为了达到美观的效果，项目中的所有图片显示都是圆角显示。然而Android的ImageView没有圆角属性，而让UI把所有图片都处理成圆角，也不合适。这里采用自定义的方法来自定义一个支持圆角的ImageView，然后在布局中引用这个类来布局就可以了。同时，该自定义ImageView还支持绘制圆形和椭圆形的ImageView。可以根据实际需要来选择。 这个代码是网上找的 和大家一起分享下
import android.content.Context;import android.graphics.*;import android.graphics.Bitmap.Config;import android.graphics.PorterDuff.Mode;import android.graphics.drawable.Drawable;import android.util.AttributeSet;import android.util.Log;import android.widget.ImageView;import java.lang.ref.WeakReference;/*** 使用Xfermode渲染方案实现圆角矩形、椭圆ImageView* @author caizhiming**/public class XCRoundImageViewByXfermode extends ImageView{//数据定义private Paint mPaint; private Xfermode mXfermode = new PorterDuffXfermode(Mode.DST_IN); private Bitmap mMaskBitmap; //用来做private int mRoundBorderRadius;//圆角大小private int mType;//类型：圆形、圆角或椭圆private WeakReference<Bitmap> mBufferBitmap;//使用缓存技术，避免每次都执行onDrawpublic static final int TYPE_CIRCLE = 1;//圆形public static final int TYPE_ROUND = 2;//圆角矩形public static final int TYPE_OVAL = 3;//椭圆形private static final int DEFAULT_ROUND_BORDER_RADIUS = 10;//默认圆角大小 //构造方法public XCRoundImageViewByXfermode(Context context){this(context, null);}public XCRoundImageViewByXfermode(Context context, AttributeSet attrs) {super(context, attrs);// TODO Auto-generated constructor stubmPaint = new Paint();mPaint.setAntiAlias(true);//设置消除锯齿mType = TYPE_ROUND;mRoundBorderRadius = DEFAULT_ROUND_BORDER_RADIUS;}/*** 测量view的大小*/@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {// TODO Auto-generated method stubsuper.onMeasure(widthMeasureSpec, heightMeasureSpec);//如果类型是圆形，则强制设置view的宽高一致，取宽高的较小值 if(mType == TYPE_CIRCLE){int width = Math.min(getMeasuredWidth(),getMeasuredHeight());setMeasuredDimension(width, width);}}/*** 绘制view的内容*/@Overrideprotected void onDraw(Canvas canvas) {// TODO Auto-generated method stub//从缓存中取出bitmapBitmap bmp = (mBufferBitmap == null ? null:mBufferBitmap.get());if(bmp == null || bmp.isRecycled()){//如果没有缓存存在的情况//获取drawableDrawable drawable = getDrawable();//获取drawable的宽高int dwidth = drawable.getIntrinsicWidth();int dheight = drawable.getIntrinsicHeight();Log.v("czm","dwidth="+dwidth+",width="+getWidth());if(null != drawable){bmp = Bitmap.createBitmap(getWidth(), getHeight(), Config.ARGB_8888); float scale = 1.0f;//创建画布Canvas drawCanvas = new Canvas(bmp);//按照bitmap的宽高，以及view的宽高，计算缩放比例；因为设置的src宽高//比例可能和imageview的宽高比例不同，这里我们不希望图片失真； if(mType == TYPE_CIRCLE) {//如果是圆形 scale = getWidth() * 1.0F / Math.min(dwidth, dheight); }else if (mType == TYPE_ROUND || mType == TYPE_OVAL) {//如果是圆角矩形或椭圆 // 如果图片的宽或者高与view的宽高不匹配，计算出需要缩放的比例；//缩放后的图片的宽高，一定要大于我们view的宽高；所以我们这里取大值； scale = Math.max(getWidth() * 1.0f / dwidth, getHeight() * 1.0f / dheight); }Log.v("czm","scale="+scale);//根据缩放比例，设置bounds，即相当于做缩放图片 drawable.setBounds(0, 0, (int)(scale * dwidth), (int)(scale * dheight));drawable.draw(drawCanvas);//获取bitmap，即圆形、圆角或椭圆的bitmapif(mMaskBitmap == null || mMaskBitmap.isRecycled()){mMaskBitmap = getDrawBitmap();}//为paint设置Xfermode 渲染模式mPaint.reset();mPaint.setFilterBitmap(false);mPaint.setXfermode(mXfermode);//绘制不同形状drawCanvas.drawBitmap(mMaskBitmap, 0, 0,mPaint);mPaint.setXfermode(null);//将准备好的bitmap绘制出来 canvas.drawBitmap(bmp, 0, 0, null); //bitmap缓存起来，避免每次调用onDraw，分配内存 mBufferBitmap = new WeakReference<Bitmap>(bmp); }}else{//如果缓存还存在的情况mPaint.setXfermode(null); canvas.drawBitmap(bmp, 0.0f, 0.0f, mPaint); return; }}/*** 绘制不同的图形Bitmap*/private Bitmap getDrawBitmap(){Bitmap bitmap = Bitmap.createBitmap(getWidth(), getHeight(), Config.ARGB_8888);Canvas canvas = new Canvas(bitmap); Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG); paint.setColor(Color.BLACK); if(mType == TYPE_CIRCLE){//绘制圆形 canvas.drawCircle(getWidth() / 2, getWidth() / 2, getWidth() / 2, paint); }else if(mType == TYPE_ROUND) {//绘制圆角矩形canvas.drawRoundRect(new RectF(0, 0, getWidth(), getHeight()), mRoundBorderRadius, mRoundBorderRadius, paint); }else if(mType == TYPE_OVAL ){//绘制椭圆canvas.drawOval(new RectF(0, 0, getWidth(), getHeight()), mPaint);}return bitmap; }/*** 因为使用了缓存技术，所以需要在invalidate中做些回收释放资源的处理*/@Overridepublic void invalidate() {// TODO Auto-generated method stubmBufferBitmap = null;if(mMaskBitmap != null){mMaskBitmap.recycle();mMaskBitmap = null;}super.invalidate();}public int getRoundBorderRadius() {return mRoundBorderRadius;}public void setRoundBorderRadius(int mRoundBorderRadius) {if(this.mRoundBorderRadius != mRoundBorderRadius){this.mRoundBorderRadius = mRoundBorderRadius;invalidate();}}public int getType() {return this.mType;}public void setType(int mType) {if(this.mType != mType){this.mType = mType;invalidate();}}}
效果如图
