iOS的触摸事件的用法以及和手势识别器的区别

1、首先来介绍下触摸事件和手势识别器的利与弊

触摸事件和手势识别器二者之间有直接的关系
手势识别器是在触摸事件的基础上演变过来的
当我们用到触摸事件时 默认的uiview是没有什么效果的  只能自定义view才能实现事件的触摸
通常用到的方法如下：
– touchesBegan:withEvent: 
– touchesMoved:withEvent: 
– touchesEnded:withEvent: 
- touchesCancelled:withEvent:

而手势识别器是在触摸事件的基础上而封装的
为什么要封装呢？因为直接touchs方法来定位手势比较麻烦。在还没有UIGestureRecognizer的时代，用touchs也可以计算出博文中说的几种常用手势：点，滑动，拖等等。这些手势都非常常用，每个开发者想要监视这些手势的时候都要自己判断一遍，每个人都在重复造轮子。那把这些手势封装出来标准化，就有了UIGestureRecognizer和它对应的子类手势了。 那为什么还要有touchs等方法存在呢？因为UIGestureRecognizer几种手势比较有限，有的游戏应用需要搞些特别的手势，那就用touchs这些方法来定义了。

2、使用手势步骤

使用手势很简单，分为两步：
创建手势实例。当创建手势时，指定一个回调方法，当手势开始，改变、或结束时，回调方法被调用。
添加到需要识别的View中。每个手势只对应一个View，当屏幕触摸在View的边界内时，如果手势和预定的一样，那就会回调方法。
ps：一个手势只能对应一个View，但是一个View可以有多个手势。
建议在真机上运行这些手势,模拟器操作不太方便，可能导致你认为手势失效。

3、手势的介绍

UITapGestureRecognizer  （敲击）
UIPinchGestureRecognizer (捏合，由于缩放)
UIPanGestureRecognizer   (拖拽)
UISwipeGestureRecognizer (轻扫)
UIRotationGestureRecognizer(旋转)
UILongPressGestureRecognizer(长按)

4、敲击手势的用法（其他手势类同）代码如下：

//创建手势识别对象
    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] init];
    //连续敲击二次手势才能识别成功
    tap.numberOfTapsRequired  = 2;
    //需要一根手指触摸
    tap.numberOfTouchesRequired = 2;
    //添加手势识别器对象到对应的uiview
    [self.iconView addGestureRecognizer:tap];
    
    //添加监听方法（识别到对应的手势就会监听事件）
    [tap addTarget:self action:@selector(btClick:)];

5、缩放 + 旋转

#import "ViewController.h"

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

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.iconView.userInteractionEnabled = YES;
    // Do any additional setup after loading the view, typically from a nib.
    [self testPichAndRoate];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
-(void) testPichAndRoate
{
    //[self testPich];
    [self testRoate];
}
-(void) testPich
{
    UIPinchGestureRecognizer *pich = [[UIPinchGestureRecognizer alloc] init];
    pich.delegate = self;
    [self.iconView addGestureRecognizer:pich];
    [pich addTarget:self action:@selector(pinchView:)];
}
-(void) pinchView:(UIPinchGestureRecognizer *)pinchView
{
    pinchView.view.transform = CGAffineTransformScale(pinchView.view.transform, pinchView.scale, pinchView.scale);
    pinchView.scale = 1;//必写
}
-(void) testRoate
{
    UIRotationGestureRecognizer *roate = [[UIRotationGestureRecognizer alloc] init];
    roate.delegate = self;
    [self.iconView addGestureRecognizer:roate];
    [roate addTarget:self action:@selector(roateView:)];
}
-(void) roateView:(UIRotationGestureRecognizer *)roate
{
    roate.view.transform = CGAffineTransformRotate(roate.view.transform, roate.rotation);
    roate.rotation = 0;//必写
}
@end

6、拖动

#import "ViewController.h"

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIView *panView;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] init];
    [self.panView addGestureRecognizer:pan];
    [pan addTarget:self action:@selector(panTuoDong:)];
    
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
-(void)panTuoDong:(UIPanGestureRecognizer *)pan
{
    switch (pan.state) {
        case UIGestureRecognizerStateBegan: // 开始触发手势
            
            break;
            
        case UIGestureRecognizerStateEnded: // 手势结束
            
            break;
            
        default:
            break;
    }
    //在view上挪动的距离
   CGPoint transtation = [pan translationInView:pan.view];
    CGPoint center = pan.view.center;
    center.x += transtation.x;
    center.y += transtation.y;
    pan.view.center = center;
    
    //清除挪动的距离
    [pan setTranslation:CGPointZero inView:pan.view];
}

@end