实现App国际化时，如何保留UILabel的自定义字体？

Hey there! Let’s tackle your localization + custom UILabel font questions step by step—this is a common scenario, and there are straightforward ways to keep your fonts intact while making your app multilingual.

First, let’s clarify: localization and font settings are separate concerns, so you don’t have to worry about localization overriding your fonts by default. Here’s how to handle both your Storyboard and code-based labels:

Storyboard-Based UILabels #

• When you localize your Storyboard (generating .storyboardstrings files for each language), these files only control the text content of your labels—not their font, color, or layout properties.
• Just set your custom font directly in the Storyboard’s Attributes Inspector, then update the corresponding entry in your .storyboardstrings file (e.g., "fxV-9K-0dL.text" = "Bonjour!";). The font you set in the Storyboard will stay applied automatically.

Code-Based UILabels #

For labels you create or reference in Swift code:

1. First, set your custom font as you normally would:

   myCustomLabel.font = UIFont(name: "YourCustomFont-Regular", size: 16)
   

2. Then assign the localized text using NSLocalizedString:

   myCustomLabel.text = NSLocalizedString("greeting_message", comment: "Main screen welcome text")
   

The font property is independent of the text content, so replacing the text with a localized string won’t touch your font settings.

To streamline this process (and avoid repeating NSLocalizedString calls everywhere), create a reusable UILabel subclass that handles both localization and custom fonts out of the box. This is the cleanest approach for larger apps or if you have many custom labels.

Here’s a complete implementation:

import UIKit

class LocalizedCustomFontLabel: UILabel {
    // IBInspectable lets you set these properties directly in Storyboard
    @IBInspectable var localizationKey: String? {
        didSet {
            updateLocalizedText()
        }
    }
    
    @IBInspectable var customFontName: String = "YourDefaultCustomFont" {
        didSet {
            updateFont()
        }
    }
    
    @IBInspectable var customFontSize: CGFloat = 16 {
        didSet {
            updateFont()
        }
    }
    
    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialize font and localized text when the label loads from Storyboard
        updateFont()
        updateLocalizedText()
    }
    
    private func updateLocalizedText() {
        guard let key = localizationKey else { return }
        text = NSLocalizedString(key, comment: "Localized text for key: \(key)")
    }
    
    private func updateFont() {
        // Fall back to system font if custom font isn't found
        let desiredFont = UIFont(name: customFontName, size: customFontSize) ?? UIFont.systemFont(ofSize: customFontSize)
        font = desiredFont
        
        // Optional: Support dynamic type (adjusts with system font size)
        adjustsFontForContentSizeCategory = true
        font = UIFontMetrics(forTextStyle: .body).scaledFont(for: desiredFont)
    }
}

How to Use This Subclass #

In Storyboard:

1. Add a UILabel to your view, then set its class to LocalizedCustomFontLabel in the Identity Inspector.
2. In the Attributes Inspector, you’ll see new fields:
   • Localization Key: Enter the key from your Localizable.strings file.
   • Custom Font Name: Type the exact name of your custom font (check your Info.plist or use UIFont.familyNames() to verify).
   • Custom Font Size: Set your desired font size.
3. That’s it—no code needed! The label will automatically load the localized text and apply your custom font.

In Code:

let welcomeLabel = LocalizedCustomFontLabel()
welcomeLabel.localizationKey = "welcome_message"
welcomeLabel.customFontName = "YourCustomFont-Bold"
welcomeLabel.customFontSize = 18
// Add constraints and add to view as usual
view.addSubview(welcomeLabel)

• Make sure your custom fonts are properly added to your project: include them in your target, and add their filenames to the Fonts provided by application array in your Info.plist.
• If you need different text styles (e.g., body, headline), adjust the UIFontMetrics text style in the updateFont() method to match your needs.

内容的提问来源于stack exchange，提问作者Ben