android 自定义控件系列之一 圆形图控件

1.使用背景

原型图，代码中经常用到。经常需要将头像，或者摄影图片等显示为圆形。

如果你跟美工MM合作愉快，要个圆图万事大吉，但通常这种图，都是要自己处理下的。

一方面美女妹纸，除了给你提供圆图，可能还要跟IOS交互，未必愿意出多张图。另一方面，如果一个程序猿，经常需要处理圆形图，又没有自己封装好工具类，那工作效率就拉低了。

废话不多说，直接上代码。

2. 使用效果

3.核心代码

public class RoundImageViewextendsImageView { 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(Contextcontext) { super(context); mContext = context; }   public RoundImageView(Contextcontext,AttributeSet attrs) { super(context, attrs); mContext = context; setCustomAttributes(attrs); }   public RoundImageView(Contextcontext,AttributeSet attrs,int defStyle) { super(context, attrs, defStyle); mContext = context; setCustomAttributes(attrs); }   private void setCustomAttributes(AttributeSetattrs) { 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); }   @Override protected void onDraw(Canvascanvas) { 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(); }   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(Bitmapbmp,int radius) { Bitmap scaledSrcBmp; int diameter = radius * 2;   // 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(), Bitmap.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(newPorterDuffXfermode(PorterDuff.Mode.SRC_IN)); canvas.drawBitmap(scaledSrcBmp, rect, rect, paint); bmp = null; squareBitmap = null; scaledSrcBmp = null; return output; }   /** * 边缘画圆 */ private void drawCircleBorder(Canvascanvas,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); }   }4 demo 已上传github

https://github.com/jjbheda/autRoundoImage