OC_手势

一、有哪些手势?

1.1、一次性手势
Tap: 点击 Swipe:轻扫

1.2、连续性手势
LongPress: 长按 Pan:拖动 Pinch:捏合,扩张 Rotation: 旋转

1.3、手势的本质
系统将用户针对屏幕的物理性动作,转换成数据储存起来,这个数据就是封装的对象,所以手势这种物理性的操作最后都是一个一个的对象

二、如何使用手势
step1:创建具体的手势对象
step2:指定发生具体手势时，响应的方法
step3:设置手势对象的常用属性
step4:将手势对象与具体的某个view关联起来

2.1、UITapGestureRecognizer

UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapmethod:)];
    tap.numberOfTouchesRequired = 2;//点击出点需要几个点
    tap.numberOfTapsRequired = 2;//连续点击几次才能引发手势事件
//上面两个参数默认不写的时候，系统默认是1；
    [self.view addGestureRecognizer:tap];

//如何判断点击的地方是在视图的什么地方？

//在tap引发的时间中传入的UIGestureRecognizer 有一个方法:[tap locationInView:tpbview];
//这个方法可以得到一个CGPoint, 双指头点击的时候这个方法是无效的，因为无论点击哪里得到的都是同一个CGPoint

2.2、UISwipeGestureRecognizer

- (void)viewDidLoad {
    [super viewDidLoad];
    
    UISwipeGestureRecognizer *swipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipemethod:)];
    swipe.direction = UISwipeGestureRecognizerDirectionLeft| UISwipeGestureRecognizerDirectionRight;
}

-(void)swipemethod:(UIGestureRecognizer *)swipe{
 
    NSLog(@"123");
}

2.3、UILongPressGestureRecognizer

- (void)viewDidLoad {
    [super viewDidLoad];
    UILongPressGestureRecognizer *LongPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(LongPressmethod:)];
 LongPress.minimumPressDuration = 2;
 [self.view addGestureRecognizer: LongPress];
}

-(void) LongPressmethod:(UIGestureRecognizer *) LongPress{
if (LongPress.state == UIGestureRecognizerStateBegan) {
        NSLog(@"began");
    }else if (LongPress.state == UIGestureRecognizerStateChanged){
        NSLog(@"change");
    }else if (LongPress.state == UIGestureRecognizerStateEnded){
        NSLog(@"end");
    }
   CGPoint point = [LongPress locationInView:self.view];
NSLog(@"%@",NSStringFromCGPoint(point));
}
//长按方法在长按时长达到时间后，执行一次，抬起的时候也执行一次

2.4、UIPanGestureRecognizer

- (void)viewDidLoad {
    [super viewDidLoad];
    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)];
    [self.view addGestureRecognizer:pan];
}

-(void)pan:(UIPanGestureRecognizer *)pan{
    
    //当前位置
    CGPoint point = [pan locationInView:self.view];
    //相对于一开始按下的位置的位移
    CGPoint point2 = [pan translationInView:self.view];
    
    NSLog(@"point1:%@",NSStringFromCGPoint(point));
    NSLog(@"point2:%@",NSStringFromCGPoint(point2));
}

2.5、UIPinchGestureRecognizer

- (void)viewDidLoad {
    [super viewDidLoad];
    UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinch:)];
    
    [self.view addGestureRecognizer:pinch];
}
- (void)pinch:(UIPinchGestureRecognizer *)pin{
    CGFloat velocity = pin.velocity;//捏合或者扩展的速度快慢
    CGFloat scale = pin.scale;//捏合的动作比例
    
    NSLog(@"velocity = %lf",velocity);
    NSLog(@"scale = %lf",scale);
    
}