如何在UIActivityViewController模式下显示文件大小和类型

import UIKit

class CustomActivityItemProvider: UIActivityItemProvider {
    let fileURL: URL
    
    init(fileURL: URL) {
        self.fileURL = fileURL
        super.init(placeholderItem: fileURL)
    }
    
    override var item: Any {
        // 获取文件大小
        let fileAttributes = try? FileManager.default.attributesOfItem(atPath: fileURL.path)
        let fileSize = fileAttributes?[FileAttributeKey.size] as? UInt64 ?? 0
        
        // 获取文件类型
        let fileExtension = fileURL.pathExtension
        
        return "文件大小：\(fileSize) 字节\n文件类型：\(fileExtension)"
    }
}

func shareFile(fileURL: URL) {
    let activityItemProvider = CustomActivityItemProvider(fileURL: fileURL)
    let activityViewController = UIActivityViewController(activityItems: [activityItemProvider], applicationActivities: nil)
    
    // 可以设置排除的分享选项，例如排除AirDrop
    activityViewController.excludedActivityTypes = [UIActivity.ActivityType.airDrop]
    
    // 在iPad上，需要设置popoverPresentationController的sourceView和sourceRect属性
    activityViewController.popoverPresentationController?.sourceView = self.view
    activityViewController.popoverPresentationController?.sourceRect = self.view.bounds
    
    present(activityViewController, animated: true, completion: nil)
}

// 使用示例
let fileURL = URL(fileURLWithPath: "path/to/file")
shareFile(fileURL: fileURL)