自定义的圆角ImageView

在一些应用中经常会看到一些圆角的图片，很是漂亮，于是上网查资料试着自己做一个圆角的ImageView。

先上效果图：

做法步骤：

自定义一个类继承ImageView：

public class RoundRectImageView extends android.support.v7.widget.AppCompatImageView{}类里还需要一个画笔Paint：

private Paint paint;下面是具体的画法，首先绘制圆角矩形图片：

@Override protected void onDraw(Canvas canvas) { Drawable drawable = getDrawable(); if (null != drawable) { Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap(); Bitmap b = getRoundBitmap(bitmap, 20); final Rect rectSrc = new Rect(0, 0, b.getWidth(), b.getHeight()); final Rect rectDest = new Rect(0,0,getWidth(),getHeight()); paint.reset(); canvas.drawBitmap(b, rectSrc, rectDest, paint); } else { super.onDraw(canvas); } } 然后是获取圆角矩形图片：

private Bitmap getRoundBitmap(Bitmap bitmap, int roundPx) { Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888); Canvas canvas = new Canvas(output); final int color = 0xff222222; final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight()); final RectF rectF = new RectF(rect); paint.setAntiAlias(true); canvas.drawARGB(0, 0, 0, 0); paint.setColor(color); canvas.drawRoundRect(rectF, roundPx, roundPx, paint); paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN)); canvas.drawBitmap(bitmap, rect, rect, paint); return output; }需要用到圆角图片的时候在xml文件里直接写就行了：

<com.liuyuntian.mediaplayer.customview.RoundRectImageView android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1" android:scaleType="fitXY" android:src="@mipmap/flower_img" /> 圆角图片制作完成。