iOS 检测 UIView 的点击和触摸

Question

我遇到了一个问题，即确定如何检测 UIView 被触碰和 UIView 被点击。当它被按下时，我希望 UIView 改变它的背景颜色。当它被触摸时，我希望 UIView 执行某些任务。我想知道如何解决这个问题。

-(void)viewDidLoad
{        
    UITapGestureRecognizer *dismissGestureRecognition = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleDismissDoubleTap:)];
    dismissGestureRecognition.numberOfTapsRequired = 1;
    [sectionDismissDoubleView addGestureRecognizer:dismissGestureRecognition];

    UITapGestureRecognizer *dismissGestureDownRecognition = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(dismissGestureDownRecognition:)];
    dismissGestureRecognition.numberOfTouchesRequired = 1;
    [sectionDismissDoubleView addGestureRecognizer:dismissGestureDownRecognition];
}

- (void)handleDismissDoubleTap:(UIGestureRecognizer*)tap {
    SettingsDismissDoubleViewController *settingsDouble = [[SettingsDismissDoubleViewController alloc] initWithNibName:@"SettingsDismissDoubleViewController" bundle:nil];
    [self.navigationController pushViewController:settingsDouble animated:YES];
}

- (void)dismissGestureDownRecognition:(UIGestureRecognizer*)tap {
    NSLog(@"Down");
}

Answer 1

首先，通过您的选择器handleDismissDoubleTap:，我假设您正在寻找双击关闭。为此，您应该这样做：dismissGestureRecognition.numberOfTapsRequired = 2;

其次，如果您所说的触摸是指长时间的点击（或“点击并按住”）手势，您应该使用UILongPressGestureRecognizer 而不是UITapGestureRecognizer。

Answer 2

在每个 UIControl 子类（UIButton 等）中，您都可以使用它来订阅一组特定的 UIControlEvent：

addTarget:action:forControlEvents

您应该为UIControLeventTouchDock和UIControLeventTouchUpInside事件的另一个目标/选择器添加目标。

UIControl reference

Answer 3

手势识别器可能对你想要的东西来说太过分了。您可能只想使用-touchesBegan:withEvent: 和-touchesEnded:withEvent: 的组合。

这是有缺陷的，但它应该让你知道你想做什么。

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    self.touchDown = YES;
    self.backgroundColor = [UIColor redColor];
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    // Triggered when touch is released
    if (self.isTouchDown) {
        self.backgroundColor = [UIColor whiteColor];
        self.touchDown = NO;
    }
}

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
    // Triggered if touch leaves view
    if (self.isTouchDown) {
        self.backgroundColor = [UIColor whiteColor];
        self.touchDown = NO;
    }
}

此代码应放入您创建的UIView 的自定义子类中。然后使用此自定义视图类型而不是 UIView，您将获得触摸处理。

Answer 4

感谢Holly's answer 我建立了一个ButtonView 便利类。

编辑：正如answer 所说，UILongPressGestureRecognizer 反应更快，所以我更新了我的课程。

用法：

let btn = ButtonView()
btn.onNormal = { btn.backgroundColor = .clearColor() }
btn.onPressed = { btn.backgroundColor = .blueColor() }
btn.onReleased = yourAction // Function to be called

类：

/** View that can be pressed like a button */

import UIKit

class ButtonView : UIView {

    /* Called when the view goes to normal state (set desired appearance) */
    var onNormal = {}
    /* Called when the view goes to pressed state (set desired appearance) */
    var onPressed = {}
    /* Called when the view is released (perform desired action) */
    var onReleased = {}

    override init(frame: CGRect)
    {
        super.init(frame: frame)

        let recognizer = UILongPressGestureRecognizer(target: self, action: Selector("touched:"))
        recognizer.delegate = self
        recognizer.minimumPressDuration = 0.0
        addGestureRecognizer(recognizer)
        userInteractionEnabled = true

        onNormal()
    }

    func touched(sender: UILongPressGestureRecognizer)
    {
        if sender.state == .Began {
            onPressed(self)
        } else if sender.state == .Ended {
            onNormal(self)
            onReleased()
        }
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

Answer 5

此方法不需要任何子类化。您只需将UILongPressGestureRecognizer 添加到视图并将minimumPressDuration 设置为零。然后检查调用手势事件时的状态以查看触摸事件是开始还是结束。

这是上面示例图片的整个项目代码。

import UIKit
class ViewController: UIViewController {
    @IBOutlet weak var myView: UIView!
    override func viewDidLoad() {
        super.viewDidLoad()
        let tap = UILongPressGestureRecognizer(target: self, action: #selector(tapHandler))
        tap.minimumPressDuration = 0
        myView.addGestureRecognizer(tap)
    }

    @objc func tapHandler(gesture: UITapGestureRecognizer) {
        
        // there are seven possible events which must be handled

        if gesture.state == .began {
            myView.backgroundColor = UIColor.darkGray
            return
        }

        if gesture.state == .changed {
            print("very likely, just that the finger wiggled around while the user was holding down the button. generally, just ignore this")
            return
        }

        if gesture.state == .possible || gesture.state == .recognized {
            print("in almost all cases, simply ignore these two, unless you are creating very unusual custom subclasses")
            return
        }

        // the three remaining states are
        // .cancelled, .failed, and .ended
        // in all three cases, must return to the normal button look:
        myView.backgroundColor = UIColor.lightGray
    }
}

感谢this answer 的创意。