// 通过绘制实现 圆角，适用所有view
public class CircleWebview extends WebView {
public CircleWebview(Context context) {
this(context, null);
}

public CircleWebview(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
}

public CircleWebview(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    init(context);
}

private float vRadius=4;
private int vWidth;
private int vHeight;
private int x;
private int y;
private Paint paint1;
private Paint paint2;

private void init(Context context) {
    paint1 = new Paint();
    paint1.setColor(Color.WHITE);
    paint1.setAntiAlias(true);
    paint1.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OUT));
    //
    paint2 = new Paint();
    paint2.setXfermode(null);
}

public void setRadius(float radius) {
    vRadius = radius;
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    vWidth = getMeasuredWidth();
    vHeight = getMeasuredHeight();
}

@Override
public void draw(Canvas canvas) {

    x = this.getScrollX();
    y = this.getScrollY();
    Bitmap bitmap = Bitmap.createBitmap(x + vWidth, y + vHeight,
            Bitmap.Config.ARGB_8888);
    Canvas canvas2 = new Canvas(bitmap);
    super.draw(canvas2);
    drawLeftUp(canvas2);
    drawRightUp(canvas2);
    drawLeftDown(canvas2);
    drawRightDown(canvas2);
    canvas.drawBitmap(bitmap, 0, 0, paint2);
    bitmap.recycle();
}

private void drawLeftUp(Canvas canvas) {
    Path path = new Path();
    path.moveTo(x, vRadius);
    path.lineTo(x, y);
    path.lineTo(vRadius, y);
    path.arcTo(new RectF(x, y, x + vRadius * 2, y + vRadius * 2), -90, -90);
    path.close();
    canvas.drawPath(path, paint1);
}


private void drawLeftDown(Canvas canvas) {
    Path path = new Path();
    path.moveTo(x, y + vHeight - vRadius);
    path.lineTo(x, y + vHeight);
    path.lineTo(x + vRadius, y + vHeight);
    path.arcTo(new RectF(x, y + vHeight - vRadius * 2,
            x + vRadius * 2, y + vHeight), 90, 90);
    path.close();
    canvas.drawPath(path, paint1);
}


private void drawRightDown(Canvas canvas) {
    Path path = new Path();
    path.moveTo(x + vWidth - vRadius, y + vHeight);
    path.lineTo(x + vWidth, y + vHeight);
    path.lineTo(x + vWidth, y + vHeight - vRadius);
    path.arcTo(new RectF(x + vWidth - vRadius * 2, y + vHeight
            - vRadius * 2, x + vWidth, y + vHeight), 0, 90);
    path.close();
    canvas.drawPath(path, paint1);
}


private void drawRightUp(Canvas canvas) {
    Path path = new Path();
    path.moveTo(x + vWidth, y + vRadius);
    path.lineTo(x + vWidth, y);
    path.lineTo(x + vWidth - vRadius, y);
    path.arcTo(new RectF(x + vWidth - vRadius * 2, y, x + vWidth,
            y + vRadius * 2), -90, 90);
    path.close();
    canvas.drawPath(path, paint1);
}

}