破碎的UIearchBar动画嵌入在NavigationItem中

Question

我遇到了将搜索栏添加到导航项的新方法的问题.

正如您在下图中所看到的,有两个UIViewControllers一个接一个,并且都有搜索栏.问题是动画,当搜索栏在第一个视图控制器上可见但在第二个视图控制器上不可见时,这很难看.搜索栏占用的区域停留在屏幕上并突然消失.

代码非常基本(项目中没有其他更改):

(我主要使用C#编写,因此此代码中可能存在错误.)

ViewController.swift:

import UIKit

class ViewController: UITableViewController, UISearchResultsUpdating {

override func loadView() {
    super.loadView()

    definesPresentationContext = true;

    navigationController?.navigationBar.prefersLargeTitles = true;
    navigationItem.largeTitleDisplayMode = .automatic;
    navigationItem.title = "VC"

    tableView.insetsContentViewsToSafeArea = true;
    tableView.dataSource = self;

    refreshControl = UIRefreshControl();
    refreshControl?.addTarget(self, action: #selector(ViewController.handleRefresh(_:)), for: UIControlEvents.valueChanged)
    tableView.refreshControl = refreshControl;

    let stvc = UITableViewController();
    stvc.tableView.dataSource = self;

    let sc = UISearchController(searchResultsController: stvc);
    sc.searchResultsUpdater = self;
    navigationItem.searchController = sc;
}

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    var cell = tableView.dequeueReusableCell(withIdentifier: "cell1");
    if (cell == nil) {
        cell = UITableViewCell(style: .default, reuseIdentifier: "cell1");
    }
    cell?.textLabel?.text = "cell " + String(indexPath.row);
    return cell!;
}

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return 20;
}

override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    let vc = ViewController();
    navigationController?.pushViewController(vc, animated: true);
}

@objc func handleRefresh(_ refreshControl: UIRefreshControl) {
    DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(2), execute: {
        refreshControl.endRefreshing();
    })
}

func updateSearchResults(for searchController: UISearchController) {
}
}

AppDelegate.swift:

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

var window: UIWindow?

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

    window = UIWindow(frame: UIScreen.main.bounds);
    window?.rootViewController = UINavigationController(rootViewController: ViewController());
    window?.makeKeyAndVisible();

    UINavigationBar.appearance().barTintColor = UIColor.red;

    return true
}
}

想法？

Answer 1

看起来Apple仍然需要在新的大型标题风格中使用UISearchBar.如果UIViewController你推到没有它的navigationItem.searchController设置,动画工作正常.当两个实例UIViewController都在searchController集之间导航时,您会遇到导航栏高度跳跃的问题.

您可以通过创建UISearchController每次viewDidAppear调用(而不是创建它loadView)并将其设置navigationItem.searchController为nil 来解决(解决)问题viewDidDisappear.

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

    DispatchQueue.main.async {
        let stvc = UITableViewController()
        stvc.tableView.dataSource = self

        let sc = UISearchController(searchResultsController: stvc)
        sc.searchResultsUpdater = self
        self.navigationItem.searchController = sc
    }
}

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

    self.navigationItem.searchController = nil
}

异步分派的原因是navigationItem.searchController在viewDidAppear方法中设置内联时会引发异常:

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Only one palette with a top boundary edge can be active outside of a transition. Current active palette is <_UINavigationControllerManagedSearchPalette: 0x7fad67117e80; frame = (0 116; 414 0); layer = <CALayer: 0x60400002c8e0>>'

我知道这只是一个解决方法,但希望这对你现在有所帮助,直到Apple解决这个问题,在两个视图控制器之间进行导航,这两个视图控制器都有UISearchController一套navigationItem.