iOS添加虚线边框

_btnView.layer.cornerRadius = 6.0;
   
    CAShapeLayer *borderLayer = [CAShapeLayer layer];
    borderLayer.bounds = CGRectMake(0, 0, _btnView.width, _btnView.height);
    borderLayer.position = CGPointMake(CGRectGetMidX(_btnView.bounds), CGRectGetMidY(_btnView.bounds));
    borderLayer.path = [UIBezierPath bezierPathWithRoundedRect:borderLayer.bounds cornerRadius:6.0].CGPath;
    borderLayer.lineWidth = 9 / [[UIScreen mainScreen] scale];
    //虚线边框---小边框的长度
    borderLayer.lineDashPattern = @[@6, @3];//前边是虚线的长度，后边是虚线之间空隙的长度
    borderLayer.lineDashPhase = 0.1;
    //实线边框
    borderLayer.fillColor = [UIColor clearColor].CGColor;
    borderLayer.strokeColor = [UIColor redColor].CGColor;

    [ _btnView . layer addSublayer :borderLayer];