Tab Bar和UISearchController提供黑屏

Question

我有兩個場景可以通過標簽欄訪問，在場景1有一個搜索欄。 我面臨的問題是，在搜索時是否切換到下載選項卡 -

1. 導航欄消失。
2. 當我回到搜索標簽時，它會給我一個黑屏。

這是搜索時的屏幕1 -

現在，當我單擊下載選項卡時，導航欄將消失。

這是第一個屏幕的視圖控制器 -

import UIKit
import Alamofire
import SwiftyJSON

class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, UISearchResultsUpdating, UISearchBarDelegate{

    //MARK: Variables
    var papers = [Paper]()
    var filteredPapers = [Paper]()
    let searchController = UISearchController(searchResultsController: nil)

    // MARK: Outlets
    @IBOutlet weak var activityIndicator: UIActivityIndicatorView!
    @IBOutlet var table: UITableView!
    @IBOutlet weak var loadingMessageLabel: UILabel!
    @IBOutlet weak var retryButton: UIButton!

    //MARK: Actions
    @IBAction func retryButton(sender: UIButton) {
        self.loadingMessageLabel.hidden = false
        self.loadingMessageLabel.text = "While the satellite moves into position..."
        self.activityIndicator.hidden = false
        self.activityIndicator.startAnimating()
        self.retryButton.hidden = true
        self.getPapersData()

    }

    // MARK: Table View

    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        // If in searching mode, then return the number of results else return the total number
//        if searchController.active && searchController.searchBar.text != "" {
        if searchController.active {
            return filteredPapers.count
        }
        return papers.count
    }

    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

        let paper: Paper

//        if searchController.active && searchController.searchBar.text != "" {
        if searchController.active {
            paper = filteredPapers[indexPath.row]
        } else {
            paper = papers[indexPath.row]
        }

        if let cell = self.table.dequeueReusableCellWithIdentifier("Cell") as? PapersTableCell {

            cell.initCell(paper.name, detail: paper.detail)
            print(cell)
            return cell
        }

        return PapersTableCell()

    }

    func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    }

    func tableView(tableView: UITableView, editActionsForRowAtIndexPath indexPath: NSIndexPath) -> [UITableViewRowAction]? {


        let downloadButton = UITableViewRowAction(style: .Normal, title: "Download") { action, index in

            var url = String(self.papers[indexPath.row].url)
            url = url.stringByReplacingOccurrencesOfString(" ", withString: "%20")
            print(url)
            let destination = Alamofire.Request.suggestedDownloadDestination(directory: .DocumentDirectory, domain: .UserDomainMask)

            // Spinner in cell

            //            var selectCell = self.table.cellForRowAtIndexPath(indexPath) as? PapersTableCell
            //            selectCell!.downloadSpinner.hidden = false

            // Dismiss the download button
            self.table.editing = false

            Alamofire.download(.GET, url, destination: destination).response { _, _, _, error in
                if let error = error {
                    print("Failed with error: \(error)")
                } else {
                    print("Downloaded file successfully")
                }
                //                selectCell?.downloadSpinner.hidden = true
            }

        }

        downloadButton.backgroundColor = UIColor(red:0.30, green:0.85, blue:0.39, alpha:1.0)


        return [downloadButton]

    }

    func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool {
        // the cells you would like the actions to appear needs to be editable
        return true
    }

    func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
        // you need to implement this method too or you can't swipe to display the actions
    }

    // MARK: Search

    func filterContentForSearchText(searchText: String, scope: String = "All") {
        filteredPapers = papers.filter { paper in
            let categoryMatch = (scope == "All") || (paper.exam == scope)
            return  categoryMatch && paper.name.lowercaseString.containsString(searchText.lowercaseString)
        }

        table.reloadData()
    }

    func updateSearchResultsForSearchController(searchController: UISearchController) {
        let searchBar = searchController.searchBar
        let scope = searchBar.scopeButtonTitles![searchBar.selectedScopeButtonIndex]
        filterContentForSearchText(searchController.searchBar.text!, scope: scope)

    }

    func searchBar(searchBar: UISearchBar, selectedScopeButtonIndexDidChange selectedScope: Int) {
        filterContentForSearchText(searchBar.text!, scope: searchBar.scopeButtonTitles![selectedScope])
    }

    // MARK: Defaults

    override func viewDidLoad() {
        super.viewDidLoad()

        self.getPapersData()

        searchController.searchResultsUpdater = self
        searchController.dimsBackgroundDuringPresentation = false
        definesPresentationContext = true
        table.tableHeaderView = searchController.searchBar
        searchController.searchBar.scopeButtonTitles = ["All", "ST1", "ST2", "PUT", "UT"]
        searchController.searchBar.delegate = self
        activityIndicator.startAnimating()


    }

    override func viewWillDisappear(animated: Bool) {
//        if searchController.active {
            self.searchController.resignFirstResponder()
//        }
    }




    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    // MARK: API call

    func getPapersData(){
        Alamofire.request(.GET, "http://silive.in/bytepad/rest/api/paper/getallpapers?query=")
            .responseJSON { response in

                self.activityIndicator.stopAnimating()
                self.activityIndicator.hidden = true

                // If the network works fine
                if response.result.isFailure != true {

                    self.loadingMessageLabel.hidden = true
                    self.table.hidden = false
                    //print(response.result)   // result of response serialization

                    let json = JSON(response.result.value!)

                    for item in json {
                        // Split the title on the . to remove the extention
                        let title = item.1["Title"].string!.characters.split(".").map(String.init)[0]
                        let category = item.1["ExamCategory"].string
                        let url = item.1["URL"].string
                        let detail = item.1["PaperCategory"].string

                        let paper = Paper(name: title, exam: category!, url: url!, detail: detail!)
                        self.papers.append(paper)

                    }
                    self.table.reloadData()

                }
                    // If the network fails
                else {
                    self.retryButton.hidden = false
                    self.loadingMessageLabel.text = "Check your internet connectivity"
                }

        }
    }


}

Answer 1

我在iOS12中遇到了這個問題，並通過將hostingPresentationContext設置為true來修復它，以便托管搜索控制器的viewcontroller。

self.definesPresentationContext = true

Answer 2

這是因為選項卡可能沒有單獨的導航控制器，可以為您提供黑屏。 為了單獨維護導航層次結構，您應該將uinavigationcontroller嵌入到uiviewcontroller中，並從IB檢查Top Bar作為不透明導航欄而不是Inferred 。 希望這可以幫助。 Cheerio

Answer 3

在幕后，正在呈現搜索控制器。 這是返回時導致黑屏的原因。

解決方案1

最簡單的方法是覆蓋UISearchController並在其viewDidDisappear設置isActive=false （ https://stackoverflow.com/a/39212080/215748 ）。 它有效，但我發現這個解決方案存在一些可用性問題。 我沒有追求它，所以它們可能很容易克服。

解決方案2

在遠離視圖控制器之前調用以下內容：

searchController.dismiss(animated: false, completion: nil)

將其添加到viewDidDisappear 。

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

func dismissSearch() {
    searchController.dismiss(animated: false, completion: nil)
}

不幸的是，切換標簽時不會viewDidDisappear ，因為正在顯示搜索控制器。 它收到了viewDidDisappear 。 要解決這個問題，您可以UITabBarController並實現UITabBarControllerDelegate 。

// don't forget to set the delegate
extension TabBarController: UITabBarControllerDelegate {
    func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {

        if let navigationController = viewControllers?[selectedIndex] as? UINavigationController {
            for myController in navigationController.viewControllers.flatMap({ $0 as? MyTableViewController }) {
                myController.dismissSearch()
            }
        }

        return true
    }

Answer 4

看起來您的UISearchController附加到的視圖將從視圖層次結構中刪除。 您可以將UISearchController視為在開始搜索時以模態方式呈現，並且definesPresentationContext屬性指示哪個UIViewController將是呈現它的人（ 更多內容 ）。

您可以在可能重復的問題的答案中獲得更多詳細信息： https ： //stackoverflow.com/a/37357242/300131

Answer 5

只需將UiNavigationcontroller添加到下載選項卡的uiviewcontroller，它將解決問題停電和隱藏的導航欄

Answer 6

如果你移動這段代碼怎么辦？

self.activityIndicator.stopAnimating()
self.activityIndicator.hidden = true

在你的結果之后？ 像這樣：

          // If the network works fine
          if response.result.isFailure != true {

               self.activityIndicator.stopAnimating()
               self.activityIndicator.hidden = true

（如果有效，你也需要將它包含在你的另一邊......）

 // If the network fails
                else {
                    self.activityIndicator.stopAnimating()
                    self.activityIndicator.hidden = true

                    self.retryButton.hidden = false
                    self.loadingMessageLabel.text = "Check your internet connectivity"
                }