24.手势识别之UIPanGestureRecognizer

UIPanGestureRecognizer

1. UIPanGestureRecognizer的创建

import UIKit

class ViewController: UIViewController {

var imageView: UIImageView!

override func viewDidLoad() {
super.viewDidLoad()

self.imageView = UIImageView(image: UIImage(named: "beautiful"))
self.imageView.center = self.view.center
self.view.addSubview(imageView)

let panGestureRecognizer = UIPanGestureRecognizer(target: self, action: "panAction:")
self.view.addGestureRecognizer(panGestureRecognizer)
}

override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}

func panAction(panGestureRecognizer: UIPanGestureRecognizer) {
// 获取触摸点在当前view中的位置
let pos = panGestureRecognizer.locationInView(self.view)
self.imageView.center = pos
}

}

2. UIPanGestureRecognizer详解

@available(iOS 3.2, *)
public class UIPanGestureRecognizer : UIGestureRecognizer {
// 最少触摸手指数, 默认是1
public var minimumNumberOfTouches: Int
// 最多触摸手指数, 默认是UINT_MAX
public var maximumNumberOfTouches: Int

// 获取屏幕坐标系转为指定view的自身坐标系后的坐标
public func translationInView(view: UIView?) -> CGPoint
public func setTranslation(translation: CGPoint, inView view: UIView?)

// 在指定的view中坐标系统中的拖动速度
public func velocityInView(view: UIView?) -> CGPoint
}

public func locationInView(view: UIView?) -> CGPoint

3. 完整代码