指定UIView的某几个角为圆角

UIView *view2 = [[UIView alloc] initWithFrame:CGRectMake(30, 65,self.view.bounds.size.width-60, 300)];
view2.backgroundColor = [UIColor redColor];
[self.view addSubview:view2];

UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:view2.bounds byRoundingCorners:UIRectCornerTopLeft | UIRectCornerTopRight cornerRadii:CGSizeMake(6, 6)];
CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
maskLayer.frame = view2.bounds;
maskLayer.path = maskPath.CGPath;
view2.layer.mask = maskLayer;

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