ios - 如何使用 url 而不是本地加载 rtf

Question

我有代码可以在textview中加载本地rtf文件，但如何使其适用于在线文件

因为当我使用 url 时它不起作用这是网址 - http://howtotechworld.com/rtfdoc.rtf

这是代码

  if let rtf = NSBundle.mainBundle().URLForResource("http://howtotechworld.com/rtfdoc", withExtension: "rtf", subdirectory: nil, localization: nil) {
  do {
            let attributedString = try NSAttributedString(fileURL: rtf, options: [NSDocumentTypeDocumentAttribute:NSRTFTextDocumentType], documentAttributes: nil)
            textView.attributedText = attributedString
            textView.editable = false
            print(attributedString)
   }
   catch _ {
            NSLog("catched a error");
   }

Answer 1

您应该异步下载 rtf 数据并使用 NSAttributedString 初始化器 init(data: NSData, options: [String : AnyObject], documentAttributes dict: AutoreleasingUnsafeMutablePointer<NSDictionary?>) throws完成后加载数据:

// your web link
let rtfLink  = "http://www.aliectronics.com.au/thefournobletruths.rtf"
// make sure your link is valid NSURL using guard  
guard let rtfURL = NSURL(string: rtfLink ) else { return }
// creata a data task for your url
NSURLSession.sharedSession().dataTaskWithURL(rtfURL) {
    (data, response, error) in
    // use guard to make sure you get a valid response from the server and your data it is not nil and you got no errors otherwise return 
    guard
        let httpURLResponse = response as? NSHTTPURLResponse where httpURLResponse.statusCode == 200,
        let data = data where error == nil
    else { return }
    // you need to use dispatch async to update the UI
    dispatch_async(dispatch_get_main_queue(), { () -> Void in
        // NSAttributedString data initialiser throws an error so you need to implement Swift2 Do Try Catch error handling
        do {
            let attributedString = try NSAttributedString(data: data, options: [NSDocumentTypeDocumentAttribute : NSRTFTextDocumentType], documentAttributes: nil)
            textView.attributedText = attributedString
            textView.editable = false
            print("attributedString=====start")
            print(attributedString)
            print("attributedString=====end")
        } catch let error as NSError {
            print(error.localizedDescription)
        }
    })
}.resume()