Android应用自定义圆角图片RoundImageView，,Android开发中图片

Android应用自定义圆角图片RoundImageView，,Android开发中图片

Android开发中图片控件ImageView默认的样子是矩形，方方正正的。在我们实际的项目中，有时候这些方正的图片显得有些呆板，我们就需要其它样式的图片，比较圆形图片（Theroundedpicture），常见的就是app中用户头像等。要得到圆形图片有很多方式，比如draw一个circle，也可以用切好的圆形图片做背景或者写一个xml实现圆角功能等等。不过在项目中，如果我们有多个地方要把图片展示出圆形的，而且图片是从网络上取的，这种情况还一个个处理就麻烦了，我们可以定义个圆形图片组件RoundImageView，然后在要用的地方把RoundImageView当成ImageView一样使用就行了。我在最近做的项目中也用到了圆形图片，所以做个笔记，方便下次使用！ 首先看我们定义的RoundImageView:

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) {//这里要用到自定义属性TypedArray a = mContext.obtainStyledAttributes(attrs,R.styleable.RoundImageView);mBorderThickness = a.getDimensionPixelSize(R.styleable.RoundImageView_border_thickness, 0);mBorderOutsideColor = a.getColor(R.styleable.RoundImageView_border_outside_color,defaultColor);mBorderInsideColor = a.getColor(R.styleable.RoundImageView_border_inside_color, defaultColor);}@Overrideprotected void onDraw(Canvas canvas) {Drawable drawable = getDrawable();if (drawable == null) {return;}if (getWidth() == 0 || getHeight() == 0) {return;}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&amp;&amp; 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&amp;&amp; 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&amp;&amp; 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);bitmap = null;canvas.drawBitmap(roundBitmap, defaultWidth / 2 - radius, defaultHeight/ 2 - radius, null);}/*** 获取裁剪后的圆形图片*/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();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);}}

在res/values建一个attrs.xml文件，加入自定义属性字段

<?xml version="1.0" encoding="utf-8"?><resources>    <declare-styleable name="RoundImageView">        <attr name="border_thickness" format="dimension" />        <attr name="border_outside_color" format="color" />        <attr name="border_inside_color" format="color" />    </declare-styleable></resources>

最后就直接把这个RoundImageView看作ImageView在你需要用的地方用就可以了。