Swift - 手势UIGestureRecognizer及其子

2018-01-19 本文已影响0人解码漫聊

UIGestureRecognizer 有许多子类，用于监听一些常见的手势事件，这些子类主要有：

1.UISwipeGestureRecognizer：滑动（快速移动）

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        //滑动手势
        let swipe = UISwipeGestureRecognizer(target: self, action: #selector(swipe(recognizer:)))
        swipe.direction = .up
        self.view.addGestureRecognizer(swipe)
        
    }

    @objc func swipe(recognizer:UISwipeGestureRecognizer) {
        print("swipe swipe")
        let point = recognizer.location(in: view)
        print("滑动起点坐标（x:\(point.x), y:\(point.y)）")
    }
}

打印结果：

swipe swipe
滑动起点坐标（x:196.0, y:336.666656494141）

注意1：如果 UISwipeGestureRecognizer 在不指定方向的时候，默认向右滑动才会触发事件。如果要指定方向，需要设置 direction 属性:

//表示监听滑动的方向为向上
swipe.direction = .up

如果希望各个方向都响应手势，定义不同方向的UISwipeGestureRecognizer，添加到被监听对象：

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        //向上滑动手势
        let swipeUp = UISwipeGestureRecognizer(target: self, action: #selector(swipe(recognizer:)))
        swipeUp.direction = .up
        self.view.addGestureRecognizer(swipeUp)
        
        //向下滑动手势
        let swipeDown = UISwipeGestureRecognizer(target: self, action: #selector(swipe(recognizer:)))
        swipeDown.direction = .down
        view.addGestureRecognizer(swipeDown)
    }

    @objc func swipe(recognizer:UISwipeGestureRecognizer) {
        if recognizer.direction == .up {
            print("这是向上滑动")
        } else if recognizer.direction == .down {
            print("这是向下滑动")
        }
        let point = recognizer.location(in: view)
        print("滑动起点坐标（x:\(point.x), y:\(point.y)）")
    }
}

打印结果：

这是向下滑动
滑动起点坐标（x:192.0, y:271.666656494141）
这是向上滑动
滑动起点坐标（x:212.33332824707, y:454.33332824707）

2.UIScreenEdgePanGestureRecognizer：边缘滑动

这个是 UISwipeGestureRecognizer 的子类，与后者不同的时。UIScreenEdgePanGestureRecognizer 只触发从边缘开始的划动操作，比如从左侧边缘开始向右滑动。
UIScreenEdgePanGestureRecognizer 没有 direction 属性，增加了个 edges 属性。表示要响应哪个边缘的划动操作。可以是从左边缘向右滑动，或右边缘向左、上边缘向下、下边缘向上、或响应全部边缘滑动。

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        let edgeSwipe = UIScreenEdgePanGestureRecognizer(target: self, action: #selector(edgeSwipe(recognizer:)))
        //从右边缘开始滑动
        edgeSwipe.edges = .right
        view.addGestureRecognizer(edgeSwipe)
        
    }

    @objc func edgeSwipe(recognizer:UIScreenEdgePanGestureRecognizer) {
        if recognizer.edges == .right {
            print("这是从右边开始滑动")
        }
        let point = recognizer.location(in: view)
        print("滑动起点坐标（x:\(point.x), y:\(point.y)）")
    }
}

3.UITapGestureRecognizer：轻点手势（点击）

可以通过 numberOfTouchesRequired 属性设置触摸点数，比如设置 2 表示必须两个手指触摸时才会触发
通过 numberOfTapsRequired 属性设置点击次数，单击设置为 1，双击设置为 2
如果一个控件既监听了单击事件也监听了双击事件，默认当双击事件触发的时候也同时会触发单击事件。如果想双击时不触发单击，需要通过 require(toFail:) 进行设置

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
    
        //单击
        let singleTap = UITapGestureRecognizer(target: self, action: #selector(singleTap(recognizer:)))
        singleTap.numberOfTapsRequired = 1
        singleTap.numberOfTouchesRequired = 1
        
        //双击
        let doubleTap = UITapGestureRecognizer(target: self, action: #selector(doubleTap(recognizer:)))
        doubleTap.numberOfTapsRequired = 2
        doubleTap.numberOfTouchesRequired = 1
        
        //声明单击事件需要双击事件检测失败后才会执行
        singleTap.require(toFail: doubleTap)
        
        view.addGestureRecognizer(singleTap)
        view.addGestureRecognizer(doubleTap)
        
    }

    @objc func singleTap(recognizer:UITapGestureRecognizer) {
        print("这是单击")
    }
    
    @objc func doubleTap(recognizer:UITapGestureRecognizer) {
        print("这是双击")
    }
}

4.UIPinchGestureRecognizer：捏合手势（两个手指进行放大缩小）

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
    
        let pinch = UIPinchGestureRecognizer(target: self, action: #selector(pinch(recognizer:)))
        
        view.addGestureRecognizer(pinch)
    }

    @objc func pinch(recognizer:UIPinchGestureRecognizer) {
        //实时获取捏合的比例
        print("捏合比例:\(recognizer.scale)")
        
        //获取两个触摸点的坐标
        print(recognizer.location(ofTouch: 0, in: view))
        print(recognizer.location(ofTouch: 1, in: view))
    }
}

注意：模拟器测试捏合和旋转手势时，按住 option 键，再用触摸板或鼠标操作

5.UIRotationGestureRecognizer：旋转手势（两个手指进行旋转）

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let rotation = UIRotationGestureRecognizer(target: self, action:
            #selector(rotation(recognizer:)))
        
        view.addGestureRecognizer(rotation)
    }

    @objc func rotation(recognizer:UIRotationGestureRecognizer) {
        //旋转的弧度转换为角度
        print(recognizer.rotation*(180/CGFloat.pi))

    }
}

6.UIPanGestureRecognizer：拖动手势

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let redView = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
        redView.backgroundColor = UIColor.red
        redView.center = view.center
        view.addSubview(redView)
        
        let pan = UIPanGestureRecognizer(target: self, action:
            #selector(pan(recognizer:)))
        
        redView.addGestureRecognizer(pan)
    }

    @objc func pan(recognizer:UIRotationGestureRecognizer) {
        
        let point = recognizer.location(in: view)
        //设置矩形的位置
        recognizer.view?.center = point
        
    }
}

注意

通过 recognizer.view 我们可以直接得到触发事件的 view 对象
一个 GestureRecognizer 只能对应一个 view，所以每个 view 还是要分别使用各自的 GestureRecognizer

实例：

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let redView = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
        redView.backgroundColor = UIColor.red
        redView.center = view.center
        view.addSubview(redView)
        
        let yellowView = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
        yellowView.backgroundColor = UIColor.yellow
        view.addSubview(yellowView)
        
        
        let pan1 = UIPanGestureRecognizer(target: self, action:
            #selector(pan(recognizer:)))
        redView.addGestureRecognizer(pan1)
        
        let pan2 = UIPanGestureRecognizer(target: self, action:
            #selector(pan(recognizer:)))
        yellowView.addGestureRecognizer(pan2)
    }

    @objc func pan(recognizer:UIRotationGestureRecognizer) {
        
        let point = recognizer.location(in: view)
        //设置矩形的位置
        recognizer.view?.center = point
        
    }
}

7.UILongPressGestureRecognizer：长按

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let longPress = UILongPressGestureRecognizer(target: self, action:
            #selector(longPress(recognizer:)))
        view.addGestureRecognizer(longPress)
    }

    @objc func longPress(recognizer:UIRotationGestureRecognizer) {
        if recognizer.state == .began {
            print("长按响应开始")
        } else {
            print("长按响应结束")
        }
    }
}