1.創(chuàng)建一個(gè)swift文件

h1 命名可以按照OC的習(xí)慣命名,例如UIView+Extension

圖例1png

2.分類實(shí)現(xiàn),如下UIView的分類寫法書(shū)寫

import Foundation
import UIKit

extension UIView
{
    public var x:CGFloat
        {
        get{
            return self.frame.origin.x
        }
        
        set{
            var frame = self.frame
            frame.origin.x = x
            self.frame = frame
        }
    }
    
    public var y:CGFloat
        {
        get{
            return self.frame.origin.y
        }
        set{
            var frame = self.frame
            frame.origin.y = y
            self.frame = frame
        }
    }
    
    public var width:CGFloat
        {
        get{
            return self.frame.size.width
        }
        set{
            var frame = self.frame
            frame.size.width = width
            self.frame = frame
        }
    }
    
    public var height:CGFloat
        {
        get{
            return self.frame.size.height
        }
        set{
            var frame = self.frame
            frame.size.height = height
            self.frame = frame
        }
    }
    
    public var centerX:CGFloat
        {
        get{
            return self.center.x
        }
        set{
            var center = self.center
            center.x = centerX
            self.center = center
        }
    }
    
    public var centerY :CGFloat
        {
        get{
            return self.center.y
        }
        set{
            var center = self.center
            center.y = centerY
            self.center = center
        }
    }
    
    public var size:CGSize
        {
        get{
            return self.frame.size
        }
        set{
            var tempFrame = self.frame
            tempFrame.size = size
            self.frame = tempFrame
        }
    }
}