IOS 七种手势操作
今天为大家介绍一下IOS 的七种手势，手势在开发中经常用到，所以就简单 通俗易懂的说下， 话不多说，直接看代码：
1、UIGestureRecognizer 介绍
【资料图】
手势识别在 iOS 中非常重要，他极大地提高了移动设备的使用便捷性。
iOS 系统在 3.2 以后，他提供了一些常用的手势（UIGestureRecognizer 的子类），开发者可以直接使用他们进行手势操作。
UIPanGestureRecognizer（拖动） UIPinchGestureRecognizer（捏合） UIRotationGestureRecognizer（旋转） UITapGestureRecognizer（点按） UILongPressGestureRecognizer（长按） UISwipeGestureRecognizer（轻扫）另外，可以通过继承 UIGestureRecognizer 类，实现自定义手势（手势识别器类）。
PS：自定义手势时，需要 #import <UIKit/UIGestureRecognizerSubclass.h>，一般需实现如下方法：
- (void)reset;- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event;- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event;- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event;- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event;//以上方法在分类 UIGestureRecognizer (UIGestureRecognizerProtected) 中声明，更多方法声明请自行查看
UIGestureRecognizer 的继承关系如下：
2、手势状态
在六种手势识别中，只有一种手势是离散型手势，他就是 UITapGestureRecognizer。
离散型手势的特点就是：一旦识别就无法取消，而且只会调用一次手势操作事件（初始化手势时指定的回调方法）。
换句话说其他五种手势是连续型手势，而连续型手势的特点就是：会多次调用手势操作事件，而且在连续手势识别后可以取消手势。从下图可以看出两者调用操作事件的次数是不同的：
手势状态枚举如下：
typedef NS_ENUM(NSInteger, UIGestureRecognizerState) { UIGestureRecognizerStatePossible, // 尚未识别是何种手势操作（但可能已经触发了触摸事件），默认状态 UIGestureRecognizerStateBegan, // 手势已经开始，此时已经被识别，但是这个过程中可能发生变化，手势操作尚未完成 UIGestureRecognizerStateChanged, // 手势状态发生转变 UIGestureRecognizerStateEnded, // 手势识别操作完成（此时已经松开手指） UIGestureRecognizerStateCancelled, // 手势被取消，恢复到默认状态 UIGestureRecognizerStateFailed, // 手势识别失败，恢复到默认状态 UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded // 手势识别完成，同UIGestureRecognizerStateEnded};对于离散型手势 UITapGestureRecgnizer 要么被识别，要么失败，点按（假设点按次数设置为1，并且没有添加长按手势）下去一次不松开则此时什么也不会发生，松开手指立即识别并调用操作事件，并且状态为3（已完成）。
但是连续型手势要复杂一些，就拿旋转手势来说，如果两个手指点下去不做任何操作，此时并不能识别手势（因为我们还没旋转）但是其实已经触发了触摸开始事件，此时处于状态0；如果此时旋转会被识别，也就会调用对应的操作事件，同时状态变成1（手势开始），但是状态1只有一瞬间；紧接着状态变为2（因为我们的旋转需要持续一会），并且重复调用操作事件（如果在事件中打印状态会重复打印2）；松开手指，此时状态变为3，并调用1次操作事件。
3、使用手势的步骤
使用手势很简单，分为三步：
创建手势识别器对象实例。创建时，指定一个回调方法，当手势开始，改变、或结束时，执行回调方法。 设置手势识别器对象实例的相关属性（可选部分） 添加到需要识别的 View 中。每个手势只对应一个 View，当屏幕触摸在 View 的边界内时，如果手势和预定的一样，那就会执行回调方法。PS：一个手势只能对应一个 View，但是一个 View 可以有多个手势。建议在真机上测试这些手势，模拟器操作不太方便，可能导致认为手势失效的情况。（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）
4、举例说明
功能描述：
附加到两个图片视图 UIImageView 的有『拖动』、『捏合』、『旋转』、『点按』；
而『轻扫』和『自定义手势 KMGestureRecognizer』附加在根视图 UIView 中。
拖动：进行当前图片视图位置移动
捏合：进行当前图片视图缩放
旋转：进行当前图片视图角度旋转
点按：双击恢复当前图片视图的缩放、角度旋转、不透明度
长按：设置当前图片视图的不透明度为0.7
轻扫：左右轻扫设置两个图片视图为居中，同时以垂直居中的特定偏移量定位
自定义手势：挠痒功能，左右扫动共3次或以上，设置两个图片视图为居中，同时以水平居中的特定偏移量定位
效果如下：
KMGestureRecognizer.h
#import <UIKit/UIKit.h>typedef NS_ENUM(NSUInteger, Direction) { DirectionUnknown, DirectionLeft, DirectionRight};@interface KMGestureRecognizer : UIGestureRecognizer@property (assign, nonatomic) NSUInteger tickleCount; //挠痒次数@property (assign, nonatomic) CGPoint currentTickleStart; //当前挠痒开始坐标位置@property (assign, nonatomic) Direction lastDirection; //最后一次挠痒方向@endKMGestureRecognizer.m
#import "KMGestureRecognizer.h"#import <UIKit/UIGestureRecognizerSubclass.h>@implementation KMGestureRecognizer#define kMinTickleSpacing 20.0#define kMaxTickleCount 3- (void)reset { _tickleCount = 0; _currentTickleStart = CGPointZero; _lastDirection = DirectionUnknown; if (self.state == UIGestureRecognizerStatePossible) { self.state = UIGestureRecognizerStateFailed; }}- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [touches anyObject]; _currentTickleStart = [touch locationInView:self.view]; //设置当前挠痒开始坐标位置}- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { //『当前挠痒开始坐标位置』和『移动后坐标位置』进行 X 轴值比较，得到是向左还是向右移动 UITouch *touch = [touches anyObject]; CGPoint tickleEnd = [touch locationInView:self.view]; CGFloat tickleSpacing = tickleEnd.x - _currentTickleStart.x; Direction currentDirection = tickleSpacing < 0 ? DirectionLeft : DirectionRight; //移动的 X 轴间距值是否符合要求，足够大 if (ABS(tickleSpacing) >= kMinTickleSpacing) { //判断是否有三次不同方向的动作，如果有则手势结束，将执行回调方法 if (_lastDirection == DirectionUnknown || (_lastDirection == DirectionLeft && currentDirection == DirectionRight) || (_lastDirection == DirectionRight && currentDirection == DirectionLeft)) { _tickleCount++; _currentTickleStart = tickleEnd; _lastDirection = currentDirection; if (_tickleCount >= kMaxTickleCount && self.state == UIGestureRecognizerStatePossible) { self.state = UIGestureRecognizerStateEnded; //NSLog(@"自定义手势成功，将执行回调方法"); } } }}- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { [self reset];}- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event { [self reset];}@endViewController.h
#import <UIKit/UIKit.h>#import "KMGestureRecognizer.h"@interface ViewController : UIViewController@property (strong, nonatomic) UIImageView *imgV;@property (strong, nonatomic) UIImageView *imgV2;@property (strong, nonatomic) KMGestureRecognizer *customGestureRecognizer;@end
ViewController.m
#import "ViewController.h"@interface ViewController ()- (void)handlePan:(UIPanGestureRecognizer *)recognizer;- (void)handlePinch:(UIPinchGestureRecognizer *)recognizer;- (void)handleRotation:(UIRotationGestureRecognizer *)recognizer;- (void)handleTap:(UITapGestureRecognizer *)recognizer;- (void)handleLongPress:(UILongPressGestureRecognizer *)recognizer;- (void)handleSwipe:(UISwipeGestureRecognizer *)recognizer;- (void)handleCustomGestureRecognizer:(KMGestureRecognizer *)recognizer;- (void)bindPan:(UIImageView *)imgVCustom;- (void)bindPinch:(UIImageView *)imgVCustom;- (void)bindRotation:(UIImageView *)imgVCustom;- (void)bindTap:(UIImageView *)imgVCustom;- (void)bindLongPress:(UIImageView *)imgVCustom;- (void)bindSwipe;- (void)bingCustomGestureRecognizer;- (void)layoutUI;@end@implementation ViewController- (void)viewDidLoad { [super viewDidLoad]; [self layoutUI];}- (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated.}#pragma mark - 处理手势操作/** * 处理拖动手势 * * @param recognizer 拖动手势识别器对象实例 */- (void)handlePan:(UIPanGestureRecognizer *)recognizer { //视图前置操作 [recognizer.view.superview bringSubviewToFront:recognizer.view]; CGPoint center = recognizer.view.center; CGFloat cornerRadius = recognizer.view.frame.size.width / 2; CGPoint translation = [recognizer translationInView:self.view]; //NSLog(@"%@", NSStringFromCGPoint(translation)); recognizer.view.center = CGPointMake(center.x + translation.x, center.y + translation.y); [recognizer setTranslation:CGPointZero inView:self.view]; if (recognizer.state == UIGestureRecognizerStateEnded) { //计算速度向量的长度，当他小于200时，滑行会很短 CGPoint velocity = [recognizer velocityInView:self.view]; CGFloat magnitude = sqrtf((velocity.x * velocity.x) + (velocity.y * velocity.y)); CGFloat slideMult = magnitude / 200; //NSLog(@"magnitude: %f, slideMult: %f", magnitude, slideMult); //e.g. 397.973175, slideMult: 1.989866 //基于速度和速度因素计算一个终点 float slideFactor = 0.1 * slideMult; CGPoint finalPoint = CGPointMake(center.x + (velocity.x * slideFactor), center.y + (velocity.y * slideFactor)); //限制最小［cornerRadius］和最大边界值［self.view.bounds.size.width - cornerRadius］，以免拖动出屏幕界限 finalPoint.x = MIN(MAX(finalPoint.x, cornerRadius), self.view.bounds.size.width - cornerRadius); finalPoint.y = MIN(MAX(finalPoint.y, cornerRadius), self.view.bounds.size.height - cornerRadius); //使用 UIView 动画使 view 滑行到终点 [UIView animateWithDuration:slideFactor*2 delay:0 options:UIViewAnimationOptionCurveEaseOut animations:^{ recognizer.view.center = finalPoint; } completion:nil]; }}/** * 处理捏合手势 * * @param recognizer 捏合手势识别器对象实例 */- (void)handlePinch:(UIPinchGestureRecognizer *)recognizer { CGFloat scale = recognizer.scale; recognizer.view.transform = CGAffineTransformScale(recognizer.view.transform, scale, scale); //在已缩放大小基础下进行累加变化；区别于：使用 CGAffineTransformMakeScale 方法就是在原大小基础下进行变化 recognizer.scale = 1.0;}/** * 处理旋转手势 * * @param recognizer 旋转手势识别器对象实例 */- (void)handleRotation:(UIRotationGestureRecognizer *)recognizer { recognizer.view.transform = CGAffineTransformRotate(recognizer.view.transform, recognizer.rotation); recognizer.rotation = 0.0;}/** * 处理点按手势 * * @param recognizer 点按手势识别器对象实例 */- (void)handleTap:(UITapGestureRecognizer *)recognizer { UIView *view = recognizer.view; view.transform = CGAffineTransformMakeScale(1.0, 1.0); view.transform = CGAffineTransformMakeRotation(0.0); view.alpha = 1.0;}/** * 处理长按手势 * * @param recognizer 点按手势识别器对象实例 */- (void)handleLongPress:(UILongPressGestureRecognizer *)recognizer { //长按的时候，设置不透明度为0.7 recognizer.view.alpha = 0.7;}/** * 处理轻扫手势 * * @param recognizer 轻扫手势识别器对象实例 */- (void)handleSwipe:(UISwipeGestureRecognizer *)recognizer { //代码块方式封装操作方法 void (^positionOperation)() = ^() { CGPoint newPoint = recognizer.view.center; newPoint.y -= 20.0; _imgV.center = newPoint; newPoint.y += 40.0; _imgV2.center = newPoint; }; //根据轻扫方向，进行不同控制 switch (recognizer.direction) { case UISwipeGestureRecognizerDirectionRight: { positionOperation(); break; } case UISwipeGestureRecognizerDirectionLeft: { positionOperation(); break; } case UISwipeGestureRecognizerDirectionUp: { break; } case UISwipeGestureRecognizerDirectionDown: { break; } }}/** * 处理自定义手势 * * @param recognizer 自定义手势识别器对象实例 */- (void)handleCustomGestureRecognizer:(KMGestureRecognizer *)recognizer { //代码块方式封装操作方法 void (^positionOperation)() = ^() { CGPoint newPoint = recognizer.view.center; newPoint.x -= 20.0; _imgV.center = newPoint; newPoint.x += 40.0; _imgV2.center = newPoint; }; positionOperation();}#pragma mark - 绑定手势操作/** * 绑定拖动手势 * * @param imgVCustom 绑定到图片视图对象实例 */- (void)bindPan:(UIImageView *)imgVCustom { UIPanGestureRecognizer *recognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)]; [imgVCustom addGestureRecognizer:recognizer];}/** * 绑定捏合手势 * * @param imgVCustom 绑定到图片视图对象实例 */- (void)bindPinch:(UIImageView *)imgVCustom { UIPinchGestureRecognizer *recognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(handlePinch:)]; [imgVCustom addGestureRecognizer:recognizer]; //[recognizer requireGestureRecognizerToFail:imgVCustom.gestureRecognizers.firstObject];}/** * 绑定旋转手势 * * @param imgVCustom 绑定到图片视图对象实例 */- (void)bindRotation:(UIImageView *)imgVCustom { UIRotationGestureRecognizer *recognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(handleRotation:)]; [imgVCustom addGestureRecognizer:recognizer];}/** * 绑定点按手势 * * @param imgVCustom 绑定到图片视图对象实例 */- (void)bindTap:(UIImageView *)imgVCustom { UITapGestureRecognizer *recognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTap:)]; //使用一根手指双击时，才触发点按手势识别器 recognizer.numberOfTapsRequired = 2; recognizer.numberOfTouchesRequired = 1; [imgVCustom addGestureRecognizer:recognizer];}/** * 绑定长按手势 * * @param imgVCustom 绑定到图片视图对象实例 */- (void)bindLongPress:(UIImageView *)imgVCustom { UILongPressGestureRecognizer *recognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPress:)]; recognizer.minimumPressDuration = 0.5; //设置最小长按时间；默认为0.5秒 [imgVCustom addGestureRecognizer:recognizer];}/** * 绑定轻扫手势；支持四个方向的轻扫，但是不同的方向要分别定义轻扫手势 */- (void)bindSwipe { //向右轻扫手势 UISwipeGestureRecognizer *recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipe:)]; recognizer.direction = UISwipeGestureRecognizerDirectionRight; //设置轻扫方向；默认是 UISwipeGestureRecognizerDirectionRight，即向右轻扫 [self.view addGestureRecognizer:recognizer]; [recognizer requireGestureRecognizerToFail:_customGestureRecognizer]; //设置以自定义挠痒手势优先识别 //向左轻扫手势 recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipe:)]; recognizer.direction = UISwipeGestureRecognizerDirectionLeft; [self.view addGestureRecognizer:recognizer]; [recognizer requireGestureRecognizerToFail:_customGestureRecognizer]; //设置以自定义挠痒手势优先识别}/** * 绑定自定义挠痒手势；判断是否有三次不同方向的动作，如果有则手势结束，将执行回调方法 */- (void)bingCustomGestureRecognizer { //当 recognizer.state 为 UIGestureRecognizerStateEnded 时，才执行回调方法 handleCustomGestureRecognizer: //_customGestureRecognizer = [KMGestureRecognizer new]; _customGestureRecognizer = [[KMGestureRecognizer alloc] initWithTarget:self action:@selector(handleCustomGestureRecognizer:)]; [self.view addGestureRecognizer:_customGestureRecognizer];}- (void)layoutUI { //图片视图 _imgV UIImage *img = [UIImage imageNamed:@"Emoticon_tusiji_icon"]; CGFloat cornerRadius = img.size.width; _imgV = [[UIImageView alloc] initWithImage:img]; _imgV.frame = CGRectMake(20.0, 20.0, cornerRadius * 2, cornerRadius * 2); _imgV.userInteractionEnabled = YES; _imgV.layer.masksToBounds = YES; _imgV.layer.cornerRadius = cornerRadius; _imgV.layer.borderWidth = 2.0; _imgV.layer.borderColor = [UIColor grayColor].CGColor; [self.view addSubview:_imgV]; //图片视图 _imgV2 img = [UIImage imageNamed:@"Emoticon_tusiji_icon2"]; cornerRadius = img.size.width; _imgV2 = [[UIImageView alloc] initWithImage:img]; _imgV2.frame = CGRectMake(20.0, 40.0 + _imgV.frame.size.height, cornerRadius * 2, cornerRadius * 2); _imgV2.userInteractionEnabled = YES; _imgV2.layer.masksToBounds = YES; _imgV2.layer.cornerRadius = cornerRadius; _imgV2.layer.borderWidth = 2.0; _imgV2.layer.borderColor = [UIColor orangeColor].CGColor; [self.view addSubview:_imgV2]; [self bindPan:_imgV]; [self bindPinch:_imgV]; [self bindRotation:_imgV]; [self bindTap:_imgV]; [self bindLongPress:_imgV]; [self bindPan:_imgV2]; [self bindPinch:_imgV2]; [self bindRotation:_imgV2]; [self bindTap:_imgV2]; [self bindLongPress:_imgV2]; //为了处理手势识别优先级的问题，这里需先绑定自定义挠痒手势 [self bingCustomGestureRecognizer]; [self bindSwipe];}@end
