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
}
解决方法
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
借助斯威夫特的句法糖
import Foundation
var point = CGPoint(x: 10.0,y: 20.0)
let p = withUnsafeMutablePointer(&point) { $0 }
print(p.dynamicType) // UnsafeMutablePointer<CGPoint>