22.手势识别之UIPinchGestureRecognizer

UIPinchGestureRecognizer

1. UIPinchGestureRecognizer的创建

import UIKit

class ViewController: UIViewController {

var label: UILabel!

override func viewDidLoad() {
super.viewDidLoad()

label = UILabel(frame: CGRect(x: 20, y: 20, width: 300, height: 60))
label?.textAlignment = .Center
self.view.addSubview(label!)

let pinch = UIPinchGestureRecognizer(target: self, action: "pinchAction:")
self.view.addGestureRecognizer(pinch)
}

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

func pinchAction(pinchGestureRecognizer: UIPinchGestureRecognizer) {
self.label.text = "scale:\(pinchGestureRecognizer.scale)"
}

}

2. UIPinchGestureRecognizer详解

@available(iOS 3.2, *)
public class UIPinchGestureRecognizer : UIGestureRecognizer {

// 缩放比例
public var scale: CGFloat
// 缩放速度
public var velocity: CGFloat { get }
}

3. 完整代码