<declare-styleable name="RoundImageView"><attr name="circle" format="boolean" /><attr name="radius" format="dimension" /></declare-styleable>

public class RoundImageView  extends ImageView {private Paint paint;private Paint paintBorder;private Bitmap mSrcBitmap;/*** 圆角的弧度*/private float mRadius;private boolean mIsCircle;public RoundImageView(final Context context) {this(context, null);}public RoundImageView(Context context, AttributeSet attrs) {super(context, attrs);TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.RoundImageView);mRadius = ta.getDimension(R.styleable.RoundImageView_radius, 0);mIsCircle = ta.getBoolean(R.styleable.RoundImageView_circle, false);int srcResource = attrs.getAttributeResourceValue("http://schemas.android.com/apk/res/android", "src", 0);if (srcResource != 0)mSrcBitmap = BitmapFactory.decodeResource(getResources(),srcResource);ta.recycle();paint = new Paint();paint.setAntiAlias(true);paintBorder = new Paint();paintBorder.setAntiAlias(true);}@Overridepublic void onDraw(Canvas canvas) {int width = canvas.getWidth() - getPaddingLeft() - getPaddingRight();int height = canvas.getHeight() - getPaddingTop() - getPaddingBottom();Bitmap image = drawableToBitmap(getDrawable());if (mIsCircle) {Bitmap reSizeImage = reSizeImageC(image, width, height);canvas.drawBitmap(createCircleImage(reSizeImage, width, height),getPaddingLeft(), getPaddingTop(), null);} else {Bitmap reSizeImage = reSizeImage(image, width, height);canvas.drawBitmap(createRoundImage(reSizeImage, width, height),getPaddingLeft(), getPaddingTop(), null);}}/*** 画圆角** @param source* @param width* @param height* @return*/private Bitmap createRoundImage(Bitmap source, int width, int height) {Paint paint = new Paint();paint.setAntiAlias(true);Bitmap target = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);Canvas canvas = new Canvas(target);RectF rect = new RectF(0, 0, width, height);canvas.drawRoundRect(rect, mRadius, mRadius, paint);// 核心代码取两个图片的交集部分paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));canvas.drawBitmap(source, 0, 0, paint);return target;}/*** 画圆** @param source* @param width* @param height* @return*/private Bitmap createCircleImage(Bitmap source, int width, int height) {Paint paint = new Paint();paint.setAntiAlias(true);Bitmap target = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);Canvas canvas = new Canvas(target);canvas.drawCircle(width / 2, height / 2, Math.min(width, height) / 2,paint);// 核心代码取两个图片的交集部分paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));canvas.drawBitmap(source, (width - source.getWidth()) / 2,(height - source.getHeight()) / 2, paint);return target;}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {int width = MeasureSpec.getSize(widthMeasureSpec);int height = MeasureSpec.getSize(heightMeasureSpec);setMeasuredDimension(width, height);}/*** drawable转bitmap** @param drawable* @return*/private Bitmap drawableToBitmap(Drawable drawable) {if (drawable == null) {if (mSrcBitmap != null) {return mSrcBitmap;} else {return null;}} else if (drawable instanceof BitmapDrawable) {return ((BitmapDrawable) drawable).getBitmap();}Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(),drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);Canvas canvas = new Canvas(bitmap);drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());drawable.draw(canvas);return bitmap;}/*** 重设Bitmap的宽高** @param bitmap* @param newWidth* @param newHeight* @return*/private Bitmap reSizeImage(Bitmap bitmap, int newWidth, int newHeight) {int width = bitmap.getWidth();int height = bitmap.getHeight();// 计算出缩放比float scaleWidth = ((float) newWidth) / width;float scaleHeight = ((float) newHeight) / height;// 矩阵缩放bitmapMatrix matrix = new Matrix();matrix.postScale(scaleWidth, scaleHeight);return Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);}/*** 重设Bitmap的宽高** @param bitmap* @param newWidth* @param newHeight* @return*/private Bitmap reSizeImageC(Bitmap bitmap, int newWidth, int newHeight) {int width = bitmap.getWidth();int height = bitmap.getHeight();int x = (newWidth - width) / 2;int y = (newHeight - height) / 2;if (x > 0 && y > 0) {return Bitmap.createBitmap(bitmap, 0, 0, width, height, null, true);}float scale = 1;if (width > height) {// 按照宽度进行等比缩放scale = ((float) newWidth) / width;} else {// 按照高度进行等比缩放// 计算出缩放比scale = ((float) newHeight) / height;}Matrix matrix = new Matrix();matrix.postScale(scale, scale);return Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);}}

 <RoundImageViewandroid:layout_width="40dp"android:layout_height="40dp"android:scaleType="centerCrop"android:id="@+id/headImg"android:src="@mipmap/menudefault"app:radius="20dp"/>