Question

我在标签栏上使用长按手势。但我只需要一个特定标签栏项目的长按手势。

我该如何解决这个问题？我可以在标签栏中自定义长按手势吗？

Answer 1

您可以继承UITabBarController并向其UILongPressGestureRecognizer添加tabBar。作为手势识别器的代表，您可以选择何时检测到长按。由于标签栏项目会在用户触摸后立即被选中，因此您可以使用selectedItem属性执行此检查。

@interface TabBarController () <UIGestureRecognizerDelegate>
@property (nonatomic, strong) UILongPressGestureRecognizer *longPressRecognizer;

@end

@implementation TabBarController

- (void)viewDidLoad {
    [super viewDidLoad];

    self.longPressRecognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(recognizerFired:)];
    self.longPressRecognizer.delegate = self;
    [self.tabBar addGestureRecognizer:self.longPressRecognizer];
}

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {

    // This will ensure the long press only occurs for the
    // tab bar item which has it's tag set to 1.
    // You can set this in Interface Builder or in code
    // wherever you are creating your tabs.
    if (self.tabBar.selectedItem.tag == 1) {
        return YES;
    }
    else {
        return NO;
    }

}

- (void)recognizerFired:(UILongPressGestureRecognizer *)recognizer {
    // Handle the long press...
}

@end

Answer 2

以下是我使用Swift 3的方式：

protocol MyTabControllerProtocol: class {
    func tabLongPressed()
}

class MyTabController: UITabBarController {
    func viewDidLoad() {
        super.viewDidLoad()

        viewControllers = [
            // add your view controllers for each tab bar item
            // NOTE: if you want view controller to respond to long press, then it should extend MyTabControllerProtocol
        ]

        let longPressRecognizer = UILongPressGestureRecognizer(target: self, action: #selector(astroButtonItemLongPressed(_:)))
        tabBar.addGestureRecognizer(longPressRecognizer)
    }

    func astroButtonItemLongPressed(_ recognizer: UILongPressGestureRecognizer) {
        guard recognizer.state == .began else { return }
        guard let tabBar = recognizer.view as? UITabBar else { return }
        guard let tabBarItems = tabBar.items else { return }
        guard let viewControllers = viewControllers else { return }
        guard tabBarItems.count == viewControllers.count else { return }

        let loc = recognizer.location(in: tabBar)

        for (index, item) in tabBarItems.enumerated() {
            guard let view = item.value(forKey: "view") as? UIView else { continue }
            guard view.frame.contains(loc) else { continue }

            if let nc = viewControllers[index] as? UINavigationController {
                if let vc = nc.viewControllers.first as? MyTabControllerProtocol {
                    vc.tabLongPressed()
                }
            } else if let vc = viewControllers[index] as? MyTabControllerProtocol {
                vc.tabLongPressed()
            }

            break
        }
    }
}

Answer 3

如果你只需要识别其中一个tabBar项目的长按，你可以在相应的viewController的viewDidLoad方法中执行此操作：

UILongPressGestureRecognizer *longPressGesture = [[UILongPressGestureRecognizer alloc] initWithTarget: self action: @selector(handleLongPress:)];
[self.tabBarController.tabBar addGestureRecognizer: longPressGesture];

然后：

- (void)handleLongPress:(UILongPressGestureRecognizer *) recognizer {
    if (recognizer.state == UIGestureRecognizerStateBegan) {

        UITabBar *tabBar = ((UITabBar* )recognizer.view);

        if (tabBar.selectedItem == self.tabBarItem) {
            doSomethingVeryExciting();
        }
    }
}

如果您只是切换标签，则不会触发。

Answer 4

我通过获取用户可以交互的特定tabBarItem的视图并向其中添加长按手势来做到这一点。这样，您不必编写任何协议或TabBarViewController的子类。

let longPressGestureRecognizer = UILongPressGestureRecognizer.init(target: self, action: #selector(longTap(_:)))
    longPressGestureRecognizer.minimumPressDuration = 1.0
    self.tabBarController?.orderedTabBarItemViews()[0].addGestureRecognizer(longPressGestureRecognizer)

关于获取tabBarItemViews：

extension UITabBarController {
func orderedTabBarItemViews() -> [UIView] {
    let interactionViews = tabBar.subviews.filter({$0.isUserInteractionEnabled})
    return interactionViews.sorted(by: {$0.frame.minX < $1.frame.minX})
}

P.S。：viewController，即“ self”是tabBarController的第一项。

Answer 5

这是快速解决方案5：使用情节提要或代码将longpress手势识别器添加到“整个”选项卡中。并且不要忘了让您的ViewController作为其委托..并实现下面的委托方法检查传入的触摸是否在选项卡子视图的“一个”内部。如果是，则返回true，否则返回false。以下是仅在我们长按第一个标签时才让识别器触发的代码：

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {

    if touch.view?.isDescendant(of: tabBar.subviews[1]) == true {return true}
    return false



}

注意：tabbar.subviews数组计数是项目的数量+ 1，它是Tabbar的背景..因此，如果要查看第一个项目的视图，则可以将其命名为1而不是0

处理单个UITabBarItem上的长按

5 个答案: