UIGestureRecognizer

iOS 3.2之后，苹果推出了手势识别功能（Gesture Recognizer）,
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的手势
UITapGestureRecognizer(敲击)
UIPinchGestureRecognizer(捏合，用于缩放)
UIPanGestureRecognizer(拖拽)
UISwipeGestureRecognizer(轻扫)
UIRotationGestureRecognizer(旋转)
UILongPressGestureRecognizer(长按)

#import "ViewController.h"

@interface ViewController ()<UIGestureRecognizerDelegate>
@property (weak, nonatomic) IBOutlet UIImageView *myImageView;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
//    [self tapTest];
//    [self tapTest2];
//    [self longPressTest];
//    [self swipeTest];
//    [self panTest];
//    [self pinchTest];
//    [self rotateTest];
    [self rotateAndPinchTest];
}

-(void)rotateAndPinchTest
{
//    旋转和缩放手势识别器同时使用,需要设置代理
    
    UIRotationGestureRecognizer * rotationGestureRecognizer = [[UIRotationGestureRecognizer alloc] init];
    [rotationGestureRecognizer addTarget:self action:@selector(onRotationListener:)];
    rotationGestureRecognizer.delegate = self;
    [self.myImageView addGestureRecognizer:rotationGestureRecognizer];
    
    UIPinchGestureRecognizer * pinchGestureRecognizer = [[UIPinchGestureRecognizer alloc] init];
    [pinchGestureRecognizer addTarget:self action:@selector(onPinchListener:)];
    pinchGestureRecognizer.delegate = self;
    [self.myImageView addGestureRecognizer:pinchGestureRecognizer];
}
/**
 是否允许多个手势识别器同时使用
 */
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
    return YES;
}


-(void)rotateTest
{
    //旋转手势识别器
    UIRotationGestureRecognizer * rotationGestureRecognizer = [[UIRotationGestureRecognizer alloc] init];
    [rotationGestureRecognizer addTarget:self action:@selector(onRotationListener:)];
    [self.myImageView addGestureRecognizer:rotationGestureRecognizer];
}

-(void)pinchTest
{
    //缩放手势识别器
    UIPinchGestureRecognizer * pinchGestureRecognizer = [[UIPinchGestureRecognizer alloc] init];
    [pinchGestureRecognizer addTarget:self action:@selector(onPinchListener:)];
    [self.myImageView addGestureRecognizer:pinchGestureRecognizer];
}

-(void)panTest
{
    //初始化拖拽手势识别器
    UIPanGestureRecognizer * panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(onPanListener:)];
    [self.myImageView addGestureRecognizer:panGestureRecognizer];
}

-(void)swipeTest
{
    //创建手势识别器
    UISwipeGestureRecognizer * swipGestureRecognizer = [[UISwipeGestureRecognizer alloc] init];
    //给手势识别器添加对应的回调
    [swipGestureRecognizer addTarget:self action:@selector(onSwipeListener)];
    //设置监听滑动反向
    swipGestureRecognizer.direction = UISwipeGestureRecognizerDirectionDown;
    //给view添加手势
    [self.myImageView addGestureRecognizer:swipGestureRecognizer];
}

-(void)longPressTest
{
    //创建长按手势识别器
    UILongPressGestureRecognizer * longPressGestureRecognizer = [[UILongPressGestureRecognizer alloc] init];
    //给手势识别器添加对应的回调
    [longPressGestureRecognizer addTarget:self action:@selector(onLongClickListener)];
    //给view添加手势识别器
    [self.myImageView addGestureRecognizer:longPressGestureRecognizer];
}

-(void)tapTest2
{
    //创建点击手势识别器
    UITapGestureRecognizer * tapGestureRecognizer = [[UITapGestureRecognizer alloc] init];
    //设置代理可以对点击事件进行特殊处理
    tapGestureRecognizer.delegate = self;
    //给手势识别器添加对应的回调
    [tapGestureRecognizer addTarget:self action:@selector(onTapClickListener)];
    //给view添加手势识别器
    [self.myImageView addGestureRecognizer:tapGestureRecognizer];
}

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
    CGPoint point = [touch locationInView:touch.view];
    if (point.x < self.myImageView.frame.size.width * 0.5) {
        return YES;
    }
    return NO;
}

-(void)tapTest
{
    //创建点击手势识别器
    UITapGestureRecognizer * tapGestureRecognizer = [[UITapGestureRecognizer alloc] init];
    //给手势识别器添加对应的回调
    [tapGestureRecognizer addTarget:self action:@selector(onTapClickListener)];
    //给view添加手势识别器
    [self.myImageView addGestureRecognizer:tapGestureRecognizer];
}

-(void)onTapClickListener
{
    NSLog(@"点一下");
}
-(void)onLongClickListener
{
    NSLog(@"长按了uyihui");
}
-(void)onSwipeListener
{
    NSLog(@"滑动了");
}

-(void)onPanListener:(UIPanGestureRecognizer *)pan
{
    CGPoint translation = [pan translationInView:pan.view];
    CGPoint center = pan.view.center;
    center.x += translation.x;
    center.y += translation.y;
    pan.view.center = center;
    //每次相对于上一次
    [pan setTranslation:CGPointZero inView:pan.view];
}

-(void)onPinchListener:(UIPinchGestureRecognizer *)pinch
{
    pinch.view.transform = CGAffineTransformScale(pinch.view.transform, pinch.scale, pinch.scale);
    //每次都相对于上一次缩放
    pinch.scale = 1;
}

-(void)onRotationListener:(UIRotationGestureRecognizer *)rotation
{
    rotation.view.transform = CGAffineTransformRotate(rotation.view.transform, rotation.rotation);
    //每次相对于上一次旋转
    rotation.rotation = 0;
}
@end