如何在Xcode中调整search bar的scope titles字体大小以适配iPad？

这个问题我之前也碰到过，确实Storyboard里找不到直接调整scope titles字体的选项——因为SearchBar的scope bar本质是个隐藏的UISegmentedControl，系统没在界面编辑器里暴露它的字体设置。不过用代码处理起来很简单，给你两个实用的方案：

方案1：全局统一设置（适合整个应用的SearchBar都需要适配） #

如果希望所有SearchBar的scope titles在iPad上都用更大的字体，可以用UIAppearance来全局配置，这样不用逐个修改SearchBar：

Swift 代码 #

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    // 针对iPad设备单独设置
    if UIDevice.current.userInterfaceIdiom == .pad {
        UISegmentedControl.appearance(whenContainedInInstancesOf: [UISearchBar.self]).setTitleTextAttributes([
            NSAttributedString.Key.font: UIFont.systemFont(ofSize: 16) // 这里替换成你需要的字体大小
        ], for: .normal)
    }
    return true
}

Objective-C 代码 #

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) {
        [[UISegmentedControl appearanceWhenContainedInInstancesOfClasses:@[[UISearchBar class]]] setTitleTextAttributes:@{
            NSFontAttributeName: [UIFont systemFontOfSize:16]
        } forState:UIControlStateNormal];
    }
    return YES;
}

方案2：针对单个SearchBar设置（只修改特定的SearchBar） #

如果只想调整某一个SearchBar的scope titles字体，可以直接获取它内部的UISegmentedControl来修改：

Swift 代码 #

override func viewDidLoad() {
    super.viewDidLoad()
    // 假设你的SearchBar实例名为searchBar
    if let scopeBar = searchBar.scopeBar as? UISegmentedControl, UIDevice.current.userInterfaceIdiom == .pad {
        scopeBar.setTitleTextAttributes([
            NSAttributedString.Key.font: UIFont.systemFont(ofSize: 16)
        ], for: .normal)
    }
}

Objective-C 代码 #

- (void)viewDidLoad {
    [super viewDidLoad];
    // 假设你的SearchBar实例名为searchBar
    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) {
        UISegmentedControl *scopeBar = (UISegmentedControl *)self.searchBar.scopeBar;
        [scopeBar setTitleTextAttributes:@{
            NSFontAttributeName: [UIFont systemFontOfSize:16]
        } forState:UIControlStateNormal];
    }
}

这两个方案都很简便，你可以根据自己的需求选一个。测试的时候记得切换到iPad模拟器或者真机看看效果，字体大小可以根据你的UI设计调整~

内容的提问来源于stack exchange，提问作者itch