Question

我已成功链接来自CollectionViewController - ＆gt;的委托方法。 MenuTableViewController - ＆gt; ListViewController。在ListViewController扩展程序中，我致电changeTitleView()，但它无效。但是，数据成功传递，因为print(title)正确打印传递的信息。如果从changeTitle()

中调用，ListViewController会正确执行

class ListViewController { 
  var navigationTitle: String?

  @objc func changeTitle(title: String) {
    let titleLabel = UILabel()
      let attributes: NSDictionary = [
        NSAttributedStringKey.font:UIFont(name: "HelveticaNeue", size: 20)!,
        NSAttributedStringKey.foregroundColor: UIColor(red: 0.1137, green: 0.1137, blue: 0.149, alpha: 0.8) /* #1d1d26 */,
        NSAttributedStringKey.kern:CGFloat(2.0)
      ]

      let attributedTitle = NSAttributedString(string: 
      title.uppercased(), attributes: attributes as? [NSAttributedStringKey : AnyObject])
      titleLabel.attributedText = attributedTitle
      titleLabel.sizeToFit()
      self.navigationItem.titleView = titleLabel
   }
}

extension ListViewController: HandleTitleView {
  @objc func changeTitleView(title: String) {
    print(title)
    self.navigationTitle = title

    changeTitle(title: navigationTitle!)
}

其他信息：

1）我通过SWRevealController传递信息，因此并非所有数据都在同一个导航堆栈中。 ListViewController位于MenuTableViewController之上，CollectionViewController已从MenuTableViewController实例化，然后被解除

2）我在ListViewController创建了一个调用changeTitle()的按钮，它成功更改了navigationItem.titleView，因此我知道该方法有效。

提前致谢

Answer 1

你有没有试过以下

class ListViewController { 
      var navigationTitle: String? {
           didSet{
              if(navigationTitle != nil) {
                  changeTitle(title: navigationTitle!)
              }
           }
      }
      @objc func changeTitle(title: String) { 
         let titleLabel = UILabel() 
         let attributes: NSDictionary = [ NSAttributedStringKey.font:UIFont(name: "HelveticaNeue", size: 20)!, NSAttributedStringKey.foregroundColor: UIColor(red: 0.1137, green: 0.1137, blue: 0.149, alpha: 0.8) /* #1d1d26 */, NSAttributedStringKey.kern:CGFloat(2.0) ] 
         let attributedTitle = NSAttributedString(string: title.uppercased(), attributes: attributes as? [NSAttributedStringKey : AnyObject]) 
         titleLabel.attributedText = attributedTitle titleLabel.sizeToFit() 
         self.navigationItem.titleView = titleLabel 
    } 
} 
extension ListViewController: HandleTitleView { 
  @objc func changeTitleView(title: String) { 
    print(title) 
    self.navigationTitle = title
    // changeTitle(title: navigationTitle!) 
}`

Answer 2

  @objc func changeTitle(title: String) {
    let titleLabel = UILabel()
    let attributeFontSaySomething : [String : Any] = [NSFontAttributeName : UIFont(name: "HelveticaNeue", size: 20) ?? UIFont.systemFont(ofSize: 20) ,NSForegroundColorAttributeName :UIColor(red: 0.1137, green: 0.1137, blue: 0.149, alpha: 0.8),NSKernAttributeName : CGFloat(2.0) ]

    var attributes = attributeFontSaySomething

    let attStringSaySomething = NSAttributedString(string: title.uppercased(), attributes: attributes)

    titleLabel.attributedText = attStringSaySomething
    titleLabel.sizeToFit()
    self.navigationItem.titleView = titleLabel
}

您可以从此链接下载代码

Link

被调用的方法，但没有正确执行

2 个答案: