IOS之触摸与手势

一、触摸事件的处理方式
1.在IOS上，事件有多种形式：触摸事件，运动事件，远程控制事件。
2.触摸事件的处理方法
响应者类通过复写以下方法，可以监听触摸事件
(1)当一个或者多个手指触摸屏幕时：
- (void)touchesBegan:(NSSet *)touches withEvent:
(2)当一个或多个手指在屏幕上移动时:
- (void)touchesMoved:(NSSet *)touches withEvent:
(3)当一个或者多个手指离开屏幕时：
- (void)touchesEnded:(NSSet )touches withEvent:(UIEvent )event;
(4)当触摸序列被系统事件（诸如电话呼入）所取消时：
- (void)touchesCancelled:(NSSet *)touches withEvent:

---

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        //1.是否响应交互事件，默认为yes，UIImageView默认no
        //self.userInteractionEnabled = NO;

        //2.多点触摸，默认是no
        self.multipleTouchEnabled= YES;

    }
    return self;
}

----------

//1.触摸开始（当用户触摸屏幕时调用视图如下方法）
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    //UITouch --- 手指头的个数，一个touch表示一根手指（触摸点）
    //NSSet集合，保存UITouch对象，有几个触摸点，set里面就有几个触摸对象

    //点击的次数
    UITouch *touch = [touches anyObject];
    NSLog(@"tap count ：%ld",touch.tapCount);

    //触摸的阶段，触摸事件在屏幕上有一个周期，即触摸开始、移动、结束和中途取消。而通过phase可以查看当前触摸事件在一个周期中所处的状态。
    NSLog(@"phase :%ld",touch.phase);

    //在视图上的位置坐标，这里返回的位置是针对VIEW的坐标系
    CGPoint point = [touch locationInView:self];
    NSLog(@"location in View:%@",NSStringFromCGPoint(point));

    //在window上的位置
    CGPoint windowPoint = [touch locationInView:[UIApplication sharedApplication].keyWindow];
    NSLog(@"location in window :%@",NSStringFromCGPoint(windowPoint));

    //在视图上前一个点的坐标
    CGPoint prepoint = [touch previousLocationInView:self];
    NSLog(@"previouslocation in preview :%@",NSStringFromCGPoint(prepoint));


}

----------

//2.触摸移动
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [touches anyObject];

    //在视图上的位置坐标
    CGPoint point = [touch locationInView:self];
    NSLog(@"location in View:%@",NSStringFromCGPoint(point));

    //在视图上前一个点的坐标
    CGPoint prepoint = [touch previousLocationInView:self];
    NSLog(@"previouslocation in preview :%@",NSStringFromCGPoint(prepoint));

    //触摸的阶段
    NSLog(@"phase :%ld",touch.phase);

}

----------

//3.触摸结束
//- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
//{
//    UITouch *touch = [touches anyObject];
//    //触摸的阶段
//    NSLog(@"phase :%ld",touch.phase);
//}
//触摸取消，一般用不到
//- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event;

@end

eg:下面介绍一个处理轻击事件的Demo:

- (void)viewDidLoad {
    [super viewDidLoad];
    UIButton *button = [UIButton buttonWithType:UIButtonTypeSystem];
    button.frame = CGRectMake(20, 20, 100, 100);
    [button setTitle:@"ClickAction" forState:UIControlStateNormal];
    [button addTarget:self
               action:@selector(buttonAction:)
     forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];

}
----------
- (void)buttonAction:(UIButton *)btn
{
    NSLog(@"action");
}
----------
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [touches anyObject];
    if (touch.tapCount == 1)//单机
    {
        [self performSelector:@selector(singleTap)
                   withObject:nil
                   afterDelay:.2];
    }else if (touch.tapCount == 2)//双击
    {

        //*先取消单机,这一点很重要*
        [NSObject cancelPreviousPerformRequestsWithTarget:self
                                                 selector:@selector(singleTap)
                                                   object:nil];
        [self doubleTap];
    }       
}


----------

- (void)singleTap
{
    NSLog(@"单击");
}

- (void)doubleTap
{
     NSLog(@"双击");
}

2.运动事件

• (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event；
• (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event；
• (void)motionCancelled:(UIEventSubtype)motion withEvent:(UIEvent *)event；
  3.远程控制：（比如耳机线按钮控制音乐播放）
• (void)remoteControlReceivedWithEvent:(UIEvent *)event；

二、事件传递的过程

三、响应者链
响应者对象是一个能接受并处理事件的对象。UIResponser是所有响应者对象的基类。
响应者链表示一系列的响应者对象。事件被交由第一响应者对象处理，如果第一响应者不处理，事件被沿着响应者链向上传递，交给下一响应者（next responder）。
下面是一个next responder的view的类目

#import "UIView+ViewController.h"

@implementation UIView (ViewController)

- (UIViewController *)viewController
{
    id next = [self nextResponder];
    while (next != nil) {

        if ([next isKindOfClass:[UIViewController class]]) {
            UIViewController *viewCtrl = next;
            return viewCtrl;
        }

        next = [next nextResponder];
    }
    return nil;
}

@end

四、手势识别器
UIGestureRecognizer类是用于检测和识别用户使用设备时所用的手势。它是一个抽象类，定义了所有手势的基本行为。以下是UIGestureRecognizer子类，用于处理具体的用户手势行为：

UITapGestureRecognizer（轻击）
UIPinchGestureRecognizer（捏合）
UIPanGestureRecognizer（平移）
UISwipeGestureRecognizer（清扫）
UILongPressGestureRecognizer（长按）
UIRotationGestureRecognizer（旋转）

其中注意的是区别两种手势（一只手单击、双击）

eg:

  //一只手单击
    UITapGestureRecognizer *tap1 = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(singleTapOnce)];
    tap1.numberOfTapsRequired = 1;
    tap1.numberOfTouchesRequired = 1;
    [self.view addGestureRecognizer:tap1];

 //一只手双击
    UITapGestureRecognizer *tap2 = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(singleTapTwice)];
    tap2.numberOfTapsRequired = 2;
    tap2.numberOfTouchesRequired = 1;
    [self.view addGestureRecognizer:tap2]；
    [tap1 requireGestureRecognizerToFail:tap2];
----------
   //两只手单击
    UITapGestureRecognizer *tap3 = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(doubleTapOnce)];
    tap3.numberOfTouchesRequired = 2;
    [self.view addGestureRecognizer:tap3];

    //两只手双击
    UITapGestureRecognizer *tap4 = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(doubleTapTwice)];
    tap4.numberOfTapsRequired = 2;
    tap4.numberOfTouchesRequired = 2;
    [self.view addGestureRecognizer:tap4];

    //区别两种手势
    [tap3 requireGestureRecognizerToFail:tap4];
----------
     //一只手向右轻扫
    UISwipeGestureRecognizer *swip2 = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swip2Action)];
    swip2.direction = UISwipeGestureRecognizerDirectionRight;
    [self.view addGestureRecognizer:swip2];   
----------  
    //捏合手势
    UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchAction:)];

    [self.view addGestureRecognizer:pinch];
----------
UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressAction:)];
    [self.view addGestureRecognizer:longPress];
----------
//长按手势
- (void)longPressAction:(UILongPressGestureRecognizer *)sender
{
     NSLog(@"长按");
    if (sender.state == UIGestureRecognizerStateBegan)
    {
        NSLog(@"开始");
    }else if (sender.state == UIGestureRecognizerStateChanged)
    {
        NSLog(@"移动");
    }else if (sender.state == UIGestureRecognizerStateEnded)
    {
        NSLog(@"结束");
    }
}