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我的情況由UITable組成，當選中一行時，它將打開一個新的VC併發送一對變量。在DidSelectAtRow函數之前執行的Segue正在執行
我的問題是segue在運行函數DidSelectAtRow之前得到執行。
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
print ("hello")
self.selectedCellTitle = self.communities[indexPath.row]
self.cellId = indexPath.row
print ("now here: ", communityIds[cellId!])
self.performSegue(withIdentifier: "showCommunitySegue", sender: self)
}
我知道這是因爲上面的print命令沒有被執行。該應用程序然後在下一個屏幕時崩潰，因爲它預期存在的變量(cellId)爲空。
如果我刪除storyboard中的segue並運行，那麼該函數中的所有調試輸出都可以正常運行。只要我再次創建segue，應用程序就會切換到新的屏幕並在上述任何代碼運行之前崩潰。
要創建我賽格瑞我：
1）在我的內故事板VC1的UITableView細胞右鍵單擊並拖動到我的VC2
2）選擇類型爲show
3）複製VC 1中的prepare for segue函數的segue標識符名稱，並將其粘貼到Storyboard中屬於新segue的identifier屬性中。
任何想法？
下面是VC1的全碼：
import UIKit
class CommunitiesViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
var selectedCellTitle: String?
var cellId: Int?
var communities = [String]() //{ didSet { communitiesTableView.reloadData()
// }
// }
var communityIds = [String]()
var flag = true
var userEmailText: String?
var tempComId: Int?
@IBOutlet weak var joinCommunityButton: UIButton!
@IBOutlet weak var createCommunityButton: UIButton!
@IBOutlet weak var communitiesTableView: UITableView!
override func viewDidLoad() {
self.communitiesTableView.delegate = self
self.communitiesTableView.dataSource = self
super.viewDidLoad()
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return self.communities.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath as IndexPath)
cell.textLabel?.text = self.communities[indexPath.row]
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
print ("hello")
self.selectedCellTitle = self.communities[indexPath.row]
self.cellId = indexPath.row
print ("now here: ", communityIds[cellId!])
self.performSegue(withIdentifier: "showCommunitySegue", sender: self)
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(true)
if flag == true
{
self.communitiesTableView.reloadData()
let myUrl = URL(string: "http://www.quasisquest.uk/KeepScore/getDetails.php?");
var request = URLRequest(url:myUrl!);
request.httpMethod = "POST";
let postString = "email=\(self.userEmailText!)";
request.httpBody = postString.data(using: String.Encoding.utf8);
let task = URLSession.shared.dataTask(with: request) { (data: Data?, response: URLResponse?, error: Error?) in
DispatchQueue.main.async
{
if error != nil {
print("error=\(error)")
return
}
do{
let json = try JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? [String:AnyObject]
if let arr = json?["communities"] as? [[String:String]] {
self.communities = arr.flatMap { $0["name"]!}
self.communitiesTableView.reloadData()
}
} catch{
print(error)
}
}
}
task.resume()
}
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?)
{
if segue.identifier == "createCommunitySegue" {
let createCommunityController: CreateNewCommunity = segue.destination as! CreateNewCommunity
createCommunityController.myEmail = self.userEmailText
}
if segue.identifier == "joinCommunitySegue" {
let joinCommunityController: JoinCommunity = segue.destination as! JoinCommunity
joinCommunityController.myEmail = self.userEmailText
}
if segue.identifier == "showCommunitySegue" {
let showCommunityController: ShowCommunityViewController = segue.destination as!ShowCommunityViewController
print("yes here: ", self.cellId!)
showCommunityController.communityIsCalled = self.selectedCellTitle
showCommunityController.comIds = self.communityIds
showCommunityController.communityId = self.cellId
}
}
}
你應該從viewcontroller頂部創建segue而不是從單元格 – Vinodh
從ViewController創建segue到ViewController – Rajat
請使用以下帖子瞭解如何以編程方式繼續並使用它http： //stackoverflow.com/a/21205550/1142743 – Vinodh