最近在学习swift的过程中，看到了一些自定义UIBarButtonItem的例子，再此想和大家分享一下，废话不多说，先看下效果图：

Paste_Image.png

1 重写Button的titleLabel和imageView两个属性

class ItemLeftButton: UIButton {
    override func layoutSubviews() {
        super.layoutSubviews()
        let Offset: CGFloat = 15
        titleLabel?.sizeToFit()
        titleLabel?.frame = CGRectMake(-Offset, height - 15, width - Offset, (titleLabel?.height)!)
        titleLabel?.textAlignment = .Center
        imageView?.frame = CGRectMake(-Offset, 0, width - Offset, height - 15)
        imageView?.contentMode = .Center
    }
}

class ItemRightButton: UIButton {
    override func layoutSubviews() {
        super.layoutSubviews()
        let Offset: CGFloat = 15
        titleLabel?.sizeToFit()
        titleLabel?.frame = CGRectMake(Offset, height - 15, width + Offset, (titleLabel?.height)!)
        titleLabel?.textAlignment = .Center
        imageView?.frame = CGRectMake(Offset, 0, width + Offset, height - 15)
        imageView?.contentMode = UIViewContentMode.Center
    }
}

2 自定义UIBarButtonItem的方法

enum ItemButtonType: Int {
    case Left = 0
    case Right = 1
}

extension UIBarButtonItem {
    class func barButton(title: String, titleColor: UIColor, image: UIImage, hightLightImage: UIImage?, target: AnyObject?, action: Selector, type: ItemButtonType) -> UIBarButtonItem {
        var btn:UIButton = UIButton()
        if type == ItemButtonType.Left {
            btn = ItemLeftButton(type: .Custom)
        } else {
            btn = ItemRightButton(type: .Custom)
        }
        btn.setTitle(title, forState: .Normal)
        btn.setImage(image, forState: .Normal)
        btn.setTitleColor(titleColor, forState: .Normal)
        btn.setImage(hightLightImage, forState: .Highlighted)
        btn.addTarget(target, action: action, forControlEvents: .TouchUpInside)
        btn.frame = CGRectMake(0, 0, 60, 44)
        btn.titleLabel?.font = UIFont.systemFontOfSize(10)
        return UIBarButtonItem(customView: btn)
    }
    
    class func barButton(image: UIImage, target: AnyObject?, action: Selector) -> UIBarButtonItem {
        let btn = ItemLeftButton(type: .Custom)
        btn.setImage(image, forState: UIControlState.Normal)
        btn.imageView?.contentMode = UIViewContentMode.Center
        btn.addTarget(target, action: action, forControlEvents: UIControlEvents.TouchUpInside)
        btn.frame = CGRectMake(0, 0, 44, 44)
        return UIBarButtonItem(customView: btn)
    }
    
    class func barButton(title: String, titleColor: UIColor, target: AnyObject?, action: Selector) -> UIBarButtonItem {
        let btn = UIButton(frame: CGRectMake(0, 0, 60, 44))
        btn.setTitle(title, forState: .Normal)
        btn.setTitleColor(titleColor, forState: .Normal)
        btn.addTarget(target, action: action, forControlEvents: UIControlEvents.TouchUpInside)
        btn.titleLabel?.font = UIFont.systemFontOfSize(15)
        if title.characters.count == 2 {
            btn.contentEdgeInsets = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: -25)
        }
        return UIBarButtonItem(customView: btn)
    }
}

3 对UIView进行扩展

extension UIView {
    /// X值
    var x: CGFloat {
        return self.frame.origin.x
    }
    /// Y值
    var y: CGFloat {
        return self.frame.origin.y
    }
    /// 宽度
    var width: CGFloat {
        return self.frame.size.width
    }
    ///高度
    var height: CGFloat {
        return self.frame.size.height
    }
    var size: CGSize {
        return self.frame.size
    }
    var point: CGPoint {
        return self.frame.origin
    }
}

4 调用方法

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        navigationItem.leftBarButtonItem = UIBarButtonItem.barButton("扫一扫", titleColor: UIColor.blackColor(), image: UIImage(named: "icon_black_scancode")!, hightLightImage: nil, target: self, action: #selector(ViewController.leftItemClick), type: ItemButtonType.Left)
    }
    
    func leftItemClick() {
        print("扫一扫")
    }
}