view的边框线(border)默认显示在最上面的坑
绘制一个圆角矩形，然后在上面盖上一个图片，
line@2x.png
想实现如下效果：
理想效果
编写代码如下：
self.layer.borderWidth = 1;
self.layer.borderColor = borderColor.CGColor;
self.layer.backgroundColor = backColor.CGColor;
self.layer.cornerRadius=5;
UIImageView *imgview1=[[UIImageView alloc]initWithImage:_IMAGE(@"invitation_reward_bg_line1@2x.png", nil)];
[selfaddSubview:imgview1];
[imgview1mas_makeConstraints:^(MASConstraintMaker *make) {
make.top.mas_equalTo(88);
make.left.mas_equalTo(0);
make.right.mas_equalTo(0);
make.height.mas_equalTo(20);
}];
结果出来的效果是这样的：
错误效果
发现border居然没有遮盖住，刚开始还以为是坐标没对好，将left改成-1看看，还是不行，还以为是图片问题，直接添加一个view，发现在border始终在上面：
测试效果
点击查看borderWidth的属性：
/* The width of the layer's border, inset from the layer bounds. The
* border is composited above the layer's content and sublayers and
* includes the effects of the `cornerRadius' property. Defaults to
* zero. Animatable. */
发现上面注明了：border is composited above the layer's content and sublayers....
怪不得！
那要怎么绘制border，又能实现被遮盖，从而显示成凹进去的效果，其实只需要改变border的绘制方式即可，封了一个绘制圆角及边框线的方法如下：
-(void)roundCornerWithCornerRadii:(CGSize)cornerRadii andCorners:(UIRectCorner)corners andBordWidth:(CGFloat)bdWidth andBordColor:(UIColor*)bdColor{
UIBezierPath *maskPath=[UIBezierPath bezierPathWithRoundedRect:self.bounds byRoundingCorners:corners cornerRadii: cornerRadii];
CAShapeLayer *maskLayer = [CAShapeLayer layer];
maskLayer.path= maskPath.CGPath;
self.layer.mask= maskLayer;
//如果有边框，此时边框不能用self.layer.border来设置会有出入，而应该：
if(bdWidth && bdColor) {
//重复执行roundCornerWithCornerRadii，如果有border的话，会导致boder重叠错位,故添加boder前先清除之前的添加的
for(CAShapeLayer*borderLayerin[self.layersublayers]) {
if([borderLayerisKindOfClass:[CAShapeLayerclass]]) {
[borderLayerremoveFromSuperlayer];
break;
}
}
CAShapeLayer *borderLayer=[CAShapeLayer layer];
borderLayer.path= maskPath.CGPath;
borderLayer.fillColor= [UIColor clearColor].CGColor;
borderLayer.strokeColor= [bdColorCGColor];
borderLayer.lineWidth= bdWidth;
borderLayer.frame=self.bounds;
[self.layeraddSublayer:borderLayer];
}
}
最终效果如下：
正确效果
注：通过UIBezierPath绘制圆角和边框线，好处多多，还能优化UI性能哦！
