Question

我尝试将所选标签栏项的字体粗细设置为粗体字。它似乎没有效果。知道什么是错的。 forState: .Normal按预期工作，forState: .Selected无效。

let tabBarItem0 = tabBar.items![0] as! UITabBarItem
var selectedImage0 : UIImage = UIImage(named:"ic_tabbar_item_one")!.imageWithRenderingMode(UIImageRenderingMode.AlwaysOriginal)
var fontLight:UIFont = UIFont(name: "HelveticaNeue-UltraLight", size: 12)!
var fontBold:UIFont = UIFont(name: "HelveticaNeue-Bold", size: 12)!

tabBarItem0.image = unselectedImage0
tabBarItem0.selectedImage = selectedImage0
tabBarItem0.title = "Overview"
tabBarItem0.setTitleTextAttributes(
    [
        NSForegroundColorAttributeName: UIColor.whiteColor(),
        NSFontAttributeName: fontLight
    ], forState: .Normal)

tabBarItem0.setTitleTextAttributes(
    [
        NSForegroundColorAttributeName: UIColor.whiteColor(),
        NSFontAttributeName: fontBold
    ], forState: UIControlState.Selected)

Answer 1

找到解决方案（Swift 3，XCode 8.1）

在Storyboard中，为每个UITabBarItem提供一个唯一标记：对于每个标签 - ＆gt;选择它并转到它＆＃34;属性检查器＆＃34; - ＆GT;在＆＃34;标记＆＃34;中为每个人提供唯一号码。字段，但你不应该使用零（我使用1到4）。

这将我们设置为稍后，以确定按下哪个标签。

创建UITabBarController的新子类，然后分配：FILE - ＆gt;新文件 - ＆gt; iOS Cocoa Touch - ＆gt;创建UITabBarController的子类。将新的.swift文件分配给您的.swift文件＆＃34; Identity Inspector下的UITabBarController。＆＃34;

我们需要在UITabBarController中使用自定义逻辑。

创建UITabBarItem的新子类，将相同的文件分配给所有UITabBarItems ：FILE - ＆gt;新文件 - ＆gt; iOS Cocoa Touch - ＆gt;创建UITabBarItem的子类，并将相同的子类分配给所有选项卡。

我们的标签栏项目需要共享自定义逻辑。

将此代码添加到您的UITabBarItem子类，它会设置初始状态（主要标签粗体，其余未选中），并允许进行程序化标签更改：

class MyUITabBarItemSubclass: UITabBarItem {

    //choose initial state fonts and weights here
    let normalTitleFont = UIFont.systemFont(ofSize: 12, weight: UIFontWeightRegular) 
    let selectedTitleFont = UIFont.systemFont(ofSize: 12, weight: UIFontWeightBold)

    //choose initial state colors here
    let normalTitleColor = UIColor.gray 
    let selectedTitleColor = UIColor.black

    //assigns the proper initial state logic when each tab instantiates 
    override func awakeFromNib() {
        super.awakeFromNib()

        //this tag # should be your primary tab's Tag* 
        if self.tag == 1 { 
            self.setTitleTextAttributes([NSFontAttributeName: selectedTitleFont, NSForegroundColorAttributeName: selectedTitleColor], for: UIControlState.normal)
        } else {
            self.setTitleTextAttributes([NSFontAttributeName: normalTitleFont, NSForegroundColorAttributeName: normalTitleColor], for: UIControlState.normal)
        }

    }

}

在这里我们设置初始状态，以便在应用程序打开时正确设置选项卡，我们将在下一个子类中处理物理选项卡。

将此代码添加到您的UITabBarController子类，这是在按下选项卡时分配正确状态的逻辑。

class MyUITabBarControllerSubclass: UITabBarController {

    //choose normal and selected fonts here
    let normalTitleFont = UIFont.systemFont(ofSize: 12, weight: UIFontWeightRegular)
    let selectedTitleFont = UIFont.systemFont(ofSize: 12, weight: UIFontWeightBold)

    //choose normal and selected colors here
    let normalTitleColor = UIColor.gray
    let selectedTitleColor = UIColor.black


    //the following is a delegate method from the UITabBar protocol that's available 
    //to UITabBarController automatically. It sends us information every
    //time a tab is pressed. Since we Tagged our tabs earlier, we'll know which one was pressed,
    //and pass that identifier into a function to set our button states for us

    override func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem) {
        setButtonStates(itemTag: item.tag)
    }


    //the function takes the tabBar.tag as an Int
    func setButtonStates (itemTag: Int) {

        //making an array of all the tabs
        let tabs = self.tabBar.items

        //looping through and setting the states
        var x = 0
        while x < (tabs?.count)! {

            if tabs?[x].tag == itemTag {
                tabs?[x].setTitleTextAttributes([NSFontAttributeName: selectedTitleFont, NSForegroundColorAttributeName: selectedTitleColor], for: UIControlState.normal)
            } else {
                tabs?[x].setTitleTextAttributes([NSFontAttributeName: normalTitleFont, NSForegroundColorAttributeName: normalTitleColor], for: UIControlState.normal)
            }

            x += 1

        }

    }

}

看起来这是一种痛苦，因为由于某种原因，标签不会将状态变化识别为＆＃34; .Selected＆＃34;。我们必须通过仅使用.Normal状态来做所有事情 - 基本上自己检测状态变化。

您可以通过编程方式更改标签并仍然可以通过...检测状态更改。如果有人有兴趣，我稍后会更新，只需询问。

希望这有帮助！

Answer 2

问题是tabBarItem0的状态未更改为Selected。因为这是UITabBarItem，它代表UITabBar的单个元素。因此，您无法使用UITabBarItem API直接更改状态。您必须通过分配selectedItem来更改状态。

这些信息来自文档，我建议所有程序员都有这样的技能。希望这会有所帮助。

Answer 3

UITabBarItem.appearance().setTitleTextAttributes(
        [NSFontAttributeName: UIFont(name:"your_font_name", size:11)!, 
            NSForegroundColorAttributeName: UIColor(rgb: 0x929292)], 
        forState: .Normal)

Answer 4

要设置TitleTextAttribute，您应该使用appearance代理，例如：[UIBarItem appearance]

Answer 5

构建设置\快速语言版本：4.1

常规\部署目标：10.3

import UIKit

class FirstViewController: UIViewController {

  override func viewDidLoad() {
    super.viewDidLoad()

    let attrsNormal = [NSAttributedStringKey.foregroundColor : UIColor.black,
                 NSAttributedStringKey.font : UIFont(name: "Arial", size: 14)!]
    UITabBarItem.appearance().setTitleTextAttributes(attrsNormal,
                                                     for: UIControlState.normal)

    let attrsSelected = [NSAttributedStringKey.foregroundColor : UIColor.red,
                       NSAttributedStringKey.font : UIFont(name: "Arial", size: 14)!]
    UITabBarItem.appearance().setTitleTextAttributes(attrsSelected,
                                                     for: UIControlState.selected)
  }
  ...
}

Answer 6

当我尝试使用 UITabBarItem 更改所选选项卡的字体但它不起作用时。建议采用委托以在选项卡更改时获得通知。我只是拼凑起来。


private class MyTabBarController: UITabBarController {

    override func viewDidLoad() {
        super.viewDidLoad()
        delegate = self
    }

    override func setViewControllers(_ viewControllers: [UIViewController]?, animated: Bool) {
        super.setViewControllers(viewControllers, animated: animated)
        changeFontSelectedTab()
    }
}

extension MyTabBarController: UITabBarControllerDelegate {

    public func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) {
        changeFontSelectedTab()
    }

    func changeFontSelectedTab() {
        let normalLabelFont = UIFont.systemFont(ofSize: 18, weight: .regular)
        let selectedLabelFont = UIFont.systemFont(ofSize: 20, weight: .semibold)
        let labelColor = UIColor.init(red: 38/255.0, green: 38/255.0, blue: 38/255.0, alpha: 1.0)
        let selectedIconColor = UIColor.init(red: 8/255.0, green: 8/255.0, blue: 8/255.0, alpha: 1.0)

        viewControllers?.forEach {
            let selected = $0 == self.selectedViewController
            if selected {
                $0.tabBarController?.tabBar.tintColor = selectedIconColor
            }
            let selectFont =  (selected ? selectedLabelFont : normalLabelFont)
            $0.tabBarItem.setTitleTextAttributes([.font: selectFont, .foregroundColor: labelColor], for: .normal)
        }
    }
}

在Swift for iOS中将TabBarItem标题字体更改为粗体

6 个答案:

找到解决方案（Swift 3，XCode 8.1）