IOS 七种手势操作（拖动、捏合、旋转、点按、长

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

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。

1. UIPanGestureRecognizer（拖动）
2. UIPinchGestureRecognizer（捏合）
3. UIRotationGestureRecognizer（旋转）
4. UITapGestureRecognizer（点按）
5. UILongPressGestureRecognizer（长按）
6. ​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：

1. 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。
2. 设置手势识别器对象实例的相关属性（可选部分）
3. 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

@end

KMGestureRecognizer.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];
}

@end

ViewController.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

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