swift - 当固定在 UINavigationBar 下方时，UISearchBar 没有居中

Question

下面是配置 View 约束的代码:

func configNavigationBarConstraints() {
    navigationBar.autoPinEdge(toSuperviewEdge: .leading)
    navigationBar.autoPinEdge(toSuperviewEdge: .trailing)
    if #available(iOS 11.0, *) {
        navigationBar.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor).isActive = true
        return
    }
    navigationBar.topAnchor.constraint(equalTo: topLayoutGuide.bottomAnchor).isActive = true
}

func configSearchBarConstraints() {
    searchBar.autoPinEdge(.top, to: .bottom, of: navigationBar)
    //    taskHistorySearchBar.autoPinEdge(.top, to: .bottom, of: navigationBar, withOffset: 6) //This is a solution but no ideal, the height diff varies by device
    searchBar.autoPinEdge(toSuperviewEdge: .left)
    searchBar.autoPinEdge(toSuperviewEdge: .right)
}

这会导致此 View :

请注意，UISearchBar 未对齐，知道我能做什么吗？即使我通过约束将其设置为具有较高的高度值，中心也会偏移。

Answer 1

您可能设置了 UINavigationBar 的委托(delegate)和 UISearchBar 的委托(delegate)，它们都扩展了 UIBarPositioningDelegate，所以您需要这样做:

extension ViewController: UINavigationBarDelegate {
  func position(for bar: UIBarPositioning) -> UIBarPosition {
    if bar is UINavigationBar {
      return .topAttached
    }
    return .any
  }
}

这只会应用 UINavigationBar 的 .topAttached 设置。