java类如下：
import android.content.Context;import android.content.res.TypedArray;import android.graphics.Bitmap;import android.graphics.Bitmap.Config;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Path;import android.graphics.PorterDuff;import android.graphics.PorterDuffXfermode;import android.graphics.RectF;import android.util.AttributeSet;import android.widget.ImageView;import cn.dotcreate.tt.R;public class RoundAngleImageView extends ImageView {private Paint paint;private int roundWidth = 5;private int roundHeight = 5;private Paint paint2;public RoundAngleImageView(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);init(context, attrs);}public RoundAngleImageView(Context context, AttributeSet attrs) {super(context, attrs);init(context, attrs);}public RoundAngleImageView(Context context) {super(context);init(context, null);}private void init(Context context, AttributeSet attrs) {if(attrs != null) { TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.RoundAngleImageView); roundWidth= a.getDimensionPixelSize(R.styleable.RoundAngleImageView_roundWidth, roundWidth);roundHeight= a.getDimensionPixelSize(R.styleable.RoundAngleImageView_roundHeight, roundHeight);}else {float density = context.getResources().getDisplayMetrics().density;roundWidth = (int) (roundWidth*density);roundHeight = (int) (roundHeight*density);} paint = new Paint();paint.setColor(Color.WHITE);paint.setAntiAlias(true);paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OUT));paint2 = new Paint();paint2.setXfermode(null);}@Overridepublic void draw(Canvas canvas) {Bitmap bitmap = Bitmap.createBitmap(getWidth(), getHeight(), Config.ARGB_8888);Canvas canvas2 = new Canvas(bitmap);super.draw(canvas2);drawLiftUp(canvas2);drawRightUp(canvas2);drawLiftDown(canvas2);drawRightDown(canvas2);canvas.drawBitmap(bitmap, 0, 0, paint2);bitmap.recycle();}private void drawLiftUp(Canvas canvas) {Path path = new Path();path.moveTo(0, roundHeight);path.lineTo(0, 0);path.lineTo(roundWidth, 0);path.arcTo(new RectF(0, 0, roundWidth*2, roundHeight*2), -90, -90);path.close();canvas.drawPath(path, paint);}private void drawLiftDown(Canvas canvas) {Path path = new Path();path.moveTo(0, getHeight()-roundHeight);path.lineTo(0, getHeight());path.lineTo(roundWidth, getHeight());path.arcTo(new RectF(0, getHeight()-roundHeight*2, 0+roundWidth*2, getHeight()),90, 90);path.close();canvas.drawPath(path, paint);}private void drawRightDown(Canvas canvas) {Path path = new Path();path.moveTo(getWidth()-roundWidth, getHeight());path.lineTo(getWidth(), getHeight());path.lineTo(getWidth(), getHeight()-roundHeight);path.arcTo(new RectF(getWidth()-roundWidth*2, getHeight()-roundHeight*2, getWidth(), getHeight()), 0, 90);path.close();canvas.drawPath(path, paint);}private void drawRightUp(Canvas canvas) {Path path = new Path();path.moveTo(getWidth(), roundHeight);path.lineTo(getWidth(), 0);path.lineTo(getWidth()-roundWidth, 0);path.arcTo(new RectF(getWidth()-roundWidth*2, 0, getWidth(), 0+roundHeight*2), -90, 90);path.close();canvas.drawPath(path, paint);}}
定义一个attr.xml的文件，放在values目录下面，内容如下：
<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="RoundAngleImageView">
<attr name="roundWidth" format="dimension" />
<attr name="roundHeight" format="dimension" />
</declare-styleable>
</resources>
使用示例如下：
先要声明属性的名字空间：
然后再写跟一般定义View一样：
<cn.dotcreate.tt.ui.RoundAngleImageViewandroid:id="@+id/headIV"
android:layout_width="75dp"
android:layout_height="75dp"
android:layout_centerVertical="true"
android:layout_marginLeft="2dp"
app:roundWidth="10dp"
app:roundHeight="10dp"
android:src="@drawable/default_head_icon" />
效果如图：
