身宽高太大，进行相应的缩放 bitmap = Bitmap.createScaledBitmap(bitmap, radius, radius, false); //画圆形图片 canvas.drawBitmap(createCircleImage(bitmap, radius), 0, 0, null); matrix.reset(); } private Bitmap createCircleImage(Bitmap source, int radius) { Paint paint = new Paint(); paint.setAntiAlias(true); Bitmap target = Bitmap.createBitmap(radius, radius, Bitmap.Config.ARGB_8888); //产生一个同样大小的画布 Canvas canvas = new Canvas(target); //首先绘制圆形 canvas.drawCircle(radius / 2, radius / 2, radius / 2, paint); //使用SRC_IN模式显示后画图的交集处 paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN)); //绘制图片，从（0，0）画 canvas.drawBitmap(source, 0, 0, paint); return target; }

步骤三：通过Handler发送Runnable来启动旋转线程

//开始旋转 mHandler.post(runnable); [java] view plain copy 在CODE上查看代码片派生到我的代码片 //-----------旋转动画----------- Handler mHandler = new Handler(); Runnable runnable = new Runnable() { @Override public void run() { matrix.postRotate(degrees++, radius / 2, radius / 2); //重绘 invalidate(); mHandler.postDelayed(runnable, 50); } };

步骤四：在布局中使用我们的View

<com.handsome.cycle.MyCycleView android:layout_width="wrap_content" android:layout_height="wrap_content" />

下面是整个类的源码

public class MyCycleView extends View { //view的宽和高 int mHeight = 0; int mWidth = 0; //圆形图片 Bitmap bitmap = null; //圆形图片的真实半径 int radius = 0; //旋转动画的矩形 Matrix matrix = new Matrix(); //旋转动画的角度 int degrees = 0; //-----------旋转动画----------- Handler mHandler = new Handler(); Runnable runnable = new Runnable() { @Override public void run() { matrix.postRotate(degrees++, radius / 2, radius / 2); //重绘 invalidate(); mHandler.postDelayed(runnable, 50); } }; public MyCycleView(Context context) { super(context); initView(); } public MyCycleView(Context context, AttributeSet attrs) { super(context, attrs); initView(); } public MyCycleView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); initView(); } public void initView() { //获取res的图片资源 bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.icon); //开始旋转 mHandler.post(runnable); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); //测量整个View的宽和高 mWidth = measuredWidth(widthMeasureSpec); mHeight = measuredHeight(heightMeasureSpec); setMeasuredDimension(mWidth, mHeight); } private int measuredWidth(int widthMeasureSpec) { int Mode = MeasureSpec.getMode(widthMeasureSpec); int Size = MeasureSpec.getSize(widthMeasureSpec); if (Mode == MeasureSpec.EXACTLY) { mWidth = Size; } else { //由图片决定宽度 int value = getPaddingLeft() + getPaddingRight() + bitmap.getWidth(); if (Mode == MeasureSpec.AT_MOST) { //由图片和Padding决定宽度，但是不能超过View的宽 mWidth = Math.min(value, Size); } } return mWidth; } private int measuredHeight(int heightMeasureSpec) { int Mode = MeasureSpec.getMode(heightMeasureSpec); int Size = MeasureSpec.getSize(heightMeasureSpec); if (Mode == MeasureSpec.EXACTLY) { mHeight = Size; } else { //由图片决定高度 int value = getPaddingTop() + getPaddingBottom() + bitmap.getHeight(); if (Mode == MeasureSpec.AT_MOST) { //由图片和Padding决定高度，但是不能超过View的高 mHeight = Math.min(value, Size); } } return mHeight; } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); canvas.concat(matrix); //真实的半径必须是View的宽高最小值 radius = Math.min(mWidth, mHeight); //如果图片本身宽高太大，进行相应的缩放 bitmap = Bitmap.createScaledBitmap(bitmap, radius, radius, false); //画圆形图片 canvas.drawBitmap(createCircleImage(bitmap, radius), 0, 0, null); matrix.reset(); } private Bitmap createCircleImage(Bitmap source, int radius) { Paint paint = new Paint(); paint.setAntiAlias(true); Bitmap target = Bitmap.createBitmap(radius, radius, Bitmap.Config.ARGB_8888); //产生一个同样大小的画布 Canvas canvas = new Canvas(target); //首先绘制圆形 canvas.drawCircle(radius / 2, radius / 2, radius / 2, paint); //使用SRC_IN模式显示后画图的交集处 paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN)); //绘制图片，从（0，0）画 canvas.drawBitmap(source, 0, 0, paint); return target; } }

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