ios 手势

1. 手势
将用户物理性的触屏操作变成对象存储起来，所有手势的父类 **UIGestureRecognizer **

系统将一些有特点的触屏操作封装成不同的手势类型包括以下几种（6种）：

UISwipeGestureRecognizer 轻扫
UILongPressGestureRecognizer 长按
UIPinchGestureRecognizer 捏合
UIPanGestureRecognizer 拖拽
UIRotationGestureRecognizer 旋转

如何使用手势？
step1:创建指定手势的实例，在创建时设定当该手势发生时，系统会自动发什么消息
** step2.设置手势的核心属性
** step3.将手势添加到某个视图中，当用户在该视图上做了相应的动作，就会触发手势，系统会捕获并调用手势的事件方法

**a.Taps手势 **
**核心属性 **

numberOfTapsRequired
numberOfTouchesRequired

b.Swipe 手势 （轻扫）
核心属性
direction 方向

上面两个手势 都是 一次性手势，即手势发生过程中，响应方法只执行一次

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c. UILongPress 手势 长按
核心属性
minimumPressDuration 长按所需最小时间

d. UIPan 手势 拖拽
e. UIPich 手势 捏合
f. UIRotation 手势 旋转

Taps手势：

- (void)viewDidLoad {
    [super viewDidLoad];
//    1.创建手势对象
    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tap:)];

    //2.设置手势的核心属性
    tap.numberOfTapsRequired = 5; //点几次
    tap.numberOfTouchesRequired = 1; //几个触摸点
    //3.将手势添加到某个视图中，当用户在该视图上做了相应的动作，就会触发手势，系统会捕获并调用手势的事件方法
    [self.myView addGestureRecognizer:tap];
}

-(void)tap:(UITapGestureRecognizer*)gr {
   
    NSLog(@"点击手势触发，点中的位置是 %@",  NSStringFromCGPoint([gr locationInView:self.myView]));
}

Swipe 手势 （轻扫）：

- (void)viewDidLoad {
    [super viewDidLoad];
//    创建手势对象
    UISwipeGestureRecognizer *swipe = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipe:)];
    
    //上下左右 设置 只 触发 左右
    swipe.direction = UISwipeGestureRecognizerDirectionLeft | UISwipeGestureRecognizerDirectionRight | UISwipeGestureRecognizerDirectionUp | UISwipeGestureRecognizerDirectionDown;

    [self.view addGestureRecognizer:swipe];
}

-(void)swipe:(UISwipeGestureRecognizer*)gr {
    NSLog(@"清扫方向 %lu", gr.direction);
    //结束父视图编辑  收键盘
    [self.view endEditing:YES];
}

UILongPress 手势 长按：

- (void)viewDidLoad {
    [super viewDidLoad];
//    创建手势对象
    UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(longPress:)];
    //设置长按触发最小时间
    longPress.minimumPressDuration = 2;
    [self.view addGestureRecognizer:longPress];
}
-(void)longPress:(UILongPressGestureRecognizer*)gr {
    NSLog(@"%@",  NSStringFromCGPoint([gr locationInView:self.view]));
    if (gr.state == UIGestureRecognizerStateBegan) {
            NSLog(@"开始长按");
    }else if(gr.state == UIGestureRecognizerStateChanged) {
            NSLog(@"移动");
    }else if(gr.state == UIGestureRecognizerStateEnded) {
            NSLog(@"长按手势结束");
    }
}

d. UIPan 手势 拖拽

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

-(void)pan:(UIPanGestureRecognizer*)gr {
    NSLog(@"1--%@",NSStringFromCGPoint([gr locationInView:self.view]));
    NSLog(@"2--%@",NSStringFromCGPoint([gr translationInView:self.view]));
    //方式一
    if (gr.state == UIGestureRecognizerStateBegan) {
        self.startPos = self.imageView.center;
    }else {
        CGPoint translation = [gr translationInView:self.view];
        CGPoint center = self.imageView.center;
        center.x = self.startPos.x + translation.x;
        center.y = self.startPos.y + translation.y;
        self.imageView.center = center;
    }
    
    //方式二
//    CGPoint translation = [gr translationInView:self.view];
//    CGPoint center = self.imageView.center;
//    center.x += translation.x;
//    center.y += translation.y;
//    self.imageView.center = center;
//    [gr setTranslation:CGPointZero inView:self.view];
    
    //方式三
//    if (gr.state == UIGestureRecognizerStateBegan) {
//        //手势开始时 记录 起始位置
//        self.startPos = [gr locationInView:self.view];
//    }else if (gr.state == UIGestureRecognizerStateChanged){
//        //获取本次 移动的位置
//        CGPoint move = [gr locationInView:self.view];
//        //图片的位置的等于当前位置 加上 移动位置-上次位置 的 便宜
//        CGPoint center = self.imageView.center;
//        center.x += move.x - self.startPos.x;
//        center.y += move.y - self.startPos.y;
//        self.imageView.center = center;
//        //设置本次位置  为下次的 起始位置
//        self.startPos = move;
//    }
}

e. UIPich 手势 捏合

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

-(void)pinch:(UIPinchGestureRecognizer*)gr {
    NSLog(@"速率 %.2f",gr.velocity);
    NSLog(@"缩放比 %.2f",gr.scale);
}

f. UIRotation 手势 旋转

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

-(void)rotation:(UIRotationGestureRecognizer*)gr {
    NSLog(@"%.2f",gr.rotation);
}