[Objective-C] 纯文本查看 复制代码
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
let loc = (touches as NSSet).anyObject()?.locationInView(self.superview)
let oldP = (touches as NSSet).anyObject()?.previousLocationInView(self.superview)
let deltaX = (loc?.x)! - (oldP?.x)!
let deltaY = (loc?.y)! - (oldP?.y)!
var c = self.center
c.x += deltaX
c.y += deltaY
self.center = c
}[Objective-C] 纯文本查看 复制代码
//定义两个属性，存储识别时的状态
var decided = false //是否确定移动方向了
var horiz = false //是否水平移动
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
decided = false
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
if !decided { //第一次调用， 确定移动的方向。
decided = true
let then = (touches as NSSet).anyObject()?.previousLocationInView(self.superview)
let now = (touches as NSSet).anyObject()?.locationInView(self.superview)
let deltaX = fabs((now?.x)! - (then?.x)!)
let deltaY = fabs((now?.y)! - (then?.y)!)
horiz = deltaX>=deltaY
}
let loc = (touches as NSSet).anyObject()?.locationInView(self.superview)
let oldP = (touches as NSSet).anyObject()?.previousLocationInView(self.superview)
let deltaX = (loc?.x)! - (oldP?.x)!
let deltaY = (loc?.y)! - (oldP?.y)!
var c = self.center
if horiz{
c.x += deltaX
}else{
c.y += deltaY
}
self.center = c
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
}
[Objective-C] 纯文本查看 复制代码
var time:Double = 0 //记录时间开始时的时间
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
time = (touches.first?.timestamp)!
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
let diff = (touches.first?.timestamp)! - time //计算间隔
if diff > 0.5{
print("long")
}else{
print("short")
}
}
[Objective-C] 纯文本查看 复制代码
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) { time = (touches.first?.timestamp)!
performSelector("longPress", withObject: nil, afterDelay: 0.5) //延迟执行
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
let diff = (touches.first?.timestamp)! - time
//当时间间隔<=0.5时，判断为短按。另外还要取消 performSelector...指定的延迟消息。 不然longPress()总会调用
if diff <= 0.5{
print("short")
NSObject.cancelPreviousPerformRequestsWithTarget(self, selector: "longPress", object: nil)
}
}
func longPress(){
print("longPress")
}上面判断长按和短按的方法也可以应用在 单击和双击。虽然 UITouch的tapCount属性可以实现这个目标，但是并不能对单击，双击做出不同的响应。
[Objective-C] 纯文本查看 复制代码
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
let ct = touches.first!.tapCount
if(ct==2){ //取消点击一次的延时执行函数
NSObject.cancelPreviousPerformRequestsWithTarget(self, selector: "singTap", object: nil)
}
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
let ct = touches.first!.tapCount
if ct==1{// 点第一下0.3秒后 不点击第二下， 就会执行singTap()
self.performSelector("singTap", withObject: nil, afterDelay: 0.3)
}
if ct==2{
print("doubleTap")
}
}
func singTap(){
print("singTap")
}现在可以实现： 长按，单击，双击，拖动，在水平, 垂直方向移动。 每种模式的代码有些不好理解了。 那么将上面这些代码组和起来，使view可以同时进行 长按，单击，双击，拖动，在水平, 垂直方向移动。。。。这是相当可怕的。写出来的代码完全不具备可读性，还有难以理解的逻辑。这就是发明手势识别器的原因之一。
3，手势识别器3.1 手势识别器类的介绍- UIGestureRecognizer ： 手势识别器抽象类
[Objective-C] 纯文本查看 复制代码
// 系统提供的手势识别器都是继承 UIGestureRecognizer类。
- initWithTarget:action: //初始化方法，识别到手势后发送消息action到target
- addTarget:action: //添加 target-action
- removeTarget:action: //移除 target-action
- locationInView: //触摸点在指定view上的坐标。如果是单点触摸，就是这个点；如果是多点触摸，是这几个点的中点。（重心）
- numberOfTouches //识别到的手势对象中包含 UITouch对象的个数
- locationOfTouch:inView: //指定touch在指定view上的坐标。touch通过index指定。
- requireGestureRecognizerToFail: //只有当指定的识别器识别失败，自己才去识别
state //当前的状态
delegate //代理
enabled //关闭手势识别器
view //手势识别器所从属的view
cancelsTouchesInView // 默认为YES,这种情况下当手势识别器识别到touch之后，会发送touchesCancelled给hit-testview以取消hit-test view对touch的响应，这个时候只有手势识别器响应touch。当设置成NO时，手势识别器识别到touch之后不会发送touchesCancelled给hit-test，这个时候手势识别器和hit-test view均响应touch。
delaysTouchesBegan //默认是NO，这种情况下当发生一个touch时，手势识别器先捕捉到到touch，然后发给hit-testview，两者各自做出响应。如果设置为YES，手势识别器在识别的过程中（注意是识别过程），不会将touch发给hit-test view，即hit-testview不会有任何触摸事件。只有在识别失败之后才会将touch发给hit-testview，这种情况下hit-test view的响应会延迟约0.15ms。
delaysTouchesEnded //默认为YES。这种情况下发生一个touch时，在手势识别成功后,发送给touchesCancelled消息给hit-testview，手势识别失败时，会延迟大概0.15ms,期间没有接收到别的touch才会发送touchesEnded。如果设置为NO，则不会延迟，即会立即发送touchesEnded以结束当前触摸。
numberOfTapsRequired //点击次数
numberOfTouchesRequired //触摸点数
scale //缩放比例
velocity //缩放速度- UIRotationGestureRecognizer
rotation //旋转角度
velocity //缩放速度direction //允许的方向
numberOfTouchesRequired //触摸点数maximumNumberOfTouches //最多触摸点数
minimumNumberOfTouches //最少触摸点数- UILongPressGestureRecognizer
minimumPressDuration //手势识别的最小时长
numberOfTouchesRequirednumberOfTapsRequiredallowableMovement //补偿用户手指在长期按压无法保持平稳的事实。eg:确认长按后可以进行拖动。
3.2 status
识别器状态
识别器可以分为两类： 离散的， 连续的。状态之间的转换上图中很明了。
3.3 多重手势识别器一个视图上面可以添加多个手势识别器。同时当触摸一个视图时，不仅本视图的识别器在进行识别操作，视图层次结构中的父视图中的识别器也在工作。所以可以认为一个视图被很多手势识别器包围。
在这些手势识别器中， 一旦一个识别器识别到了它的手势，任何和它的触摸关联的其他手势识别器强制设置为失败状态。
有时这不是我们想要的，比如 识别单击和双击。
[Objective-C] 纯文本查看 复制代码
override init(frame: CGRect) {
super.init(frame: frame)
self.backgroundColor = UIColor.blueColor()
let t2 = UITapGestureRecognizer(target: self, action: "doubleTap")
t2.numberOfTapsRequired = 2
addGestureRecognizer(t2)
let t1 = UITapGestureRecognizer(target: self, action: "singleTap")
t1.requireGestureRecognizerToFail(t2) //只有t2识别失败后,t1才进行识别操作
addGestureRecognizer(t1)
}
func doubleTap(){
print("doubleTap")
}
func singleTap(){
print("singleTap")
}
4 继承手势识别器继承手势识别器，就是重写touches,和相关方法。 在方法中改变手势状态信息和一些属性信息。
一般都会调用父类的touches方法，毕竟父类的touches中做了大量的计算识别工作。 下面通过一个只能识别水平移动的手势来举例：
[Objective-C] 纯文本查看 复制代码
//
// HerizonalPanGestureRecognizer.swift
// GestureRecognizerDemo
//
// Created by 贺俊孟 on 16/5/13.
// Copyright © 2016年 贺俊孟. All rights reserved.
// 只能够水平拖动
import UIKit
import UIKit.UIGestureRecognizerSubclass //这个extension可以使手势可以继承。否则你没法重写必要的方法。
class HerizonalPanGestureRecognizer: UIPanGestureRecognizer {
var origLoc:CGPoint! //记录开始时的坐标
override init(target: AnyObject?, action: Selector) {
super.init(target: target, action: action)
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent) {
origLoc = touches.first?.locationInView(view?.superview)
super.touchesBegan(touches, withEvent: event)
}
//所有的识别逻辑都是在这里进行。第一次调用时状态是 Possible
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent) {
if self.state == .Possible{
let loc:CGPoint! = touches.first?.locationInView(view?.superview)
let deltaX = fabs(loc.x-origLoc.x)
let deltaY = fabs(loc.y - origLoc.y)
//开始识别时， 如果竖直移动距离>水平移动距离，直接Failed
if deltaX <= deltaY{
state = .Failed
}
}
super.touchesMoved(touches, withEvent: event)
}
//通过重写。现在只有x 产生偏移。
override func translationInView(view: UIView?) -> CGPoint {
var proposedTranslation = super.translationInView(view)
proposedTranslation.y = 0
return proposedTranslation
}
}
// 使用
import UIKit
class BlueView: UIView {
override init(frame: CGRect) {
super.init(frame: frame)
self.backgroundColor = UIColor.blueColor()
//添加水平手势识别器
let herizonalPan = HerizonalPanGestureRecognizer(target: self, action: "herizonalPan:")
addGestureRecognizer(herizonalPan)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
// 进行水平移动
func herizonalPan(hp:HerizonalPanGestureRecognizer){
if hp.state == .Began || hp.state == .Changed{
let delta = hp.translationInView(superview)
var c = center
c.x += delta.x
c.y += delta.y
center = c
hp.setTranslation(CGPoint.zero, inView: superview) //将移动的值清零
}
}
}
5 手势识别器委托
[Objective-C] 纯文本查看 复制代码
1， gestureRecognizerShouldBegin(gestureRecognizer: UIGestureRecognizer) -> Bool //在手势识别器超越Possible状态前发送给委托。返回No,强制识别器进入Failed状态。
2,gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWithGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool //当一个手势识别器打算声明他识别的手势时，如果这个手势会强制使另一个手势识别器失败，失败的手势识别器会发送这个消息给他的代理。 返回yes,阻止这个失败。这时两个识别器同时工作。
3, gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldReceiveTouch touch: UITouch) -> Bool //在手势识别器开始touchesBegan:withEvent:之前调用。 返回false,忽略这个手势。
4，gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRequireFailureOfGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool //协调两个同时发生的手势识别
5，gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldBeRequiredToFailByGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool //识别两个同时发生的手势识别。
下面举个例子： 使用委托消息来组合 UILongPressGestureRecognizer和UIPanGestureRecognizer. 通过长按使一个view抖动， 只有在抖动的过程中才可以拖动该view。
[Objective-C] 纯文本查看 复制代码
//
// BlueView.swift
// GestureRecognizerDemo
//
// Created by 贺俊孟 on 16/5/12.
// Copyright © 2016年 贺俊孟. All rights reserved.
//
import UIKit
class BlueView: UIView {
var longP:UILongPressGestureRecognizer!
override init(frame: CGRect) {
super.init(frame: frame)
self.backgroundColor = UIColor.blueColor()
//拖动
let pan = UIPanGestureRecognizer(target: self, action: "panning:")
pan.delegate = self
addGestureRecognizer(pan)
//长按
longP = UILongPressGestureRecognizer(target: self, action: "longPress:")
longP.delegate = self
addGestureRecognizer(longP)
}
func longPress(lp:UILongPressGestureRecognizer){
if lp.state == .Began{ //开始动画
let anim = CABasicAnimation(keyPath: "transform")
anim.toValue = NSValue(CATransform3D: CATransform3DMakeScale(1.1, 1.1, 1.1))
anim.fromValue = NSValue(CATransform3D:CATransform3DIdentity)
anim.repeatCount = HUGE
anim.autoreverses = true
lp.view?.layer.addAnimation(anim, forKey: nil)
return
}
if lp.state == .Ended || lp.state == .Cancelled{ //结束动画
lp.view?.layer.removeAllAnimations()
}
}
func panning(p:UIPanGestureRecognizer){
if p.state == .Began || p.state == .Changed{
let delta = p.translationInView(superview)
var c = center
c.x += delta.x
c.y += delta.y
center = c
p.setTranslation(CGPoint.zero, inView: superview) //将移动的值清零
}
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
extension BlueView:UIGestureRecognizerDelegate{
//长按和拖动可以同时进行
func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWithGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}
//只有在长按状态时，才可以进行拖拽
override func gestureRecognizerShouldBegin(gestureRecognizer: UIGestureRecognizer) -> Bool {
if gestureRecognizer == longP{
return true
}else{
if longP.state == .Possible || longP.state == .Failed{
return false
}
return true
}
}
}
上面的代码仅仅是为了说明代理如何使用。要实现上面的效果， 只使用UILongPressGestureRecognizer就够了：
[Objective-C] 纯文本查看 复制代码
//长按
let longP = UILongPressGestureRecognizer(target: self, action: "longPress:")
addGestureRecognizer(longP)
func longPress(lp:UILongPressGestureRecognizer){
//开始动画
if lp.state == .Began{
let anim = CABasicAnimation(keyPath: "transform")
anim.toValue = NSValue(CATransform3D: CATransform3DMakeScale(1.1, 1.1, 1.1))
anim.fromValue = NSValue(CATransform3D:CATransform3DIdentity)
anim.repeatCount = HUGE
anim.autoreverses = true
lp.view?.layer.addAnimation(anim, forKey: nil)
//获取触摸点相对于center的偏移
origOffset = CGPointMake(CGRectGetMidX(bounds)-lp.locationInView(self).x, CGRectGetMidY(bounds)-lp.locationInView(self).y)
}
//进行移动
if lp.state == .Changed{
var c = lp.locationInView(superview)
c.x += origOffset.x
c.y += origOffset.y
center = c
}
//结束动画
if lp.state == .Ended || lp.state == .Cancelled{
lp.view?.layer.removeAllAnimations()
}
}
Demo在这里
上面的抖动动画使用了 Core Animation. 内容挺多的，这里就不说了。
提供一下学习资料：
CALayer
官方文档
OK ,关于手势识别，就说这么多。 这里只是抛砖引玉，为定制更加复杂的识别说一下思路。如果哪里存在问题，欢迎提出。
精华推荐:
| 欢迎光临 黑马程序员技术交流社区 (http://bbs.itheima.com/) |
黑马程序员IT技术论坛 X3.2 |
