Android自定义控件之圆形头像
自定义控件也看了很多，但是感觉始终写不出来很牛逼的控件。看来还是自己火候不到位啊！平时也老玩，没有下苦功夫。每当看到爱哥、鸿洋等大牛的博客，仍是我继续努力的方向啊！今天准备做一个自定义控件圆形的ImageView，但是上网看看，发现一位基友已经写过了，但是我还是参照他的谢谢，当做练笔吧！
预备知识点
- Canvas的基本用法，比如绘制圆形：canvas.drawCircle()，绘制Bitmap位图 canvas.drawBitmap
- Paint的基本用法，比如paint.setXfermode的基本使用，了解Mode的效果
需要的基本知识就是这样，其实自定义控件在怎么说，方法也就那么多，关键是根据需求的灵活运用，孙悟空就72变，但是足以对付妖魔千千万。
思路分析
首先我们有一张图，我们在xml布局文件中设置控件显示的大小，一般情况下，他俩是不肯能大小相等的，所以我们就必须控制这张图片的哪些内容进行显示，这部分内容是我们控制进行处理，我们控制可以显示去掉两边的部分，也可以将整张图片进行压缩显示整张图片，后面我们都可以进行尝试。其次，我们要确定我们如何得到圆形，方法是利用setXfermode的设置进行裁剪得到。基本的要点说清楚了，我们就开始实现吧！
资源图效果： 
效果图
步骤
1、创建工程CircleImageView，新建类CircleImageView继承ImageView，这样我们就开始开发了。重写构造函数，并在构造函数中进行初始化的工作，同时重写onMeasure方法。
<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background: transparent;"> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">CircleImageView</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">extends</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ImageView</span> {</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 控件默认长、宽 </span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> defaultWidth = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">100</span>;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> defaultHeight = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">100</span>;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> Paint paint;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-title" style="box-sizing: border-box;">CircleImageView</span>(Context context, AttributeSet attrs) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>(context, attrs);
paint = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Paint();
paint.setAntiAlias(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>);
paint.setFilterBitmap(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>);
paint.setDither(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>);
}
<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">protected</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onMeasure</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> widthMeasureSpec, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> heightMeasureSpec) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> widthSize = MeasureSpec.getSize(widthMeasureSpec);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> widthMode = MeasureSpec.getMode(widthMeasureSpec);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> heightSize = MeasureSpec.getSize(heightMeasureSpec);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> heightMode = MeasureSpec.getMode(heightMeasureSpec);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(widthMode == MeasureSpec.AT_MOST || heightMode == MeasureSpec.AT_MOST){
widthSize = (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span>) (<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">100</span> * getResources().getDisplayMetrics().density);
heightSize = (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span>) (<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">100</span> * getResources().getDisplayMetrics().density);
}
setMeasuredDimension(widthSize, heightSize);
}
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li></ul>
我们初始化我们的画笔paint对象，并进行了一些属性设置，同时定义了控件的默认长宽，我们重写onMeasure方法，为了防止控件设置为wrap_content时的显示问题，我们统一处理为100dp的大小。
2、重写onDraw方法，进行我们图片的处理逻辑和绘制。这样就了所有的处理工作，我直接贴出所有代码。
<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">CircleImageView</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">extends</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ImageView</span> {</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 控件默认长、宽 </span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> defaultWidth = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">100</span>;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> defaultHeight = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">100</span>;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> Paint paint;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-title" style="box-sizing: border-box;">CircleImageView</span>(Context context, AttributeSet attrs) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>(context, attrs);
paint = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Paint();
paint.setAntiAlias(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>);
paint.setFilterBitmap(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>);
paint.setDither(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>);
}
<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">protected</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onMeasure</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> widthMeasureSpec, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> heightMeasureSpec) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> widthSize = MeasureSpec.getSize(widthMeasureSpec);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> widthMode = MeasureSpec.getMode(widthMeasureSpec);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> heightSize = MeasureSpec.getSize(heightMeasureSpec);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> heightMode = MeasureSpec.getMode(heightMeasureSpec);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(widthMode == MeasureSpec.AT_MOST || heightMode == MeasureSpec.AT_MOST){
widthSize = (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span>) (<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">100</span> * getResources().getDisplayMetrics().density);
heightSize = (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span>) (<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">100</span> * getResources().getDisplayMetrics().density);
}
setMeasuredDimension(widthSize, heightSize);
}
<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">protected</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onDraw</span>(Canvas canvas) {
Drawable drawable = getDrawable() ;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (drawable == <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span>;
}
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (getWidth() == <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span> || getHeight() == <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span>;
}
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.measure(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (drawable.getClass() == NinePatchDrawable.class)
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span>;
Bitmap b = ((BitmapDrawable) drawable).getBitmap();
Bitmap bitmap = b.copy(Bitmap.Config.ARGB_8888, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>);
defaultWidth = getWidth();
defaultHeight = getHeight();
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//计算显示圆形的半径，为保证圆形，取图片的长宽小的一半作为圆形</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> radius = (defaultWidth < defaultHeight ? defaultWidth : defaultHeight) / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//获取我们处理后的圆形图片</span>
Bitmap roundBitmap = getCroppedRoundBitmap(bitmap, radius);
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//绘制图片进行显示</span>
canvas.drawBitmap(roundBitmap, defaultWidth / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span> - radius, defaultHeight / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span> - radius, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>);
}
<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**
* 获取裁剪后的圆形图片
*<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @param</span> radius半径
*/</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> Bitmap <span class="hljs-title" style="box-sizing: border-box;">getCroppedRoundBitmap</span>(Bitmap bmp, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> radius) {
Bitmap scaledSrcBmp;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> diameter = radius * <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//对图片进行处理，获取我们需要的*部分</span>
Bitmap squareBitmap = getCenterBitmap(bmp);
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//将图片缩放到需要的圆形比例大小</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (squareBitmap.getWidth() != diameter || squareBitmap.getHeight() != diameter) {
scaledSrcBmp = Bitmap.createScaledBitmap(squareBitmap, diameter,diameter, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>);
} <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> {
scaledSrcBmp = squareBitmap;
}
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//创建一个我们输出的对应</span>
Bitmap output = Bitmap.createBitmap(scaledSrcBmp.getWidth(),
scaledSrcBmp.getHeight(),
Config.ARGB_8888);
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//在output上进行绘画</span>
Canvas canvas = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Canvas(output);
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//创建裁剪的矩形</span>
Rect rect = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Rect(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>, scaledSrcBmp.getWidth(),scaledSrcBmp.getHeight());
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//绘制dest目标区域</span>
canvas.drawCircle(scaledSrcBmp.getWidth() / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>,
scaledSrcBmp.getHeight() / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>,
scaledSrcBmp.getWidth() / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>,
paint);
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//设置xfermode模式</span>
paint.setXfermode(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> PorterDuffXfermode(Mode.SRC_IN));
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//绘制src源区域</span>
canvas.drawBitmap(scaledSrcBmp, rect, rect, paint);
bmp.recycle();
squareBitmap.recycle();
scaledSrcBmp.recycle();
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> output;
}
<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**
* 截图图片
*<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @param</span> bitmap
* 图片资源的Bitmap
*<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @return</span>
*/</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> Bitmap <span class="hljs-title" style="box-sizing: border-box;">getCenterBitmap</span>(Bitmap bitmap){
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 为了防止图片宽高不相等，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 </span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> bmpWidth = bitmap.getWidth();
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> bmpHeight = bitmap.getHeight();
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> squareWidth = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>, squareHeight = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> x = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>, y = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
Bitmap squareBitmap;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (bmpHeight > bmpWidth) {<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 高大于宽 </span>
squareWidth = squareHeight = bmpWidth;
x = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
y = (bmpHeight - bmpWidth) / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 截取正方形图片 ，从(bmpHeight - bmpWidth) / 2处开始截取</span>
squareBitmap = Bitmap.createBitmap(bitmap, x, y, squareWidth, squareHeight);
} <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (bmpHeight < bmpWidth) {<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 宽大于高 </span>
squareWidth = squareHeight = bmpHeight;
x = (bmpWidth - bmpHeight) / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>;
y = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
squareBitmap = Bitmap.createBitmap(bitmap, x, y, squareWidth,squareHeight);
} <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> {
squareBitmap = bitmap;
}
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> squareBitmap;
}
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li><li style="box-sizing: border-box; padding: 0px 5px;">46</li><li style="box-sizing: border-box; padding: 0px 5px;">47</li><li style="box-sizing: border-box; padding: 0px 5px;">48</li><li style="box-sizing: border-box; padding: 0px 5px;">49</li><li style="box-sizing: border-box; padding: 0px 5px;">50</li><li style="box-sizing: border-box; padding: 0px 5px;">51</li><li style="box-sizing: border-box; padding: 0px 5px;">52</li><li style="box-sizing: border-box; padding: 0px 5px;">53</li><li style="box-sizing: border-box; padding: 0px 5px;">54</li><li style="box-sizing: border-box; padding: 0px 5px;">55</li><li style="box-sizing: border-box; padding: 0px 5px;">56</li><li style="box-sizing: border-box; padding: 0px 5px;">57</li><li style="box-sizing: border-box; padding: 0px 5px;">58</li><li style="box-sizing: border-box; padding: 0px 5px;">59</li><li style="box-sizing: border-box; padding: 0px 5px;">60</li><li style="box-sizing: border-box; padding: 0px 5px;">61</li><li style="box-sizing: border-box; padding: 0px 5px;">62</li><li style="box-sizing: border-box; padding: 0px 5px;">63</li><li style="box-sizing: border-box; padding: 0px 5px;">64</li><li style="box-sizing: border-box; padding: 0px 5px;">65</li><li style="box-sizing: border-box; padding: 0px 5px;">66</li><li style="box-sizing: border-box; padding: 0px 5px;">67</li><li style="box-sizing: border-box; padding: 0px 5px;">68</li><li style="box-sizing: border-box; padding: 0px 5px;">69</li><li style="box-sizing: border-box; padding: 0px 5px;">70</li><li style="box-sizing: border-box; padding: 0px 5px;">71</li><li style="box-sizing: border-box; padding: 0px 5px;">72</li><li style="box-sizing: border-box; padding: 0px 5px;">73</li><li style="box-sizing: border-box; padding: 0px 5px;">74</li><li style="box-sizing: border-box; padding: 0px 5px;">75</li><li style="box-sizing: border-box; padding: 0px 5px;">76</li><li style="box-sizing: border-box; padding: 0px 5px;">77</li><li style="box-sizing: border-box; padding: 0px 5px;">78</li><li style="box-sizing: border-box; padding: 0px 5px;">79</li><li style="box-sizing: border-box; padding: 0px 5px;">80</li><li style="box-sizing: border-box; padding: 0px 5px;">81</li><li style="box-sizing: border-box; padding: 0px 5px;">82</li><li style="box-sizing: border-box; padding: 0px 5px;">83</li><li style="box-sizing: border-box; padding: 0px 5px;">84</li><li style="box-sizing: border-box; padding: 0px 5px;">85</li><li style="box-sizing: border-box; padding: 0px 5px;">86</li><li style="box-sizing: border-box; padding: 0px 5px;">87</li><li style="box-sizing: border-box; padding: 0px 5px;">88</li><li style="box-sizing: border-box; padding: 0px 5px;">89</li><li style="box-sizing: border-box; padding: 0px 5px;">90</li><li style="box-sizing: border-box; padding: 0px 5px;">91</li><li style="box-sizing: border-box; padding: 0px 5px;">92</li><li style="box-sizing: border-box; padding: 0px 5px;">93</li><li style="box-sizing: border-box; padding: 0px 5px;">94</li><li style="box-sizing: border-box; padding: 0px 5px;">95</li><li style="box-sizing: border-box; padding: 0px 5px;">96</li><li style="box-sizing: border-box; padding: 0px 5px;">97</li><li style="box-sizing: border-box; padding: 0px 5px;">98</li><li style="box-sizing: border-box; padding: 0px 5px;">99</li><li style="box-sizing: border-box; padding: 0px 5px;">100</li><li style="box-sizing: border-box; padding: 0px 5px;">101</li><li style="box-sizing: border-box; padding: 0px 5px;">102</li><li style="box-sizing: border-box; padding: 0px 5px;">103</li><li style="box-sizing: border-box; padding: 0px 5px;">104</li><li style="box-sizing: border-box; padding: 0px 5px;">105</li><li style="box-sizing: border-box; padding: 0px 5px;">106</li><li style="box-sizing: border-box; padding: 0px 5px;">107</li><li style="box-sizing: border-box; padding: 0px 5px;">108</li><li style="box-sizing: border-box; padding: 0px 5px;">109</li><li style="box-sizing: border-box; padding: 0px 5px;">110</li><li style="box-sizing: border-box; padding: 0px 5px;">111</li><li style="box-sizing: border-box; padding: 0px 5px;">112</li><li style="box-sizing: border-box; padding: 0px 5px;">113</li><li style="box-sizing: border-box; padding: 0px 5px;">114</li><li style="box-sizing: border-box; padding: 0px 5px;">115</li><li style="box-sizing: border-box; padding: 0px 5px;">116</li><li style="box-sizing: border-box; padding: 0px 5px;">117</li><li style="box-sizing: border-box; padding: 0px 5px;">118</li></ul>
代码中的注释已经很详细了，我们先说说我们图片展示内容处理代码，即getCenterBitmap函数的功能。我们知道图片的大小不外乎三种情况：宽>高，宽<高，宽=高。
（1）、宽>高：
（2）、宽<高：
这部分的代码原理就是上面描述的这样，所以我们的代码就是纯粹的实现我们想要的效果，当然我们也可以根据自己的需求进行变换处理。
其次就是大家对
<code class="hljs avrasm has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background: transparent;">paint<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.setXfermode</span>(new PorterDuffXfermode(Mode<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.SRC</span>_IN))<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
的使用理解，只要懂的理解就应该没问题，是不是很简单。
这样一个简单的自定义控件就基本完成了，是不是很nice。
如何添加给我们的圆形控件添加上边框？
前面我们已经实现了圆形控件的展示，那么我们如果想给我们的圆形控件添加边框怎么实现呢？这就需要利用到我们的自定义属性的相关知识。让我们一些来实现看。当然，上面的CircleImageView类是我们继续开发的基础，我们可以直接copy里面的代码出来新建一个类：CircleImageViewWithBorder。
1、我们在res/values目录下创建名称为attrs的资源文件，添加我们的自定义属性。
<code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">resources</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">declare-styleable</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">name</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"CircleImageView"</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">attr</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">name</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"border_size"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">format</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"dimension"</span> /></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">attr</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">name</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"border_color"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">format</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"color"</span> /></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">declare-styleable</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">resources</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li></ul>
在xml文件中使用自定义属性，注意，需要添加命名空间
xmlns:dsw="http://schemas.android.com/apk/res/com.dsw.circleimageview"
mainactivity中的布局文件
<code class="hljs avrasm has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background: transparent;"><LinearLayout xmlns:android=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"http://schemas.android.com/apk/res/android"</span>
xmlns:dsw=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"http://schemas.android.com/apk/res/com.dsw.circleimageview"</span>
xmlns:tools=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"http://schemas.android.com/tools"</span>
android:layout_width=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"match_parent"</span>
android:layout_height=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"match_parent"</span>
android:orientation=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"vertical"</span>
tools:context=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"com.dsw.circleimageview.MainActivity"</span> >
<<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">com</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.dsw</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.circleimageview</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.CircleImageView</span>
android:layout_width=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"100dp"</span>
android:layout_height=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"100dp"</span>
android:layout_margin=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"20dp"</span>
android:src=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"@drawable/test"</span>/>
<<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">com</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.dsw</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.circleimageview</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.CircleImageViewWithBorder</span>
android:layout_width=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"100dp"</span>
android:layout_height=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"100dp"</span>
android:layout_margin=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"20dp"</span>
android:src=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"@drawable/test"</span>
dsw:border_color=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"#0000ff"</span>
dsw:border_size=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"1dp"</span>
/>
</LinearLayout></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li></ul>
2、新增成员变量，边框的宽度和颜色，以及获取自定义属性的获取。
<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> Context mContext;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> defaultColor = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0xFFFFFFFF</span>;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 边框的颜色</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> mBordeColor = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//边框的宽度</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> mBorderWidth = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">/*
* 获取自定义属性
*/</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">setCustomAttributes</span>(AttributeSet attrs) {
TypedArray typeArray = mContext.obtainStyledAttributes(attrs,R.styleable.CircleImageView);
mBorderWidth = typeArray.getDimensionPixelSize(R.styleable.CircleImageView_border_size, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>);
mBordeColor = typeArray.getColor(R.styleable.CircleImageView_border_color,defaultColor);
typeArray.recycle();
} </code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li></ul>
3、我们已经获取了我们设置的属性，注意此时，由于已经有了边框，所以绘制圆的半径必然会变化，我们就需要重新进行计算我们的半径，然后绘制出这个圆就可以了。我们知道，我们采用的大小是与我们设定大小的矩形相切的最大圆，所以原来的半径计算已经包含了边框的宽度，我们只要减去即可。
<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//整除情况下的半径</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> radiusNomal = (defaultWidth < defaultHeight ? defaultWidth : defaultHeight) / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//去掉边框的宽度后，图片展示的半径</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> radius = radiusNomal -mBorderWidth/<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//绘制边框的半径</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> radiusBorder = radius;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//绘制边框圆</span>
drawCircleBorder(canvas,radiusBorder,mBordeColor);
<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**
* 边缘画圆
*/</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">drawCircleBorder</span>(Canvas canvas, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> radius, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> color) {
Paint paint = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Paint();
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">/* 去锯齿 */</span>
paint.setAntiAlias(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>);
paint.setFilterBitmap(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>);
paint.setDither(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>);
paint.setColor(color);
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">/* 设置paint的 style 为STROKE：空心 */</span>
paint.setStyle(Paint.Style.STROKE);
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">/* 设置paint的外框宽度 */</span>
paint.setStrokeWidth(mBorderWidth);
canvas.drawCircle(defaultWidth / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>, defaultHeight / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>, radius, paint);
} </code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li></ul>
至此，我们就对添加边框完成了。
效果图： 
总结
我们开篇的时候说过，我们现在展示的是切图，是我们自己抽取的原图中的*部分，那么如果要获取原图呢？我们只需要将getCenterBitmap方法中的处理去掉，然后返回原图即可。
<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background: transparent;"> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> Bitmap <span class="hljs-title" style="box-sizing: border-box;">getCenterBitmap</span>(Bitmap bitmap){
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> bitmap;
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>
效果图： 
我们通过setXfermode方法进行裁剪，其实canvas类中已经有一个clip方法，我们只要指定路径同样可以进行裁剪，网上也有例子，有兴趣可以看下。欢迎留言探讨
参考文档：
Android圆形图片–自定义控件
android 实现圆形imageView,Circle imageView.
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