手势

手势识别器是对触摸事件做了封装，手势识别器本身起到了识别作用。

手势识别器是iOS中比较抽象的一个类，用于识别一个手势，所谓手势：有规律的触摸。

手势分类：

轻拍手势、长按手势

平移手势、轻扫手势

缩放手势、旋转手势

屏幕边界平移手势

系统提供的⼿势识别器这个抽象⽗类我们是不会直接使⽤的，⽽是根据需求使⽤特定的⼿势识别器创建对象，系统所提供的⼿势类型如下所⽰：

1.UITapGestureRecognizer是轻拍⼿势识别器，能识别轻拍操作

2.UILongPressGestureRecognizer是长按⼿势识别器，能识别长按操作

3.UIRotationGestureRecognizer是旋转⼿势识别器，能识别旋转操作

4.UIPinchGestureRecognizer是捏合⼿势识别器，能识别捏合操作

5.UIPanGestureRecognizer是平移⼿势识别器，能识别拖拽操作

6.UISwipeGestureRecognizer是轻扫⼿势识别器，能识别拖拽操作

7.UIScreenEdgePanGestureRecognizer是屏幕边缘轻扫识别器

应用步骤：

1.创建UIXXXGestureRecognizer对象，使⽤initWithTarget:action:⽅法

2.配置要识别的⼿势的相关信息

3.将⼿势添加到某个视图上

4.实现⼿势识别器⾥定义的⽅法

transform是view的⼀个重要属性，它在矩阵层⾯上改变view的显⽰状态，能实现view的缩放、旋转、平移等功能

平移：CGAffineTransformMakeTranslation

缩放：CGAffineTransformMakeScale

旋转：CGAffineTransformMakeRotation

- (void)viewDidLoad {
    [super viewDidLoad];

    UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(20, 50, 320, 500)];
    imageView.image = [UIImage imageNamed:@"love.jpg"];
    imageView.userInteractionEnabled = YES;

    //1、创建满足需求的手势，在创建时关联手势触发时的方法
    //2、配置手势的相关属性
    //3、将手势添加到需要执行操作的视图上面
    //4、实现手势方法，当触摸发生，手势识别器识别到相对应的触摸时，就会执行关联的方法。

    //轻拍手势 UITapGestureRecognizer
    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapAction:)];

    //设置属性
    //1、触发手势的手指个数

tap.numberOfTouchesRequired = 1;

//2、触发手势的轻拍次数

tap.numberOfTapsRequired = 2;

//让imageView添加轻拍手势

[imageView addGestureRecognizer:tap];

[tap release];

    //轻扫手势 UISwipeGestureRecognizer
    UISwipeGestureRecognizer *swipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipeAction:)];

    //指定清扫的方向

swipe.direction = UISwipeGestureRecognizerDirectionRight | UISwipeGestureRecognizerDirectionLeft;

[imageView addGestureRecognizer:swipe];

    [swipe release];


    //长按手势 UILongPressGestureRecognizer
    UILongPressGestureRecognizer *longpress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longpressAction:)];

    //长按手势触发的最短时间,默认是0.5

longpress.minimumPressDuration = 3.0;

[imageView addGestureRecognizer:longpress];

[longpress release];

    //缩放 UIPinchGestureRecognizer
    UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchAction:)];
    [imageView addGestureRecognizer:pinch];

[pinch release];

    //旋转 UIRotationGestureRecognizer
    UIRotationGestureRecognizer *rotate = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotateAction:)];
    [imageView addGestureRecognizer:rotate];

[rotate release];

    //平移 UIPanGestureRecognizer
    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panAction:)];
    [imageView addGestureRecognizer:pan];
    [pan release];

    [self.view addSubview:imageView];

    [imageView release];

    // Do any additional setup after loading the view.

}

- (void)panAction:(UIPanGestureRecognizer *)pan {
    //获取想要平移的视图
    UIImageView *imageView = (UIImageView *)pan.view;

    CGPoint p = [pan translationInView:imageView];

    //改变视图的形变属性
    imageView.transform = CGAffineTransformTranslate(imageView.transform, p.x, p.y);

    [pan setTranslation:CGPointZero inView:imageView];
}

- (void)rotateAction:(UIRotationGestureRecognizer *)rotate {
    //获取想要旋转的视图
    UIImageView *imageView = (UIImageView *)rotate.view;

    //改变imageView的形变属性
    imageView.transform = CGAffineTransformRotate(imageView.transform, rotate.rotation);
    rotate.rotation = 0;

//    imageView.transform =     CGAffineTransformMakeRotation(rotate.rotation);
}

- (void)pinchAction:(UIPinchGestureRecognizer *)pinch {
    //获取要进行缩放的视图
    UIImageView *imageView = (UIImageView *)pinch.view;

    //改变imageView的形变属性
    imageView.transform = CGAffineTransformScale(imageView.transform, pinch.scale, pinch.scale);
    pinch.scale = 1;

//    imageView.transform = CGAffineTransformMakeScale(pinch.scale, pinch.scale);
}

- (void)longpressAction:(UILongPressGestureRecognizer *)longpress {
    //获取手势关联的视图
    UIImageView *imageView = (UIImageView *)longpress.view;

    //修改图片
    [imageView setImage:[UIImage imageNamed:@"mao.jpg"]];
}

- (void)swipeAction:(UISwipeGestureRecognizer *)swipe {
    //获取手势关联的视图
    UIImageView *imageView = (UIImageView *)swipe.view;

    //修改图片
    [imageView setImage:[UIImage imageNamed:@"mao.jpg"]];
}

- (void)tapAction:(UITapGestureRecognizer *)tap {
    //获取手势关联的视图
    UIImageView *imageView = (UIImageView *)tap.view;

    //修改图片
    [imageView setImage:[UIImage imageNamed:@"mao.jpg"]];
}