众所周知， UIImageView 在drawrect方法中是不走的，也就是继承UIImageView的子控件，无法在drawrect方法中重新绘制，因为该方法是失效的。
- (void)drawRect:(CGRect)rect {
// Drawing code
CGFloatwidth =CGRectGetWidth(rect);
CGFloatheight =CGRectGetHeight(rect);
CGFloatradius = width>height?height/2.0:width/2.0;
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddArc(path,NULL, width/2.0, height/2.0, radius,0,2*M_PI,YES);
CAShapeLayer *maskLayer = [CAShapeLayer layer];
maskLayer.frame= rect;
maskLayer.path= path;
self.layer.mask= maskLayer;
}
那么怎样才能让UIImageview绘制出圆形呢？需要让他走绘制的方法，如果不能走drawrect，那么采用他还会走什么方法呢？答案是layoutSubviews, 把方法写在layoutSubviews里面即可。
#import "HZRoundImageView.h"
@implementationHZRoundImageView
- (instancetype)initWithFrame:(CGRect)frame {
if(self= [superinitWithFrame:frame]) {
}
return self;
}
- (void)layoutSubviews {
CGRectrect =self.bounds;
// Drawing code
CGFloatwidth =CGRectGetWidth(rect);
CGFloatheight =CGRectGetHeight(rect);
CGFloatradius = width>height?height/2.0:width/2.0;
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddArc(path,NULL, width/2.0, height/2.0, radius,0,2*M_PI,YES);
CAShapeLayer *maskLayer = [CAShapeLayer layer];
maskLayer.frame= rect;
maskLayer.path= path;
self.layer.mask= maskLayer;
}
然后在其他地方调用, 无论是使用initWithFrame方法还是autolayout都可以变成圆形。
调用一个例子如下:
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[self initUI];
}
- (void)initUI {
HZRoundImageView *imageView = [[HZRoundImageView alloc]initWithFrame:CGRectMake(100,100,100,150)];
[self.view addSubview:imageView];
[imageView setBackgroundColor:[UIColor greenColor]];
[imageView setImage:[UIImageimageNamed:@"bbs_item0"]];
imageView.layer.masksToBounds=YES;
[imageView mas_makeConstraints:^(MASConstraintMaker*make) {
make.center.equalTo(self.view);
make.width.equalTo(self.view).multipliedBy(0.8);
make.height.equalTo(self.view).multipliedBy(0.8);
}];
}
效果如上图。
