Question

我使用分段控件作为标签栏控制器的子标签。我在主选项卡上有一个按钮，它应该转换到第二个选项卡（带有子选项卡的选项卡），并以编程方式将UISegmentedControl切换到第一个选项卡（0索引）。

当然，点击分段控件可以正常工作。但是，当我尝试使用selectedSegmentIndex以编程方式更改选项卡时，取消选中的选项卡不会更新它的字体颜色，这会使标签看起来消失。

我读过的每篇关于如何以编程方式更改标签的帖子表明我正在以正确的方式进行。谁能告诉我我做错了什么？谢谢你的帮助！

以下是代码：

class AdvertisingViewController: BaseViewController, TabbedController, ClientSelectorController {

  var clientSelectorView: ClientSelector?
  var tabControl: UISegmentedControl!
  var tabView: UIView!
  var nextTabIndex: Int? = nil
  var activeTab: AdvertisingTabContent? = nil
  var tabs: [AdvertisingTabContent]!
  let margin: CGFloat = 20

  override func viewDidLoad() {
    super.viewDidLoad()

    // Initialize the tab view.
    tabView = UIView()
    view.addSubview(tabView!)

    // Initialize the tab controls.
    tabControl = UISegmentedControl()
    tabControl.insertSegment(withTitle: "Calendar", at: 0, animated: false)
    tabControl.insertSegment(withTitle: "TV", at: 1, animated: false)
    tabControl.insertSegment(withTitle: "Radio", at: 2, animated: false)
    tabControl.insertSegment(withTitle: "Search", at: 3, animated: false)
    tabControl.insertSegment(withTitle: "Display", at: 4, animated: false)
    tabControl.selectedSegmentIndex = 0
    tabControl.addTarget(self, action: #selector(selectedTab(sender:)), for: .valueChanged)
    view.addSubview(tabControl!)

    // Tab control styles.
    let font = UIFont.systemFont(ofSize: 12)
    tabControl.setTitleTextAttributes([
      NSAttributedStringKey.font: font,
      NSAttributedStringKey.foregroundColor: Color.lightGrey
    ], for: .normal)
    tabControl.removeBorders()

    // Intialize the tabs.
    nextTabIndex = nil
    tabs = [
      CampaignsTab(view: tabView),
      TVTab(view: tabView),
      RadioTab(view: tabView),
      PaidSearchTab(view: tabView),
      DisplayTab(view: tabView),
    ]

    // Bind clientSelector button to clientSelectButtonPressed method.
    initializeClientSelector()

    // Set the background color.
    tabView.backgroundColor = Color.backgroundColor
  }

  override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    // Update client selector title.
    layoutClientSelector()

    // Update tab view & segmented control
    let controlHeight: CGFloat = 35
    tabControl.frame = CGRect(x: margin, y: clientSelectorView!.frame.height, width: view.frame.width - (margin * 2), height: controlHeight)

    // Update the tab view.
    tabView.frame = CGRect(x: 0, y: clientSelectorView!.frame.height + controlHeight + margin, width: view.frame.width, height: view.frame.height - clientSelectorView!.frame.height - controlHeight - margin)

    // Build tab.
    buildTab()
  }

  override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)

    // Update the tabControl.
    if let next = nextTabIndex {
      if next != tabControl.selectedSegmentIndex {
        tabControl.selectedSegmentIndex = next
      }
      nextTabIndex = nil
    }
  }

  func clientSelectorClicked(selectorModal: UIViewController) {
    present(selectorModal, animated: true, completion: nil)
  }

  // MARK: - Tabs Control

  /**
   The user selected a different tab.
   */
  @objc func selectedTab(sender: UIButton) {
    buildTab()
  }

  /**
   A tab was selected from another part of the app.
   (This is called before viewWillAppear from another tab)
   */
  func switchToTab(atIndex index: Int) {
    nextTabIndex = index
  }

  func buildTab() {

    // Clean up the old tab.
    activeTab?.cleanUp()
    activeTab = nil

    // Check next index.
    var index = tabControl.selectedSegmentIndex
    if let next = nextTabIndex {
      index = next
    }

    // Add/Build the new tab.
    if index >= 0 && tabs.count > index {
      activeTab = tabs[index]
      activeTab?.buildViews()
    }
  }
}

更新

今天早上花了几个小时寻找解决方案。我还尝试通过在分段控件的子视图中找到标签并手动更改字体颜色来进行黑客攻击。我可以更改标签的文本，但不能更改字体颜色。有些东西凌驾于它之上。

是否有其他方式以编程方式更改所选索引？我需要向苹果提交门票吗？没有其他人有这个问题吗？提前感谢您提供的任何帮助。

Answer 1

经过多次挣扎，我终于找到了答案。我使用以下帖子中的方法删除边框：

Swift: How to remove border from segmented control

extension UISegmentedControl {
  func applyAppStyles() {
    setBackgroundImage(imageWithColor(color: Color.contentBackgroundColor), for: .normal, barMetrics: .default)
    setBackgroundImage(imageWithColor(color: Color.orange), for: .selected, barMetrics: .default)
    setDividerImage(imageWithColor(color: UIColor.clear), forLeftSegmentState: .normal, rightSegmentState: .normal, barMetrics: .default)
  }

  // create a 1x1 image with this color
  private func imageWithColor(color: UIColor) -> UIImage {
    let rect = CGRect(x: 0.0, y: 0.0, width:  1.0, height: 1.0)
    UIGraphicsBeginImageContext(rect.size)
    let context = UIGraphicsGetCurrentContext()
    context!.setFillColor(color.cgColor);
    context!.fill(rect);
    let image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image!
  }
}

我第一次打电话给setBackgroundImage导致了这个问题;我不确定为什么。但是以下代码修复了它：

tabControl.setTitleTextAttributes([
  NSAttributedStringKey.foregroundColor: Color.darkGreyBlue
], for: .selected)

以编程方式更新UISegmentControl不会更新未选定的段

1 个答案: