手势识别UIGestureRecognizer

手势识别 UIGestureRecognizer

• 利用UIGestureRecognizer，能轻松识别用户在某个view上面做的一些常见手势
• UIGestureRecognizer是一个抽象类，定义了所有手势的基本行为，，使用它的子类才能处理具体手势
• 手势分类
  • UITapGestureRecognizer(点按)
  • UIPinchGestureRecognizer(捏合)
  • UIPanGestureRecognizer(拖动)
  • UISwipeGestureRecognizer(轻扫)
  • UIRotationGestureRecognizer(旋转)
  • UILongPressGestureRecognizer(长按)

/**
 手势识别，是单独添加到某一个视图上的
 ===================================
 如果要同时支持多个手势识别，需要设置手势识别代理
 - (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
 {
        return YES;
 }
 ====================================
 UIPanGestureRecognizer         拖动手势
 UIPinchGestureRecognizer       缩放手势
 UIRotationGestureRecognizer    旋转手势
 都是通过transform设置视图的形变
 一定要记住设置完transform之后，需要将对应的形变参数复位
 =====================================
 因为轻扫手势要求用户比较放松的扫动，因此最好不要将此手势添加到某一个视图上，会局限用户的操作
 ->一般要添加到self.view上
 ->如果要监听多个轻扫方向，需要添加多个轻扫手势
 =====================================
 长按手势一定要判断状态，否则方法会在手势开始和结束的时候分别调用，方法会被调用两次
 */
#import "ViewController.h"

@interface ViewController ()
@property (nonatomic, strong) UIImageView *imageView;
@end

@implementation ViewController
- (UIImageView *)imageView
{
    if(_imageView == nil){
        _imageView = [[UIImageView alloc] initWithFrame:CGRectMake(100, 100, 200, 400)];
        _imageView.image = [UIImage imageNamed:@"头像1"];
        //默认不支持点击的
        _imageView.userInteractionEnabled = YES;
        [self.view addSubview:_imageView];
    }
    return  _imageView;
}
- (void)viewDidLoad {
    [super viewDidLoad];
    [self imageView];
    [self addLongPressGesture];
}

#pragma mark - 点按手势（单击，点击）
- (void)addTapGesture
{
    UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tap)];
    //设置手势识别器对象的具体属性
    // 连续敲击2次
    tapGesture.numberOfTapsRequired = 2;
    // 需要2根手指一起敲击
    tapGesture.numberOfTouchesRequired = 2;

    [self.imageView addGestureRecognizer:tapGesture];
}
- (void)tap
{
    NSLog(@"摸我了");
}

#pragma mark - 旋转
- (void)addRotateGesture
{
    UIRotationGestureRecognizer *rotate = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotate:)];
    //设置代理，想同时执行多个手势
    rotate.delegate = self;
    [self.imageView addGestureRecognizer:rotate];
}
- (void)rotate:(UIRotationGestureRecognizer *)recognizer
{
    //recognizer.view       手势作用的视图
    //recognizer.rotation   手势的旋转
    //累加旋转之后，一定要将手势识别的旋转角度复位
    recognizer.view.transform = CGAffineTransformRotate(recognizer.view.transform, recognizer.rotation);
    // 将手势识别中的旋转角度复位
    recognizer.rotation = 0.0;          // 非常重要！
}

#pragma mark - 缩放-捏合
- (void)addPinchGesture
{
    UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinch:)];
    //设置代理，想同时执行多个手势的时候
    pinch.delegate = self;
    [self.imageView addGestureRecognizer:pinch];
}
- (void)pinch:(UIPinchGestureRecognizer *)recognizer
{
    recognizer.view.transform = CGAffineTransformScale(recognizer.view.transform, recognizer.scale, recognizer.scale);
    //将缩放比例复位
    recognizer.scale = 1.0;
}

#pragma mark - 拖动手势
- (void)addPanGesture
{
    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)];
    [self.imageView addGestureRecognizer:pan];
}
- (void)pan:(UIPanGestureRecognizer *)recognizer
{
    CGPoint translation = [recognizer translationInView:self.imageView];
    recognizer.view.transform = CGAffineTransformTranslate(recognizer.view.transform, translation.x, translation.y);
    //给平移复位
    [recognizer setTranslation:CGPointZero inView:self.imageView];
}

#pragma mark - 轻扫手势
- (void)addSwipeGesture
{
    //如果要监听多个轻扫方向，需要提那家多个轻扫手势
    //轻扫手势默认支持向右的扫动方向
    UISwipeGestureRecognizer *swipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipe:)];
    //向左扫
    UISwipeGestureRecognizer *swipeLeft =[[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipe:)];
    swipeLeft.direction = UISwipeGestureRecognizerDirectionLeft;
    //因为轻扫手势要求用户比较放松的扫动，因此最好不要将此手势添加到某一个视图上，会局限用户的操作
    [self.view addGestureRecognizer:swipe];
    [self.view addGestureRecognizer:swipeLeft];
}
- (void)swipe:(UISwipeGestureRecognizer *)recognizer
{
    CGPoint from = self.imageView.center;
    CGPoint to;
    if(recognizer.direction == UISwipeGestureRecognizerDirectionLeft){
        to = CGPointMake(-from.x, from.y);
    }else{
        to = CGPointMake(3 * from.x, from.y);
    }

    [UIView animateWithDuration:0.25 animations:^{
        self.imageView.center = to;
    } completion:^(BOOL finished) {
        [UIView animateWithDuration:0.25 animations:^{
            self.imageView.center = from;
        }];
    }];
}

#pragma mark - 长按手势
- (void)addLongPressGesture
{
    UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPress:)];
    [self.imageView addGestureRecognizer:longPress];
}
- (void)longPress:(UILongPressGestureRecognizer *)recognizer
{
    //判断手势状态，长按手势一定要判断状态，否则方法会在手势开始和结束时分别调用！方法会被调用两次
    if(recognizer.state == UIGestureRecognizerStateBegan){
        [UIView animateWithDuration:0.25 animations:^{
            self.imageView.alpha = 0.25;
        } completion:^(BOOL finished) {
            self.imageView.alpha = 1.0;
        }];
    }
}
#pragma mark - 手势识别代理方法
//同时识别两个手势
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
    return YES;
}

// 是否允许开始触发手势
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
    return YES;
}

// 是否允许接收手指的触摸点
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch{
    // 获取当前的触摸点
    CGPoint curP = [touch locationInView:self.imageView];
    if (curP.x < self.imageView.bounds.size.width * 0.5) {
        return NO;
    }else{
        return YES;
    }
}

@end


//手势识别状态
typedef NS_ENUM(NSInteger, UIGestureRecognizerState) {
    // 没有触摸事件发生，所有手势识别的默认状态
    UIGestureRecognizerStatePossible,
    // 一个手势已经开始但尚未改变或者完成时
    UIGestureRecognizerStateBegan,
    // 手势状态改变
    UIGestureRecognizerStateChanged,
    // 手势完成
    UIGestureRecognizerStateEnded,
    // 手势取消，恢复至Possible状态
    UIGestureRecognizerStateCancelled,
    // 手势失败，恢复至Possible状态
    UIGestureRecognizerStateFailed,
    // 识别到手势识别
    UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded
};