如何识别oneTap / doubleTap？

Question

我知道使用Apple API过滤oneTap / doubleTap。代码如下。

UITapGestureRecognizer *doubleTapGestureRecognizer = [[UITapGestureRecognizer alloc]
                        initWithTarget:self action:@selector(handleDoubleTap:)];
doubleTapGestureRecognizer.numberOfTapsRequired = 2;


[self addGestureRecognizer:doubleTapGestureRecognizer];


UITapGestureRecognizer *singleTapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleSingleTap:)];
singleTapGestureRecognizer.numberOfTapsRequired = 1;

**[singleTapGestureRecognizer requireGestureRecognizerToFail: doubleTapGestureRecognizer];**

[self addGestureRecognizer:singleTapGestureRecognizer];

但是oneTap / doubleTap checkDelayTime感觉太长了（约0.5秒？）。 一般来说App的用户反应非常快。虽然0.5秒通常是短时间。但在移动设备环境中是长期的，因为用户的反应非常重要。

说到这一点，YouTubeApp 有一个非常完美的算法，关于过滤oneTap / doubleTap的时刻。 oneTap-doubleTap checkDelay是VeryVeryShort完美优化。

oneTap（show / hidden controlBar）

doubleTap（完整/默认videoScreenSize）

如何实施YoutubeApp？关于oneTap-doubleTap过滤不使用requireGestureRecognizerToFail选择器。关于非常短的延迟oneTap-doubleTap区分。

我认为YoutubeApp不使用requireGestureRecognizer选择器。

Answer 1

执行此操作的最简单方法是继承 UITapGestureRecognizer ，而不是一般的UIGestureRecognizer。

像这样：

#import <UIKit/UIGestureRecognizerSubclass.h>

#define UISHORT_TAP_MAX_DELAY 0.2
@interface UIShortTapGestureRecognizer : UITapGestureRecognizer

@end

简单地实施：

@implementation UIShortTapGestureRecognizer

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    [super touchesBegan:touches withEvent:event];
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(UISHORT_TAP_MAX_DELAY * NSEC_PER_SEC)), dispatch_get_main_queue(), ^
    {
        // Enough time has passed and the gesture was not recognized -> It has failed.
        if  (self.state != UIGestureRecognizerStateRecognized)
        {
            self.state = UIGestureRecognizerStateFailed;
        }
    });
}
@end

Answer 2

没有手势识别器，这是最容易的。然后你可以控制延迟。下面的代码是Apple在我的一个项目中使用的原始文档的变体。我有blog post that talks about it as well。

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
 UITouch *touch = [touches anyObject];
if (touch.tapCount == 2) {
//This will cancel the singleTap action
[NSObject cancelPreviousPerformRequestsWithTarget:self];
}

}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
 UITouch *touch = [touches anyObject];
if (touch.tapCount == 1) {
  //if they tapped within the coin then place the single tap action to fire after a delay of 0.3
  if (CGRectContainsPoint(coin.frame,[touch locationInView:self.view])){
    //this is the single tap action being set on a delay
  [self performSelector:@selector(onFlip) withObject:nil afterDelay:0.3];
  }else{
   //I change the background image here
  }
 } else if (touch.tapCount == 2) {
  //this is the double tap action
  [theCoin changeCoin:coin];
 }
}

Answer 3

您需要做的只是添加额外的代码行以使用requireGestureRecognizerToFail

[singleTapRecognizer requireGestureRecognizerToFail:doubleTapRecognizer];

然后整个代码变为：

UITapGestureRecognizer *doubleTapRecognizer = [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(beginComicTransitions:)] autorelease];    
doubleTapRecognizer.numberOfTapsRequired = 2;
doubleTapRecognizer.numberOfTouchesRequired = 1;
doubleTapRecognizer.delegate = self;   

UITapGestureRecognizer *singleTapRecognizer = [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(bringMenu:)] autorelease];    
singleTapRecognizer.numberOfTapsRequired = 1;
singleTapRecognizer.numberOfTouchesRequired = 1;
singleTapRecognizer.delegate = self;

[singleTapRecognizer requireGestureRecognizerToFail:doubleTapRecognizer];

这里的requireGestureRecognizerToFail表示：

• 如果未识别双击，则单击即可识别
• 如果识别出双击，则无法识别单击

swift版本代码是：

    let doubleTap = UITapGestureRecognizer(target: self, action: "doubleTapped:")
    doubleTap.numberOfTapsRequired = 2
    doubleTap.numberOfTouchesRequired = 1
    self.scrollView.addGestureRecognizer(doubleTap)

    let singleTap = UITapGestureRecognizer(target: self, action: "singleTap:")
    singleTap.numberOfTapsRequired = 1
    singleTap.numberOfTouchesRequired = 1
    self.scrollView.addGestureRecognizer(singleTap)

    singleTap.requireGestureRecognizerToFail(doubleTap)

Answer 4

这是一个用于双击的简单自定义手势识别器，您可以在其中指定点击之间允许的最长时间。这是基于@Walters的答案。

PbDoubleTapGestureRecognizer.h：

@interface PbDoubleTapGestureRecognizer : UIGestureRecognizer

@property (nonatomic) NSTimeInterval maximumDoubleTapDuration;

@end

PbDoubleTapGestureRecognizer.m：

#import "PbDoubleTapGestureRecognizer.h"
#import <UIKit/UIGestureRecognizerSubclass.h>

@interface PbDoubleTapGestureRecognizer ()
@property (nonatomic) int tapCount;
@property (nonatomic) NSTimeInterval startTimestamp;
@end

@implementation PbDoubleTapGestureRecognizer

- (id)initWithTarget:(id)target action:(SEL)action {
    self = [super initWithTarget:target action:action];
    if (self) {
        _maximumDoubleTapDuration = 0.3f; // assign default value
    }
    return self;
}

-(void)dealloc {
    [NSObject cancelPreviousPerformRequestsWithTarget:self];
}

- (void)reset {
    [super reset];

    [NSObject cancelPreviousPerformRequestsWithTarget:self];

    self.tapCount = 0;
    self.startTimestamp = 0.f;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesBegan:touches withEvent:event];

    if (touches.count != 1 ) {
        self.state = UIGestureRecognizerStateFailed;
    } else {
        if (self.tapCount == 0) {
            self.startTimestamp = event.timestamp;
            [self performSelector:@selector(timeoutMethod) withObject:self afterDelay:self.maximumDoubleTapDuration];
        }
        self.tapCount++;
    }
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesMoved:touches withEvent:event];
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesEnded:touches withEvent:event];

    if (self.tapCount > 2) {
        self.state = UIGestureRecognizerStateFailed;
    } else if (self.tapCount == 2 && event.timestamp < self.startTimestamp + self.maximumDoubleTapDuration) {
        [NSObject cancelPreviousPerformRequestsWithTarget:self];
        NSLog(@"Recognized in %f", event.timestamp - self.startTimestamp);
        self.state = UIGestureRecognizerStateRecognized;
    }
}

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesCancelled:touches withEvent:event];
    self.state = UIGestureRecognizerStateFailed;
}

- (void)timeoutMethod {
    self.state = UIGestureRecognizerStateFailed;
}

@end

你可以像这样使用它：

PbDoubleTapGestureRecognizer *doubleTapGr = [[PbDoubleTapGestureRecognizer alloc]initWithTarget:self action:@selector(_doubleTapAction)];
doubleTapGr.maximumDoubleTapDuration = 0.4;
[yourView addGestureRecognizer:doubleTapGr];

您可以将其与requireGestureRecognizerToFail:结合使用，以获取所要求的行为。

Answer 5

eladleb's答案的Swift 3.1 版本。

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent) {
        super.touchesBegan(touches, with: event)

        DispatchQueue.main.asyncAfter(deadline: .now() + 0.3) { [weak self] in
            if self?.state != .recognized {
                self?.state = .failed
            }
        }
    }

Answer 6

如果您已经在按钮或视图上附加了动作，那么这是一个更简单的答案。首先，更改IBAction，使其包含UIEvent（不要忘记将其重新连接到您的按钮或在Storyboard中查看）：

-(IBAction)buttonAction:(id)sender forEvent:(UIEvent*)event

下一步，您可以在您的事件中捕获事件的触摸，然后轻松测试点击次数：

-(IBAction)buttonAction:(id)sender forEvent:(UIEvent*)event {

     UITouch* firstTouch = nil;
     if ((nil != ((firstTouch = event.allTouches.allObjects.firstObject)))
         && (2 == firstTouch.tapCount))
     {
         // do something for double-tap
     } else {
         // do something for single-tap
     }
}

您可以针对其他事件参数（例如长按）使用其他情况扩展此解决方案。

Answer 7

@interface NaMeClass ()

@property (nonatomic, strong) UITapGestureRecognizer * singleTap;
@property (nonatomic, strong) NSTimer *timer;

@end

// ... ...代码

//viewDidLoad
self.singleTap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tapIcon:)];
self.singleTap.numberOfTapsRequired = 1;
self.singleTap.cancelsTouchesInView = YES;
self.singleTap.delaysTouchesBegan = YES;
[self addGestureRecognizer:self.singleTap];

//.....code

-(void)tapIcon:(UITapGestureRecognizer *)tapGesture
{
    if (tapGesture.state == UIGestureRecognizerStateEnded){
        if (!self.timer) {
            self.timer = [NSTimer scheduledTimerWithTimeInterval:0.2
                         target:self selector:@selector(singleTap) userInfo:nil repeats:NO];
        }else{
            [self doubleTap];
     }
}

}

-(void)singleTap{
    [self.timer invalidate];
    self.timer = nil;
    NSLog(@"1111111111111");
}

-(void)doubleTap{
    [self.timer invalidate];
    self.timer = nil;
    NSLog(@"22222222222");
}