然而使用touches方法监听触摸事件是有缺点的，比如要自定义view，所以iOS3.2之后苹果推出了手势识别功能UIGestureRecognizer。UIGestureRecognizer是一个抽象类，它的子类才能处理具体的某个手势。
具体有以下几种手势：
//点按手势
// UITapGestureRecognizer *tap = [UITapGestureRecognizer alloc]initWithTarget:<#(nullable id)#> action:<#(nullable SEL)#>
//长按手势 默认是触发两次
// UILongPressGestureRecognizer *longP = [UILongPressGestureRecognizer alloc]initWithTarget:<#(nullable id)#> action:<#(nullable SEL)#>
//轻扫手势 默认方向是往右
// UISwipeGestureRecognizer *swipe = [UISwipeGestureRecognizer alloc]initWithTarget:<#(nullable id)#> action:<#(nullable SEL)#>
//旋转手势
// UIRotationGestureRecognizer *rotation = [UIRotationGestureRecognizer alloc]initWithTarget:<#(nullable id)#> action:<#(nullable SEL)#>
//捏合手势
// UIPinchGestureRecognizer *pinch = [UIPinchGestureRecognizer alloc]initWithTarget:<#(nullable id)#> action:<#(nullable SEL)#>
//拖拽手势
// UIPanGestureRecognizer *pan = [UIPanGestureRecognizer alloc]initWithTarget:<#(nullable id)#> action:<#(nullable SEL)#>
实际运用：
@interface ViewController ()<UIGestureRecognizerDelegate>
@property (weak, nonatomic) IBOutlet UIImageView *imageView;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
[self setUpPinch];
[self setUpRotation];
[self setUpPan];
}
#pragma mark - 手势代理方法
// 是否允许开始触发手势
//- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
//{
// return NO;
//}
// 是否允许同时支持多个手势，默认是不支持多个手势
// 返回yes表示支持多个手势
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
return YES;
}
// 是否允许接收手指的触摸点
//- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch{
// // 获取当前的触摸点
// CGPoint curP = [touch locationInView:self.imageView];
//
// if (curP.x < self.imageView.bounds.size.width * 0.5) {
// return NO;
// }else{
// return YES;
// }
//}
#pragma mark - 点按手势
- (void)setUpTap
{
// 创建点按手势
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tap:)];
tap.delegate = self;
[_imageView addGestureRecognizer:tap];
}
- (void)tap:(UITapGestureRecognizer *)tap
{
NSLog(@"%s",__func__);
}
#pragma mark - 长按手势
// 默认会触发两次
- (void)setUpLongPress
{
UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPress:)];
[self.imageView addGestureRecognizer:longPress];
}
- (void)longPress:(UILongPressGestureRecognizer *)longPress
{
if (longPress.state == UIGestureRecognizerStateBegan) {
NSLog(@"%s",__func__);
}
}
#pragma mark - 轻扫
- (void)setUpSwipe
{
// 默认轻扫的方向是往右
UISwipeGestureRecognizer *swipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipe)];
swipe.direction = UISwipeGestureRecognizerDirectionUp;
[self.imageView addGestureRecognizer:swipe];
// 如果以后想要一个控件支持多个方向的轻扫，必须创建多个轻扫手势，一个轻扫手势只支持一个方向
// 默认轻扫的方向是往右
UISwipeGestureRecognizer *swipeDown = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipe)];
swipeDown.direction = UISwipeGestureRecognizerDirectionDown;
[self.imageView addGestureRecognizer:swipeDown];
}
- (void)swipe
{
NSLog(@"%s",__func__);
}
#pragma mark - 旋转手势
- (void)setUpRotation
{
UIRotationGestureRecognizer *rotation = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotation:)];
rotation.delegate = self;
[self.imageView addGestureRecognizer:rotation];
}
// 默认传递的旋转的角度都是相对于最开始的位置
- (void)rotation:(UIRotationGestureRecognizer *)rotation
{
self.imageView.transform = CGAffineTransformRotate(self.imageView.transform, rotation.rotation);
// 复位
rotation.rotation = 0;
// 获取手势旋转的角度
NSLog(@"%f",rotation.rotation);
}
#pragma mark - 捏合
- (void)setUpPinch
{
UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinch:)];
pinch.delegate = self;
[self.imageView addGestureRecognizer:pinch];
}
- (void)pinch:(UIPinchGestureRecognizer *)pinch
{
self.imageView.transform = CGAffineTransformScale(self.imageView.transform, pinch.scale, pinch.scale);
// 复位
pinch.scale = 1;
}
#pragma mark - 拖拽
- (void)setUpPan
{
UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)];
[self.imageView addGestureRecognizer:pan];
}
- (void)pan:(UIPanGestureRecognizer *)pan
{
// 获取手势的触摸点
// CGPoint curP = [pan locationInView:self.imageView];
// 移动视图
// 获取手势的移动，也是相对于最开始的位置
CGPoint transP = [pan translationInView:self.imageView];
self.imageView.transform = CGAffineTransformTranslate(self.imageView.transform, transP.x, transP.y);
// 复位
[pan setTranslation:CGPointZero inView:self.imageView];
// NSLog(@"%@",NSStringFromCGPoint(curP));
}
@end
