Changing selected TabBarItem font iOS

问题

I have a TabBar. I am trying to style it so that the titles on the TabBarItems have different fonts for the normal state and the selected state. For normal state I want Helvetica Neue Light and for the selected state I want Helvetica Neue Medium. No matter what I do, I can't seem to get the fonts to be different for these two states. The color changing works fine. Here is what I currently have:

  // Set the tab bar title appearance for normal state.
  [[UITabBarItem appearance] setTitleTextAttributes:@{
     NSFontAttributeName: [UIFont fontWithName:@"HelveticaNeue-Light"
                                          size:16],
     NSForegroundColorAttributeName: [CMK8Colors grayColor]
   }
                                           forState:UIControlStateNormal];

  // Set the tab bar title appearance for selected state.
  [[UITabBarItem appearance] setTitleTextAttributes:@{
     NSFontAttributeName: [UIFont fontWithName:@"HelveticaNeue-Medium"
                                          size:16],
     NSForegroundColorAttributeName: [CMK8Colors blueColor]
   }
                                           forState:UIControlStateSelected];

Please help.

回答1:

Good news and bad news.

Bad news, It's a little harder than just using the appearance proxy.

Good news It's not that much harder!

Header

#import <UIKit/UIKit.h>

@interface MYTabbyViewController : UITabBarController

@end

Implementation

#import "MYTabbyViewController.h"

@implementation MYTabbyViewController

-(void)setSelectedViewController:(UIViewController *)selectedViewController
{
    [super setSelectedViewController:selectedViewController];

    for (UIViewController *viewController in self.viewControllers) {
        if (viewController == selectedViewController) {
            [viewController.tabBarItem setTitleTextAttributes:@{
                                                    NSFontAttributeName: [UIFont fontWithName:@"HelveticaNeue-Medium" size:16],
                                                    NSForegroundColorAttributeName: [UIColor blueColor]
                                                    }
                                         forState:UIControlStateNormal];
        } else {
            [viewController.tabBarItem setTitleTextAttributes:@{
                                                    NSFontAttributeName: [UIFont fontWithName:@"HelveticaNeue-Light" size:16],
                                                    NSForegroundColorAttributeName: [UIColor grayColor]
                                                    }
                                         forState:UIControlStateNormal];
        }
    }
}

The last part you will need is to use this subclass instead of the out-of-the-box UITabBarController. If you are using Storyboards, simply select the TabBarController, go to the Identity Inspector (third subtab in the right panel) and change UITabBarController to MYTabBarController or what have you.

But yeah! Bottom line, just update the ViewController tabBarItem!

回答2:

@Acey´s answer in Swift 3:

    override var selectedViewController: UIViewController? {
    didSet {

        guard let viewControllers = viewControllers else {
            return
        }

        for viewController in viewControllers {

            if viewController == selectedViewController {

                let selected: [String: AnyObject] =
                    [NSFontAttributeName: UIFont.systemFont(ofSize: 11, weight: UIFontWeightHeavy),
                     NSForegroundColorAttributeName: UIColor.red]

                viewController.tabBarItem.setTitleTextAttributes(selected, for: .normal)

            } else {

                let normal: [String: AnyObject] =
                    [NSFontAttributeName: UIFont.systemFont(ofSize: 11),
                     NSForegroundColorAttributeName: UIColor.blue]

                viewController.tabBarItem.setTitleTextAttributes(normal, for: .normal)

            }
        }
    }
}

回答3:

@Acey's Answer is almost perfect, but only change the font after your first selection of a tabBarItem, so when the tabBar is created, it will be created with no different font for the selected tabBarItem in that moment. To achieve that i also add a didSet in selectedIndex variable.

Here's the Complete code (Swift 4.2)

final class TabBarController: UITabBarController {

override var selectedIndex: Int {
    didSet {
        guard let selectedViewController = viewControllers?[selectedIndex] else {
            return
        }
        selectedViewController.tabBarItem.setTitleTextAttributes([.font: UIFont.systemFont(ofSize: 11, weight: UIFontWeightHeavy)], for: .normal)
    }
}

override var selectedViewController: UIViewController? {
    didSet {

        guard let viewControllers = viewControllers else {
            return
        }

        for viewController in viewControllers {

            if viewController == selectedViewController {

                let selected: [NSAttributedString.Key: AnyObject] =
                    [.font: UIFont.systemFont(ofSize: 11, weight: UIFontWeightHeavy)]

                viewController.tabBarItem.setTitleTextAttributes(selected, for: .normal)

            } else {

                let normal: [NSAttributedString.Key: AnyObject] =
                    [.font: UIFont.systemFont(ofSize: 11)]

                viewController.tabBarItem.setTitleTextAttributes(normal, for: .normal)

            }
        }
    }
}

}

回答4:

setSelected and setHighlighted does not work for UIBarButtonItems.

Use UIBarButtonItem's

- (void)setBackgroundImage:(UIImage *)backgroundImage forState:(UIControlState)state barMetrics:(UIBarMetrics)barMetrics 

Here is the documentation - https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIBarButtonItem_Class/Reference/Reference.html

Alternatively, use UIButton.

UIButton *myButton = [UIButton buttonWithType: UIButtonTypeRoundedRect];
[myButton setTitle:@"Info" forState:UIControlStateNormal];
[myButton setFont:[UIFont fontWithName:<font name> size:<font size>]];

[myButton setTitleColor:<color>;
myButton =  <frame>;
[myButton addTarget:self.webView action:@selector(<action>:) forControlEvents:UIControlEventTouchUpInside];
UIBarButtonItem * barButtonItem = [[UIBarButtonItem alloc]initWithCustomView:myButton];
[[UIBarButtonItem appearance] setTintColor:<color>;
[self.toolbar setItems:[NSArray arrayWithObjects: spaceItem, barButtonItem, nil]];

来源：https://stackoverflow.com/questions/25234671/changing-selected-tabbaritem-font-ios