IOS开发之——事件处理-手势识别
文章搬运来源:https://blog.csdn.net/Calvin_zhou/article/details/111307617
作者:PGzxc
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一 概述
- 监听触控事件的做法
- 手势识别器——UIGestureRecognizer
- 手势识别示例
二 监听触摸事件的做法
2.1 如果想监听一个view上面的触摸事件,之前的做法是
- 自定义一个view
- 实现view的touches方法,在方法内部实现具体的处理代码
2.2 通过touches方法监听view触摸事件,有很明显的几个缺点
- 必须得自定义view
- 由于是在view内部的touches方法中监听触摸事件,因此默认情况下,无法让其他外界对象监听view的触摸事件
- 不容易区分用户的具体手势行为
2.3 手势识别功能
IOS3.2之后,苹果推出了手势识别功能(Guesture Recognizer),在触摸事件处理方面,大大简化了开发者的开发难度
三 手势识别器——UIGestureRecognizer
3.1手势识别器介绍
- 为了完成手势识别,必须借助手势识别器——UIGestureRecognizer
- 利用UIGestureRecognizer,能轻松识别用户在某个view上面做的一些常见手势
3.2 手势识别器的常见行为
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
四 手势识别示例
4.1 UITapGestureRecognizer
手势
UITapGestureRecognizer *tap=[[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tap:)];
//点按多少次才能触发
tap.numberOfTapsRequired=2;
//必须多少个手指触摸才能触发手势
//tap.numberOfTouchesRequired=2;
tap.delegate=self;
[_imageView addGestureRecognizer:tap];
说明
- tap.numberOfTapsRequired:点击多少次才能触发
- tap.numberOfTouchesRequired:多少手势触发
方法
-(void)tap:(UITapGestureRecognizer *)tap
{
NSLog(@"tap");
}
4.2 UILongPressGestureRecognizer
手势
UILongPressGestureRecognizer *longPress=[[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(longPress:)];
[_imageView addGestureRecognizer:longPress];
方法
-(void)longPress:(UILongPressGestureRecognizer *)longPress
{
if (longPress.state==UIGestureRecognizerStateBegan) {
NSLog(@"longPress");
}
}
4.3 UISwipeGestureRecognizer
手势
//swip 一个手势只能识别一个方向
UISwipeGestureRecognizer *swipe=[[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swip:)];
swipe.direction=UISwipeGestureRecognizerDirectionRight;
[_imageView addGestureRecognizer:swipe];
方法
-(void)swip:(UISwipeGestureRecognizer *)swipe
{
NSLog(@"swipe");
}
4.4 UIRotationGestureRecognizer
添加手势
UIRotationGestureRecognizer *rotation=[[UIRotationGestureRecognizer alloc]initWithTarget:self action:@selector(rotation:)];
[_imageView addGestureRecognizer:rotation];
方法
-(void)rotation:(UIRotationGestureRecognizer *)rotation
{
NSLog(@"%f",rotation.rotation);
//_imageView.transform=CGAffineTransformMakeRotation(rotation.rotation);
_imageView.transform=CGAffineTransformRotate(_imageView.transform, rotation.rotation);
rotation.delegate=self;
rotation.rotation=0;
}
4.5 UIPinchGestureRecognizer
手势
UIPinchGestureRecognizer *pinch=[[UIPinchGestureRecognizer alloc]initWithTarget:self action:@selector(pinch:)];
[_imageView addGestureRecognizer:pinch];
pinch.delegate=self;
[self addRotation];
方法
-(void)pinch:(UIPinchGestureRecognizer *)pinch
{
_imageView.transform=CGAffineTransformScale(_imageView.transform, pinch.scale, pinch.scale);
//复位
pinch.scale=1;
}
4.6 UIPanGestureRecognizer
手势
UIPanGestureRecognizer *pan=[[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(pan:)];
[_imageView addGestureRecognizer:pan];
方法
-(void)pan:(UIPanGestureRecognizer *)pan
{
CGPoint trans=[pan translationInView:_imageView];
_imageView.transform=CGAffineTransformTranslate(_imageView.transform, trans.x, trans.y);
//复位
[pan setTranslation:CGPointZero inView:_imageView];
NSLog(@"%@",NSStringFromCGPoint(trans));
}