什么是手势?

用过苹果手机的朋友都知道,我们的屏幕上有个"小圆点","小圆点"当你对它做出不同动作的时候会有不同的响应事件,拖拽平移来移动它的位置,点击实现各种按键功能的实现,这样大大为用户提供了便利,并且可以有效地保护按键.

那么类似这种手势事件在我们的开发中是怎么实现的?

UIGestureRecognizer

UIKit中包含了UIGestureRecognizer类，用于检测发生在设备中的手势.UIGestureRecognizer是一个抽象类，定义了所有手势的基本行为，我们在开发中使用的是UIGestureRecognizer的子类:
UITapGestureRecognizer

    UIPinchGestureRecognizer

    UIRotationGestureRecognizer

    UISwipeGestureRecognizer

    UIPanGestureRecognizer

    UILongPressGestureRecognizer

见名知意,Tap(轻拍),Pinch(捏合),Rotation(旋转),Swipe(滑动,快速移动,是用于监测滑动的方向的),Pan(拖移,慢速移动,是用于监测偏移的量的),以及LongPress(长按)

下面来介绍一下这些手势最基本的使用方法:

@interface RootViewController ()
@property(nonatomic,strong)UIView *greenView;

@end

@implementation RootViewController

- (void)viewDidLoad {
    [super viewDidLoad];

self.view.backgroundColor =[ UIColor whiteColor];
    
    self.greenView = [[UIView alloc]initWithFrame:CGRectMake(100, 100, 100, 100)];
    _greenView.backgroundColor = [UIColor greenColor];
    [self.view addSubview:_greenView];
    
#pragma mark ---tap手势
    
    //创建手势,并初始化,使用initWithTarget: action:方法创建
    
    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapView:)];
    
    //设置属性
    tap.numberOfTapsRequired = 2;//次数
    tap.numberOfTouchesRequired = 2;//手指数
    
    //添加到视图上
//    [_greenView addGestureRecognizer:tap];
    
#pragma mark ----swipe手势
    
    UISwipeGestureRecognizer *swipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipeView:)];
    //属性
    swipe.direction = 0;
    
    
//    [_greenView addGestureRecognizer:swipe];
    
#pragma mark ----longPress手势
    
    UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressView:)];
    
    longPress.minimumPressDuration = 2;
    
//    [_greenView addGestureRecognizer:longPress];
    
#pragma mark ----- pan平移手势
    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panView:)];
//    [_greenView addGestureRecognizer:pan];
    
    #pragma mark  ----- pinch捏合手势
    UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchView:)];
//    [_greenView addGestureRecognizer:pinch];
    
#pragma mark ----- Rotation旋转手势
    
    UIRotationGestureRecognizer *rotation = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotationView:)];
//    [_greenView addGestureRecognizer:rotation];

}

//旋转手势事件
-(void)rotationView:(UIRotationGestureRecognizer *)sender{
    
    //rotation 旋转角度
    
    sender.view.transform = CGAffineTransformRotate(sender.view.transform, sender.rotation);
    
    //清除增量
    sender.rotation = 0.0;
    
}

//平移手势事件
-(void)panView:(UIPanGestureRecognizer *)sender{
    
    CGPoint point = [sender translationInView:_greenView];
//    sender.view.transform = CGAffineTransformMake(1, 0, 0, 1, point.x, point.y);
    
    //每次移动都是从原来的位置移动
//    sender.view.transform = CGAffineTransformMakeTranslation(point.x, point.y);
    
    //以上次的位置为标准
    sender.view.transform = CGAffineTransformTranslate(sender.view.transform, point.x, point.y);
    //增量置为0
    [sender setTranslation:CGPointZero inView:_greenView];
}

//长按手势事件
-(void)longPressView:(UILongPressGestureRecognizer *)sender{
    
    
    if (sender.state == UIGestureRecognizerStateBegan) {
        NSLog(@"长按状态!");
    }    
    
}

//捏合手势事件
-(void)pinchView:(UIPinchGestureRecognizer *)sender{
    
    //以上一次所方位标准
    sender.view.transform = CGAffineTransformScale(sender.view.transform, sender.scale, sender.scale);
    
    //重新设置缩放比例,1是正常缩放,小于1是缩小,大于1是放大
    sender.scale = 1;
}


-(void)swipeView:(UISwipeGestureRecognizer *)sender{
    //randomColor是自己写的一个UIColor的类目方法(随机色)
    _greenView.backgroundColor = [UIColor randomColor];
}

-(void)tapView:(UITapGestureRecognizer *)sender{
    
    _greenView.backgroundColor = [UIColor randomColor];
}

这就是开发中最基本的手势用法,大家都会了吗?