如何快速创建 UnsafeMutablePointer<CGPoint> 对象答案

【问题标题】：How to create UnsafeMutablePointer<CGPoint> Object in swift如何快速创建 UnsafeMutablePointer<CGPoint> 对象
【发布时间】：2016-05-20 11:03:25
【问题描述】：

我需要调用UIScrollViewDelegate方法我不知道如何创建UnsafeMutablePointer对象。

let pointer:UnsafeMutablePointer<CGPoint>  = CGPoint(x: 0, y: 1) as! UnsafeMutablePointer<CGPoint>

self.scrollViewWillEndDragging(self.collectionView, withVelocity: CGPoint(x: 0, y: 1), targetContentOffset: pointer)

func scrollViewWillEndDragging(scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) 
{  
     //Some code here
}

【问题讨论】：

标签： ios xcode swift scrollview

【解决方案1】：

import Foundation
var point = CGPoint(x: 10.0, y: 20.0)
let p = withUnsafeMutablePointer(&point) { (p) -> UnsafeMutablePointer<CGPoint> in
    return p
}

print(p.memory.x, p.memory.y) // 10.0 20.0
point.x = 100.0
print(p.memory.x, p.memory.y) // 100.0 20.0

借助 Swift 的语法糖

import Foundation
var point = CGPoint(x: 10.0, y: 20.0)
let p = withUnsafeMutablePointer(&point) { $0 }

print(p.dynamicType) // UnsafeMutablePointer<CGPoint>

【讨论】：