Android自定义圆形图片，可设置最多两个的外边框。包括从网络获取图片显示。
解决图片锯齿问题。
解决图片变形问题。
原始图片：
核心代码：
/** * 圆形ImageView，可设置最多两个宽度不同且颜色不同的圆形边框。 * * @author Alan */public class RoundImageView extends ImageView {private int mBorderThickness = 0;private Context mContext;private int defaultColor = 0xFFFFFFFF;// 如果只有其中一个有值，则只画一个圆形边框private int mBorderOutsideColor = 0;private int mBorderInsideColor = 0;// 控件默认长、宽private int defaultWidth = 0;private int defaultHeight = 0;public RoundImageView(Context context) {super(context);mContext = context;}public RoundImageView(Context context, AttributeSet attrs) {super(context, attrs);mContext = context;setCustomAttributes(attrs);}public RoundImageView(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);mContext = context;setCustomAttributes(attrs);}private void setCustomAttributes(AttributeSet attrs) {TypedArray a = mContext.obtainStyledAttributes(attrs,R.styleable.roundedimageview);mBorderThickness = a.getDimensionPixelSize(R.styleable.roundedimageview_border_thickness, 0);mBorderOutsideColor = a.getColor(R.styleable.roundedimageview_border_outside_color,defaultColor);mBorderInsideColor = a.getColor(R.styleable.roundedimageview_border_inside_color, defaultColor);}@Overrideprotected void onDraw(Canvas canvas) {Drawable drawable = getDrawable();if (drawable == null) {return;}if (getWidth() == 0 || getHeight() == 0) {return;}this.measure(0, 0);if (drawable.getClass() == NinePatchDrawable.class)return;Bitmap b = ((BitmapDrawable) drawable).getBitmap();Bitmap bitmap = b.copy(Bitmap.Config.ARGB_8888, true);if (defaultWidth == 0) {defaultWidth = getWidth();}if (defaultHeight == 0) {defaultHeight = getHeight();}// 保证重新读取图片后不会因为图片大小而改变控件宽、高的大小（针对宽、高为wrap_content布局的imageview，但会导致margin无效）// if (defaultWidth != 0 && defaultHeight != 0) {// LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(// defaultWidth, defaultHeight);// setLayoutParams(params);// }int radius = 0;if (mBorderInsideColor != defaultColor&& mBorderOutsideColor != defaultColor) {// 定义画两个边框，分别为外圆边框和内圆边框radius = (defaultWidth < defaultHeight ? defaultWidth: defaultHeight) / 2 – 2 * mBorderThickness;// 画内圆drawCircleBorder(canvas, radius + mBorderThickness / 2,mBorderInsideColor);// 画外圆drawCircleBorder(canvas, radius + mBorderThickness+ mBorderThickness / 2, mBorderOutsideColor);} else if (mBorderInsideColor != defaultColor&& mBorderOutsideColor == defaultColor) {// 定义画一个边框radius = (defaultWidth < defaultHeight ? defaultWidth: defaultHeight) / 2 – mBorderThickness;drawCircleBorder(canvas, radius + mBorderThickness / 2,mBorderInsideColor);} else if (mBorderInsideColor == defaultColor&& mBorderOutsideColor != defaultColor) {// 定义画一个边框radius = (defaultWidth < defaultHeight ? defaultWidth: defaultHeight) / 2 – mBorderThickness;drawCircleBorder(canvas, radius + mBorderThickness / 2,mBorderOutsideColor);} else {// 没有边框radius = (defaultWidth < defaultHeight ? defaultWidth: defaultHeight) / 2;}Bitmap roundBitmap = getCroppedRoundBitmap(bitmap, radius);canvas.drawBitmap(roundBitmap, defaultWidth / 2 – radius, defaultHeight/ 2 – radius, null);}/** * 获取裁剪后的圆形图片 * * @param radius *半径 */public Bitmap getCroppedRoundBitmap(Bitmap bmp, int radius) {Bitmap scaledSrcBmp;int diameter = radius * 2;// 为了防止宽高不相等，，造成圆形图片变形，因此截取长方形中处于中间位置最大的正方形图片int bmpWidth = bmp.getWidth();int bmpHeight = bmp.getHeight();int squareWidth = 0, squareHeight = 0;int x = 0, y = 0;Bitmap squareBitmap;if (bmpHeight > bmpWidth) {// 高大于宽squareWidth = squareHeight = bmpWidth;x = 0;y = (bmpHeight – bmpWidth) / 2;// 截取正方形图片squareBitmap = Bitmap.createBitmap(bmp, x, y, squareWidth,squareHeight);} else if (bmpHeight < bmpWidth) {// 宽大于高squareWidth = squareHeight = bmpHeight;x = (bmpWidth – bmpHeight) / 2;y = 0;squareBitmap = Bitmap.createBitmap(bmp, x, y, squareWidth,squareHeight);} else {squareBitmap = bmp;}if (squareBitmap.getWidth() != diameter|| squareBitmap.getHeight() != diameter) {scaledSrcBmp = Bitmap.createScaledBitmap(squareBitmap, diameter,diameter, true);} else {scaledSrcBmp = squareBitmap;}Bitmap output = Bitmap.createBitmap(scaledSrcBmp.getWidth(),scaledSrcBmp.getHeight(), Config.ARGB_8888);Canvas canvas = new Canvas(output);Paint paint = new Paint();Rect rect = new Rect(0, 0, scaledSrcBmp.getWidth(),scaledSrcBmp.getHeight());paint.setAntiAlias(true);paint.setFilterBitmap(true);paint.setDither(true);canvas.drawARGB(0, 0, 0, 0);canvas.drawCircle(scaledSrcBmp.getWidth() / 2,scaledSrcBmp.getHeight() / 2, scaledSrcBmp.getWidth() / 2,paint);paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));canvas.drawBitmap(scaledSrcBmp, rect, rect, paint);// bitmap回收(recycle导致在布局文件XML看不到效果)// bmp.recycle();// squareBitmap.recycle();// scaledSrcBmp.recycle();bmp = null;squareBitmap = null;scaledSrcBmp = null;return output;}/** * 边缘画圆 */private void drawCircleBorder(Canvas canvas, int radius, int color) {Paint paint = new Paint();/* 去锯齿 */paint.setAntiAlias(true);paint.setFilterBitmap(true);paint.setDither(true);paint.setColor(color);/* 设置paint的 style 为STROKE：空心 */paint.setStyle(Paint.Style.STROKE);/* 设置paint的外框宽度 */paint.setStrokeWidth(mBorderThickness);canvas.drawCircle(defaultWidth / 2, defaultHeight / 2, radius, paint);}}布局文件：
看着它洗涤一缕缕阳光，看着它映衬一片片星辉，
