处理单个 UITabBarItem 上的长按

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？我可以自定义标签栏中的长按手势吗？

Answer 1

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

@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

如果您只需要识别对其中一个 tabBar 项的长按，您可以在相应的 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();
        }
    }
}

如果你只是切换标签页，这不会触发。

Answer 3

下面是我如何使用 Swift 3:

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 4

我通过获取用户可以交互的特定 tabBarItem 视图并简单地向其添加长按手势来做到这一点。通过这种方式，您不必编写任何协议或将 TabBarViewController 子类化。

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({[=11=].isUserInteractionEnabled})
    return interactionViews.sorted(by: {[=11=].frame.minX < .frame.minX})
}

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

Answer 5

这是 swift 5 中的一个解决方案：使用故事板或代码将长按手势识别器添加到 "Entire" 标签栏。并且不要忘记让你的 ViewController 成为它的委托 .. 并实现下面的委托方法检查传入触摸是否在标签栏子视图的 "one" 内.. 如果是 return true , else return false .. 以下是仅当我们在第一个选项卡上长按时才会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数组计数是项目数 + 1，这是标签栏的背景..所以如果你想要第一个项目的视图，你可以找到它并且索引 1 而不是 0

处理单个 UITabBarItem 上的长按

Handle long press on a single UITabBarItem

objective-c

uigesturerecognizer

uitabbar

uilongpressgesturerecogni