Long press on one UITabBarItem

Question

I use a long click gesture on the tab bar. But I only need a long gesture of pressing for one tab element.

How can I solve this problem? Can I customize a long click gesture in the tab bar?

Answer 1

You can subclass UITabBarControllerand add UILongPressGestureRecognizerto it tabBar. Acting as a delegate of the gesture recognizer, you can choose when it detects a long print. As an element of the tab bar will be selected as soon as the user touches it, you can use the property selectedItemto perform this check.

@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 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

, 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 3

If you just need to recognize a long click on one of the tabBar elements, you can do this in the corresponding viewController method viewDidLoad:

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

And then:

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

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

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

This does not work if you just switch tabs.