UITapGestureRecognizer - 使其在触摸的工作下来，不能碰了？(UITapGe

我正在用水龙头事件是非常时间敏感的，所以我很好奇，如果有可能使UITapGestureRecognizer激活时，用户只需触地，而不是要求他们去触摸起来呢？

Answer 1:

创建自定义TouchDownGestureRecognizer子类，并在实施的touchesBegan姿态：

TouchDownGestureRecognizer.h

#import <UIKit/UIKit.h>

@interface TouchDownGestureRecognizer : UIGestureRecognizer

@end

TouchDownGestureRecognizer.m

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

@implementation TouchDownGestureRecognizer
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    if (self.state == UIGestureRecognizerStatePossible) {
        self.state = UIGestureRecognizerStateRecognized;
    }
}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
    self.state = UIGestureRecognizerStateFailed;
}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
    self.state = UIGestureRecognizerStateFailed;
}


@end

执行：

#import "TouchDownGestureRecognizer.h"
    TouchDownGestureRecognizer *touchDown = [[TouchDownGestureRecognizer alloc] initWithTarget:self action:@selector(handleTouchDown:)];
    [yourView addGestureRecognizer:touchDown];

-(void)handleTouchDown:(TouchDownGestureRecognizer *)touchDown{
    NSLog(@"Down");
}

---

斯威夫特实现：

import UIKit
import UIKit.UIGestureRecognizerSubclass

class TouchDownGestureRecognizer: UIGestureRecognizer
{
    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent)
    {
        if self.state == .Possible
        {
            self.state = .Recognized
        }
    }

    override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent)
    {
        self.state = .Failed
    }

    override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent)
    {
        self.state = .Failed
    }
}

---

下面是斯威夫特语法2017年贴：

import UIKit.UIGestureRecognizerSubclass

class SingleTouchDownGestureRecognizer: UIGestureRecognizer {
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent) {
        if self.state == .possible {
            self.state = .recognized
        }
    }
    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent) {
        self.state = .failed
    }
    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent) {
        self.state = .failed
    }
}

请注意，这是一个简易替换为UITap 。 因此，在这样的代码...

func add(tap v:UIView, _ action:Selector) {
    let t = UITapGestureRecognizer(target: self, action: action)
    v.addGestureRecognizer(t)
}

你可以安全地交换到....

func add(hairtriggerTap v:UIView, _ action:Selector) {
    let t = SingleTouchDownGestureRecognizer(target: self, action: action)
    v.addGestureRecognizer(t)
}

测试表明，它不会被调用一次以上。 它可以作为一个下拉更换; 你可以在两个电话之间只是交换。

Answer 2:

使用UILongPressGestureRecognizer并设置其minimumPressDuration 0它将期间像向下触摸UIGestureRecognizerStateBegan状态。

对于斯威夫特4

func setupTap() {
    let touchDown = UILongPressGestureRecognizer(target:self, action: #selector(didTouchDown))
    touchDown.minimumPressDuration = 0
    view.addGestureRecognizer(touchDown)
}

@objc func didTouchDown(gesture: UILongPressGestureRecognizer) {
    if gesture.state == .began {
        doSomething()
    }
}

对于Objective-C的

例：

-(void)setupLongPress
{
   self.longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(didLongPress:)];
   self.longPress.minimumPressDuration = 0;
   [self.view addGestureRecognizer:self.longPress];
}

-(void)didLongPress:(UILongPressGestureRecognizer *)gesture
{
   if (gesture.state == UIGestureRecognizerStateBegan){
      [self doSomething];
   }
}

Answer 3:

斯威夫特（没有子）

这是类似于雨燕版本罗布香菜的Objective-C的答案 。

这个想法是使用长按手势识别与minimumPressDuration设置为零，而不是使用敲击手势识别。 这是因为长按手势识别报道触摸开始事件，而敲击手势没有。

import UIKit
class ViewController: UIViewController {

    @IBOutlet weak var myView: UIView!

    override func viewDidLoad() {
        super.viewDidLoad()

        // Add "long" press gesture recognizer
        let tap = UILongPressGestureRecognizer(target: self, action: #selector(tapHandler))
        tap.minimumPressDuration = 0
        myView.addGestureRecognizer(tap)
    }

    // called by gesture recognizer
    @objc func tapHandler(gesture: UITapGestureRecognizer) {

        // handle touch down and touch up events separately
        if gesture.state == .began {
            // do something...
            print("tap down")
        } else if gesture.state == .ended { // optional for touch up event catching
            // do something else...
            print("tap up")
        }
    }
}

Answer 4:

这是另一种解决方案。 创建UIControl的子类。 你甚至可以在故事板使用它像UIView的，因为UIControl是UIView的子类。

class TouchHandlingView: UIControl {
}

而addTarget吧：

@IBOutlet weak var mainView: TouchHandlingView!
...

mainView.addTarget(self, action: "startAction:", forControlEvents: .TouchDown)
...

然后指定的动作将被称为像的UIButton：

func startAction(sender: AnyObject) {
    print("start")
}

文章来源: UITapGestureRecognizer - make it work on touch down, not touch up?