NSLayoutManager numberOfGlyphs总是显示0，迅速

Question

我试图创建一个多页PDF与UITextView在每一页与所需的属性文本。但是，当我遇到一个问题，一旦应用程序存档和分发通过TestFlight进行测试。

下面是我用来生成多页的示例代码，

var textStorage = NSTextStorage()
textStorage = NSTextStorage(attributedString: attString)

let layoutManager = NSLayoutManager()

textStorage.addLayoutManager(layoutManager)

var pageSize = CGRect(x: 44, y: 108, width: 507, height: 690)
var lastGlyph = 0

while lastGlyph < layoutManager.numberOfGlyphs {
     let textContainer = NSTextContainer()
     let background = UINib(nibName: "background", bundle: nil).instantiate(withOwner: nil, options: nil)[0]
     background.frame = pageRect
     textContainer.size = subsequentPageSize.size
     layoutManager.addTextContainer(textContainer)
     let textView = UITextView(frame: pageSize, textContainer: textContainer)
     pageSize.origin.x += pageSize.width
     background.addSubview(textView)
     context.beginPage()
     background.layer.render(in: UIGraphicsGetCurrentContext()!)

     lastGlyph = NSMaxRange(layoutManager.glyphRange(for: textContainer))
}

如果从Xcode构建时在模拟器或设备上运行，这是非常好的，但是一旦应用发布，layoutManager.numberOfGlyphs总是返回0，即使我打印()它显示的布局管理器，

    <NSLayoutManager: 0x7ff313c9f6d0>
    0 containers, text backing has 57 characters
    Currently holding 57 glyphs.
    Glyph tree contents:  57 characters, 57 glyphs, 1 nodes, 64 node bytes, 64 storage bytes, 128 total bytes, 2.25 bytes per character, 2.25 bytes per glyph
    Layout tree contents:  57 characters, 57 glyphs, 0 laid glyphs, 0 laid line fragments, 1 nodes, 64 node bytes, 0 storage bytes, 64 total bytes, 1.12 bytes per character, 1.12 bytes per glyph, 0.00 laid glyphs per laid line fragment, 0.00 bytes per laid line fragment'.

我是不是漏掉了一些愚蠢的东西，或者是不是有一个我不知道的bug？我无法为我的一生明白它为什么不起作用！

感谢你所能给予的帮助。

Answer 1

我最终在NSTextStorage子类注释中找到了一个解决方案，

--NSTextStorage类--实现了更改管理(通过NSTextStorage()和endEditing()方法)、属性验证、委托处理和布局管理通知。它没有实现的一个方面是管理实际的属性字符串存储，子类通过覆盖两个NSAttributedString原语来管理.

因此，我修改了我的代码，并将textStorage.beginEditing()和textStorage.endEditing()添加到整个序列的开头和结尾，如下所示，一旦项目实现并直接从Xcode构建到设备或模拟器，它就可以工作了。

var textStorage = NSTextStorage()
textStorage.beginEditing()
if attribString != nil {
    textStorage = NSTextStorage(attributedString: attribString)
} else {
    textStorage = NSTextStorage(string: string)
}

let layoutManager = NSLayoutManager()
textStorage.addLayoutManager(layoutManager)

var pageSize = CGRect(x: 44, y: 108, width: 507, height: 690)
var lastGlyph = 0
while lastGlyph < layoutManager.numberOfGlyphs {     
    let textContainer = NSTextContainer()     
    let background = UINib(nibName: "background", bundle: nil).instantiate(withOwner: nil, options: nil)[0]     
    background.frame = pageRect     
    textContainer.size = subsequentPageSize.size     
    layoutManager.addTextContainer(textContainer)     
    let textView = UITextView(frame: pageSize, textContainer: textContainer)     
    background.addSubview(textView)     
    context.beginPage()     
    background.layer.render(in: UIGraphicsGetCurrentContext()!)    
    lastGlyph = NSMaxRange(layoutManager.glyphRange(for: textContainer))
}
textStorage.endEditing()