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：

• UITapGestureRecognizer 点击
• 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

- (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]));
}

b.Swipe 手势 （轻扫）

• 核心属性
  
  • direction 方向

- (void)viewDidLoad {
    [super viewDidLoad];
    UISwipeGestureRecognizer *swipe = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipe:)];

    //上下左右 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];
}

上面两个手势 都是 一次性手势，即手势发生过程中，响应方法只执行依次

c. UILongPress 手势 长按

• 核心属性
  
  • minimumPressDuration 长按所需最小时间

- (void)viewDidLoad {
    [super viewDidLoad];
    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

三种拖拽方式

- (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 偏移
//        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);
}

2.变形 （transform）

• 什么是变形
  
  • 视图发生了 位移， 缩放， 旋转这样的变化叫做变形
• 如何实现视图的变形
  
  • 通过修改视图对象 transform属性就能完成变形
• transform属性
  
  • 类型 CGAffineTransform （结构体类型）
• 修改transform
  
  • translation 位移
  • scale 缩放
  • rotation 旋转
• CGAffineTransformMakeTranslation
• CGAffineTransformTranslate
• CGAffineTransformMakeScale
• CGAffineTransformScale
• CGAffineTransformMakeRotation
• CGAffineTransformRotate
• 清除视图的所有变形
  
  • CGAffineTransformIdentity

-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    //位移变化
    //CGAffineTransformMakeTranslation 变形是基于变形前的那个基础状态
//    self.imageView.transform = CGAffineTransformMakeTranslation(50, 50);
    //变形是在 当前 变形基础上 继续变形
    self.imageView.transform = CGAffineTransformTranslate(self.imageView.transform, 50, 50);


    //缩放变形
//    self.imageView.transform = CGAffineTransformMakeScale(1.1, 1.5);
    self.imageView.transform = CGAffineTransformScale(self.imageView.transform, 1.02, 1.02);

    //旋转变化
//    self.imageView.transform = CGAffineTransformMakeRotation(M_PI_4);
    self.imageView.transform = CGAffineTransformRotate(self.imageView.transform, M_PI_4);


    NSLog(@"transform %@",NSStringFromCGAffineTransform(self.imageView.transform));
}
- (IBAction)resetTranform:(id)sender {
//    CGAffineTransformIdentity 是个常量， 用该常量给 transform属性赋值 会 清空 transform 的所有变形
    self.imageView.transform = CGAffineTransformIdentity;
    NSLog(@"transform %@",NSStringFromCGAffineTransform(self.imageView.transform));
}

手势加变形综合应用

多手势同时出发必须使用 UIGestureRecognizerDelegate 代理

//手势代理方法  返回YES是可以同时触发
-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
    return YES;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    //拖拽
    UIPanGestureRecognizer *panGR = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(panGR:)];
    self.imageView.userInteractionEnabled = YES;//imageView默认关闭用户交互
    [self.view addGestureRecognizer:panGR];
    //捏合
    UIPinchGestureRecognizer *pinchGR = [[UIPinchGestureRecognizer alloc]initWithTarget:self action:@selector(pinchGR:)];
    pinchGR.delegate = self;
    [self.view addGestureRecognizer:pinchGR];
    //旋转
    UIRotationGestureRecognizer *rotationGR = [[UIRotationGestureRecognizer alloc]initWithTarget:self action:@selector(rotationGR:)];
    rotationGR.delegate = self;
    [self.view addGestureRecognizer:rotationGR];
    //点击
    UITapGestureRecognizer *tapGR = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tapGR:)];
    [self.view addGestureRecognizer:tapGR];

}

-(void)tapGR:(UITapGestureRecognizer*)gr {
    self.imageView.transform = CGAffineTransformIdentity;
}

-(void)rotationGR:(UIRotationGestureRecognizer*)gr {
    CGFloat rotation = gr.rotation;
    self.imageView.transform = CGAffineTransformRotate(self.imageView.transform, rotation);
    gr.rotation = 0;
}

-(void)pinchGR:(UIPinchGestureRecognizer*)gr {
    CGFloat scale = gr.scale;
    self.imageView.transform = CGAffineTransformScale(self.imageView.transform, scale, scale);
    gr.scale = 1;
}

-(void)panGR:(UIPanGestureRecognizer*)gr {
//    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];


    CGPoint translation = [gr translationInView:self.view];
    self.imageView.transform = CGAffineTransformTranslate(self.imageView.transform, translation.x, translation.y);
    [gr setTranslation:CGPointZero inView:self.view];
}

3.深入坐标系 （frame bounds center transform）

1.frame

• 类型：CGRect类型
• 作用：定位—视图的左顶点在父视图坐标系中的对应的点的坐标，以及视图在父视图中占据了多大的空间

2.bounds

• 类型：CGRect类型
• 作用：描述了视图自身的坐标系的顶点的值，以及视图自身的尺寸大小

3.center

• 类型：CGPoint类型
• 作用：描述了视图中心点在父视图坐标系下的位置

4.transform

• 类型：CGAffineTransform 类型

• 作用：描述视图的变形状态

• 通过更改bounds实现scroll滑动效果

//手势的事件方法
- (IBAction)panMove:(UIPanGestureRecognizer*)sender {
    CGPoint move = [sender translationInView:self.view];
    CGRect bounds = self.myView.bounds;
    if (move.y < 0) { //向上拖拽
        //bounds 应该越来越大
        bounds.origin.y += -move.y;
    }else if (move.y > 0) { //向下拖拽
        //bounds 应该越来越小
        bounds.origin.y -= move.y;
    }
    self.myView.bounds = bounds;

    [sender setTranslation:CGPointZero inView:self.view];
}

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