IBDesignable UIButton子类

Question

我正在尝试实现一个简单的UIButton子类，即IBDesignable。我希望能够从Interface中为控件的每个状态设置颜色。我知道这在IBInspectable关键字中是可能的。当在状态属性上使用KVO时，我遇到了IB崩溃的问题。IBDesignable调试器在deinit上崩溃。有人知道我怎么能和KVO和IBDesignable一起工作吗？

@IBDesignable
class UIButtonActionButton: UIButton {

    @IBInspectable var defaultColour: UIColor = UIColor.blueColor() {
        didSet {
            self.setNeedsDisplay()
        } 
    }

    @IBInspectable var selectedColour: UIColor = UIColor.blueColor()

    @IBInspectable var disabledColour: UIColor = UIColor.grayColor()

    required init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        self._setup()
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        self._setup()
    }


    private func _setup(){
        self.addObserver(self, forKeyPath: "state", options: NSKeyValueObservingOptions.New, context: nil)
        self.layer.cornerRadius = 5.0
        self.layer.masksToBounds = true
    }

    override func observeValueForKeyPath(keyPath: String, ofObject object: AnyObject, change: [NSObject : AnyObject], context: UnsafeMutablePointer<Void>) {
        self.setNeedsDisplay()
    }

    override func drawRect(rect: CGRect) {
        super.drawRect(rect)
        let context = UIGraphicsGetCurrentContext()

        if self.highlighted {
            CGContextSetFillColorWithColor(context, selectedColour.CGColor)
            CGContextFillRect(context, self.bounds)
        } else if self.state == UIControlState.Disabled {
            CGContextSetFillColorWithColor(context, disabledColour.CGColor)
            CGContextFillRect(context, self.bounds)
        } else {
            CGContextSetFillColorWithColor(context, defaultColour.CGColor)
            CGContextFillRect(context, self.bounds)
        }
    }

    deinit {
        self.removeObserver(self, forKeyPath: "state", context: nil)
    }

}

Answer 1

我有类似的问题，问题是init()方法，它在重构我的代码之后导致了崩溃，它的工作原理就像一种魅力。也许它能帮到你：

#if !TARGET_INTERFACE_BUILDER
required init(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    self._setup()
}
#endif

override func prepareForInterfaceBuilder() {
    self._setup()
}

Answer 2

对于Xcode 7.2，@IBDesignable UIButton Subclass的通用代码如下所示：

import UIKit

@IBDesignable class MyButton: UIButton {

    //this init fires usually called, when storyboards UI objects created:
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        self.setupViews()
    }

    //This method is called during programmatic initialisation
    override init(frame: CGRect) {
        super.init(frame: frame)
        setupViews()
    }


    func setupViews() {
        //your common setup goes here
    }

    //required method to present changes in IB
    override func prepareForInterfaceBuilder() {
        super.prepareForInterfaceBuilder()
        self.setupViews()
    }
}