实现 Accessibility - 无障碍功能

Author: Developer

BSText/Sources/Accessibility/BSTextAccessibility.swift

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+//
+//  BSTextAccessibility.swift
+//  BSText 3.0
+//
+//  Accessibility support for BSText components.
+//
+
+import UIKit
+
+/// Accessibility extensions for BSTextView.
+extension BSTextView {
+    
+    /// Configures accessibility settings for the text view.
+    public func configureAccessibility() {
+        isAccessibilityElement = true
+        accessibilityLabel = "Text editor"
+        accessibilityHint = "Double tap to edit"
+        accessibilityTraits = .staticText
+    }
+    
+    /// Updates accessibility label with current text content.
+    public func updateAccessibilityLabel() {
+        let textLength = text.count
+        if textLength > 0 {
+            let preview = text.prefix(50) + (textLength > 50 ? "..." : "")
+            accessibilityLabel = "\(preview) (\(textLength) characters)"
+        } else {
+            accessibilityLabel = "Empty text editor"
+        }
+    }
+    
+    /// Posts accessibility notification when text changes.
+    public func postTextChangeNotification() {
+        UIAccessibility.post(notification: .layoutChanged, argument: self)
+    }
+}
+
+/// Accessibility extensions for BSTextCodeEditor.
+extension BSTextCodeEditor {
+    
+    /// Configures accessibility settings for the code editor.
+    public override func configureAccessibility() {
+        isAccessibilityElement = true
+        accessibilityLabel = "Code editor"
+        accessibilityHint = "Double tap to edit code"
+        accessibilityTraits = .staticText
+    }
+}
+
+/// Accessibility container for text attachments.
+@objcMembers
+public class BSTextAttachmentAccessibilityElement: UIAccessibilityElement {
+    
+    /// The attachment this element represents.
+    public weak var attachment: BSTextAttachment?
+    
+    /// The text view containing this attachment.
+    public weak var textView: UIView?
+    
+    public init(accessibilityContainer: Any, attachment: BSTextAttachment, textView: UIView) {
+        super.init(accessibilityContainer: accessibilityContainer)
+        self.attachment = attachment
+        self.textView = textView
+        configure()
+    }
+    
+    private func configure() {
+        guard let attachment = attachment else {
+            accessibilityLabel = "Attachment"
+            accessibilityTraits = .staticText
+            return
+        }
+        
+        switch attachment.attachmentType {
+        case .image:
+            accessibilityLabel = "Image attachment"
+            accessibilityTraits = .image
+            
+        case .animatedImage:
+            accessibilityLabel = "Animated image"
+            accessibilityTraits = .image
+            
+        case .video:
+            accessibilityLabel = "Video attachment"
+            accessibilityTraits = .staticText
+            
+        case .view:
+            accessibilityLabel = "View attachment"
+            accessibilityTraits = .staticText
+            
+        case .swiftUI:
+            accessibilityLabel = "SwiftUI attachment"
+            accessibilityTraits = .staticText
+            
+        default:
+            accessibilityLabel = "Attachment"
+            accessibilityTraits = .staticText
+        }
+    }
+}
+
+/// Accessibility delegate for BSTextView.
+@objc public protocol BSTextAccessibilityDelegate: AnyObject {
+    
+    /// Called when accessibility element needs to be created for an attachment.
+    ///
+    /// - Parameters:
+    ///   - textView: The text view.
+    ///   - attachment: The attachment.
+    ///   - frame: The frame of the attachment.
+    /// - Returns: An accessibility element for the attachment.
+    @objc optional func textView(_ textView: BSTextView, accessibilityElementFor attachment: BSTextAttachment, frame: CGRect) -> BSTextAttachmentAccessibilityElement?
+}
+
+/// Accessibility helper for managing attachment accessibility.
+@objcMembers
+public class BSTextAccessibilityManager: NSObject {
+    
+    /// The text view being managed.
+    public weak var textView: BSTextView?
+    
+    /// Accessibility elements for attachments.
+    public private(set) var attachmentElements: [BSTextAttachmentAccessibilityElement] = []
+    
+    public init(textView: BSTextView) {
+        self.textView = textView
+        super.init()
+    }
+    
+    /// Updates accessibility elements for current attachments.
+    public func updateAccessibilityElements() {
+        attachmentElements.removeAll()
+        
+        guard let textView = textView else {
+            return
+        }
+        
+        let textStorage = textView.textStorage
+        textStorage.enumerateAttribute(.attachment, in: NSRange(location: 0, length: textStorage.length)) { value, range, _ in
+            if let attachment = value as? BSTextAttachment {
+                let element = BSTextAttachmentAccessibilityElement(
+                    accessibilityContainer: textView,
+                    attachment: attachment,
+                    textView: textView
+                )
+                attachmentElements.append(element)
+            }
+        }
+    }
+    
+    /// Returns all accessibility elements.
+    public func attachmentAccessibilityElements() -> [Any] {
+        return attachmentElements
+    }
+}
+
+/// Dynamic Type support extensions.
+extension BSTextView {
+    
+    /// Enables dynamic type support.
+    public func enableDynamicType() {
+        NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(handleContentSizeCategoryChange),
+            name: UIContentSizeCategory.didChangeNotification,
+            object: nil
+        )
+    }
+    
+    /// Disables dynamic type support.
+    public func disableDynamicType() {
+        NotificationCenter.default.removeObserver(
+            self,
+            name: UIContentSizeCategory.didChangeNotification,
+            object: nil
+        )
+    }
+    
+    @objc private func handleContentSizeCategoryChange() {
+        // Update font based on content size category
+        let preferredFont = UIFont.preferredFont(forTextStyle: .body)
+        font = preferredFont
+    }
+}