ios - previewController previewItemAt 未被调用。 iOS 10,swift 3,模拟器
<p><p>我在 Storyboard中创建了一个新的 ViewController 。将其连接到 ListViewController。 ListViewController 将正确的数据填入<code>aboutDict</code>。构建 <code>fileURLs[]</code> 并调用 <code>func numberOfPreviewItems(in: QLPreviewController) -> Int</code> - 调试器显示 <code>fileURLs[]</code> 为预期:</p>
<blockquote>
<p>Printing description of self.fileURLs: ▿ 1 element
- 0 : file:///Users/kent/Library/Developer/CoreSimulator/Devices/5E23825C-DF99-455A-BEB1-F73398E7759F/data/Containers/Bundle/Application/307ED7DF-C07C-4C0A-BA78-938BABE7C22C/WINSystemInfo.app/ID-51A_E_PLUS2.pdf`</p>
</blockquote>
<p>但是 <code>func previewController(_ controller: QLPreviewController, previewItemAt index: Int) -> QLPreviewItem</code> 和 <code>func previewController(_ controller: QLPreviewController, shouldOpen url: URL, for item: QLPreviewItem) -> Bool</code> 不被调用。</p>
<p>我得到了一个不错的 ViewController,它被插入导航堆栈,并带有正确的后退按钮名称,以及一个带有居中文本“没有要预览的文件”的灰色页面。</p>
<p>按下“返回”按钮时,会调用 <code>func previewControllerWillDismiss(_ controller: QLPreviewController)</code>。所以<em>一些</em>的委托(delegate)和数据源函数正在被调用。</p>
<p>我一定错过了一些简单的东西...... </p>
<p>我在下面附加了我的类 FileViewController.swift:</p>
<pre><code>class FileViewController: QLPreviewController, QLPreviewControllerDelegate, QLPreviewControllerDataSource {
var aboutDict = ()
// QuickLook data
var fileURLs = ()
// MARK: - Lifecycle
override func viewDidLoad() {
super.viewDidLoad()
let filename = aboutDict["filename"] as! String?
let filetype = aboutDict["filetype"] as! String?
title = aboutDict["title"] as! String?
dataSource = self
delegate = self
if let fileUrl = Bundle.main.url(forResource: filename, withExtension: filetype, subdirectory: nil, localization: nil)
{
let filePreview = fileUrl as QLPreviewItem
fileURLs.append(filePreview)
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Preview controller datasourcefunctions
func numberOfPreviewItems(in: QLPreviewController) -> Int {
return fileURLs.count
}
func previewController(_ controller: QLPreviewController, previewItemAt index: Int) -> QLPreviewItem {
return fileURLs
}
// MARK: - Preview controller delegate functions
func previewControllerWillDismiss(_ controller: QLPreviewController) {
debug("previewControllerWillDismiss")
}
func previewController(_ controller: QLPreviewController, shouldOpen url: URL, for item: QLPreviewItem) -> Bool {
return true
}
}
</code></pre>
<p>我错过了什么?</p>
<p>谢谢。</p></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>我刚遇到这个问题,只是因为我忘记在 QLPreviewController 上设置我的数据源...</p></p>
<p style="font-size: 20px;">关于ios - previewController previewItemAt 未被调用。 iOS 10,swift 3,模拟器,我们在Stack Overflow上找到一个类似的问题:
<a href="https://stackoverflow.com/questions/42711699/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/42711699/
</a>
</p>
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