完成 ViewController 中的所有任务，然后跳转到 Xcode8 中的另一个 Swift 3
Complete all the task in a ViewController before jumping to another in Xcode8 Swift 3
所以，我仍在处理我的 poem 移动项目。我正在处理这个登录模块。这里发生的是它从一个 ViewController 跳到另一个 ViewController.. 也许是因为任务？有什么方法可以完成第一个ViewController中的所有任务，然后跳转到第二个ViewController（时间线ViewController）？如果第一个 ViewController 中的任务尚未完成，想阻止它进入时间线ViewController？
我希望有人能帮我解决这个问题.. :( 提前谢谢你！
这是我的ViewController代码
import UIKit
class ViewController: UIViewController {
@IBOutlet weak var txtusername: UITextField!
@IBOutlet weak var txtpassword: UITextField!
@IBOutlet weak var lblResult: UILabel!
var returnVal:String? = nil
@IBOutlet weak var btnLogin: UIButton!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
@IBAction func btnLogin_Tapped(sender: UIButton) {
let url:NSURL = NSURL(string: "http://192.168.1.6/Test/login.php")!
let request:NSMutableURLRequest = NSMutableURLRequest(url:url as URL)
let bodyData = "username=\(txtusername.text!)&password=\(txtpassword.text!)"
request.httpMethod = "GET"
request.httpBody = bodyData.data(using: String.Encoding.utf8);
// NSURLConnection.sendAsynchronousRequest(request as URLRequest, queue: OperationQueue.main){(response, data, error) in
//print(response)
// }
let task = URLSession.shared.dataTask(with: request as URLRequest)
{
data, response, error in
guard let data = data, error == nil else {
print ("Error = \(error?.localizedDescription ?? "Unknown error")")
return
}
if let response = response {
print ("Response = \(response)")
}
if let responseString = String(data: data, encoding: .utf8) {
print ("Response data = \(responseString)")
}
//Converting response to NSDictionary
guard let json = try? JSONSerialization.jsonObject(with: data, options: .allowFragments),
let responseObject = json as? String,
let returnValidation = responseObject as? String else {
print("did not validate")
return
}
DispatchQueue.main.async()
{
self.returnVal = returnValidation
print("RETURN VALUE: \(self.returnVal!)")
self.performSegue(withIdentifier: "signinSegue", sender: self)
}
}
task.resume()
}
func AlertMessage(titleA: String, messageA: String)
{
let alert = UIAlertController(title: titleA, message: messageA, preferredStyle: UIAlertControllerStyle.alert)
let alertAction = UIAlertAction(title: "Ok", style:UIAlertActionStyle.default){(UIAlertAction)-> Void in }
alert.addAction(alertAction)
present(alert, animated: true){() -> Void in}
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if(segue.identifier == "signinSegue")
{
if(self.returnVal != nil)
{
if(self.returnVal! == "true")
{
let viewController = segue.destination as! TimelineViewController
viewController.passedValue = self.returnVal!
viewController.viewDidLoad()
}
else if (self.returnVal! == "false")
{
print("Incorrect Password!")
}
}
else
{
print("Empty")
}
}
}
}
这是我的时间轴ViewController代码
import UIKit
import Foundation
struct Poem {
let poemTitle: String
let poemBody: String
init?(dictionary: [String: Any]) {
guard let poemTitle = dictionary["Title"] as? String,
let poemBody = dictionary["Body"] as? String else {
print("Did not find fullName/Bio")
return nil
}
self.poemTitle = poemTitle
self.poemBody = poemBody
}
}
class TimelineViewController: UIViewController {
@IBOutlet weak var contentTableView: UITableView!
@IBOutlet weak var poemBodyText: UITextView!
@IBOutlet weak var poemTitleText: UILabel!
var poems = [Poem]()
var passedValue:String? = nil
@IBOutlet weak var oPostBtn: UIButton!
override func viewDidLoad() {
super.viewDidLoad()
if(passedValue != nil)
{
getPoems()
}
else {
print("Empty")
}
}
func getPoems()
{
let url = URL(string: "http://192.168.1.6/Test/feed1.php")!
var request = URLRequest(url: url)
request.httpMethod = "GET"
let task = URLSession.shared.dataTask(with: request as URLRequest)
{
data, response, error in
guard let data = data, error == nil else {
print("Error = \(error?.localizedDescription ?? "Unknown error")")
return
}
if let response = response {
print("Response = \(response)")
}
if let responseString = String(data: data, encoding: .utf8){
print ("Response data = \(responseString)")
}
//Converting response to NSDictionary
guard let json = try? JSONSerialization.jsonObject(with: data),
let responseObject = json as? [String:Any],
let returnPoems = responseObject["returnPoems"] as? [[String:Any]] else {
print ("Did not find return Poems")
return
}
print (returnPoems)
DispatchQueue.main.async {
self.poems = returnPoems.flatMap { Poem(dictionary: [=14=]) }
self.contentTableView.reloadData() }
}
task.resume()
}
/* override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}*/
func AlertMessage(titleA: String, messageA: String)
{
let alert = UIAlertController(title: titleA, message: messageA, preferredStyle: UIAlertControllerStyle.alert)
let alertAction = UIAlertAction(title: "Ok", style: UIAlertActionStyle.default){(UIAlertAction)-> Void in }
alert.addAction(alertAction)
present(alert, animated: true){() -> Void in}
}
@IBAction func aPostBtn(_ sender: Any) {
var count = 0
while(count < 2)
{
//print("RESPONSE!!! : \(poemTitle[count])")
count = count + 1;
}
}
}
extension TimelineViewController: UITableViewDelegate, UITableViewDataSource {
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
guard let cell = contentTableView.dequeueReusableCell(withIdentifier: "PoemTableViewCell", for: indexPath) as? PoemTableViewCell else
{
fatalError("The dequeued cell is not an instance of PoemTableViewCell")
}
let poem = poems[indexPath.row]
cell.poemTitleText?.text = poem.poemTitle
cell.poemBodyText?.text = poem.poemBody
// cell.textLabel?.text = poem.poemTitle
// cell.detailTextLabel?.text = poem.poemBody
return cell
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return poems.count
}
func tableView(_ tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
print("You selected cell #\(indexPath.row)!")
let poem = poems[indexPath.row]
print(poem)
}
}
在 btnLogin_Tapped 中删除 DispatchQueue.main.async()。我不明白你为什么需要这个。它创建一个新队列并异步执行其中的代码。
也删除 viewController.viewDidLoad()。你不应该自己调用 viewDidLoad，它会在新视图控制器出现时自动调用。
另一件可能导致问题的事情是，如果您在 Storyboard 中创建了一个从登录按钮到 TimelineViewController 的 segue（Ctrl + 拖动）。您应该在 btnLogin_Tapped 末尾执行 segue 时将其删除。
所以，我仍在处理我的 poem 移动项目。我正在处理这个登录模块。这里发生的是它从一个 ViewController 跳到另一个 ViewController.. 也许是因为任务？有什么方法可以完成第一个ViewController中的所有任务，然后跳转到第二个ViewController（时间线ViewController）？如果第一个 ViewController 中的任务尚未完成，想阻止它进入时间线ViewController？
我希望有人能帮我解决这个问题.. :( 提前谢谢你！
这是我的ViewController代码
import UIKit
class ViewController: UIViewController {
@IBOutlet weak var txtusername: UITextField!
@IBOutlet weak var txtpassword: UITextField!
@IBOutlet weak var lblResult: UILabel!
var returnVal:String? = nil
@IBOutlet weak var btnLogin: UIButton!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
@IBAction func btnLogin_Tapped(sender: UIButton) {
let url:NSURL = NSURL(string: "http://192.168.1.6/Test/login.php")!
let request:NSMutableURLRequest = NSMutableURLRequest(url:url as URL)
let bodyData = "username=\(txtusername.text!)&password=\(txtpassword.text!)"
request.httpMethod = "GET"
request.httpBody = bodyData.data(using: String.Encoding.utf8);
// NSURLConnection.sendAsynchronousRequest(request as URLRequest, queue: OperationQueue.main){(response, data, error) in
//print(response)
// }
let task = URLSession.shared.dataTask(with: request as URLRequest)
{
data, response, error in
guard let data = data, error == nil else {
print ("Error = \(error?.localizedDescription ?? "Unknown error")")
return
}
if let response = response {
print ("Response = \(response)")
}
if let responseString = String(data: data, encoding: .utf8) {
print ("Response data = \(responseString)")
}
//Converting response to NSDictionary
guard let json = try? JSONSerialization.jsonObject(with: data, options: .allowFragments),
let responseObject = json as? String,
let returnValidation = responseObject as? String else {
print("did not validate")
return
}
DispatchQueue.main.async()
{
self.returnVal = returnValidation
print("RETURN VALUE: \(self.returnVal!)")
self.performSegue(withIdentifier: "signinSegue", sender: self)
}
}
task.resume()
}
func AlertMessage(titleA: String, messageA: String)
{
let alert = UIAlertController(title: titleA, message: messageA, preferredStyle: UIAlertControllerStyle.alert)
let alertAction = UIAlertAction(title: "Ok", style:UIAlertActionStyle.default){(UIAlertAction)-> Void in }
alert.addAction(alertAction)
present(alert, animated: true){() -> Void in}
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if(segue.identifier == "signinSegue")
{
if(self.returnVal != nil)
{
if(self.returnVal! == "true")
{
let viewController = segue.destination as! TimelineViewController
viewController.passedValue = self.returnVal!
viewController.viewDidLoad()
}
else if (self.returnVal! == "false")
{
print("Incorrect Password!")
}
}
else
{
print("Empty")
}
}
}
}
这是我的时间轴ViewController代码
import UIKit
import Foundation
struct Poem {
let poemTitle: String
let poemBody: String
init?(dictionary: [String: Any]) {
guard let poemTitle = dictionary["Title"] as? String,
let poemBody = dictionary["Body"] as? String else {
print("Did not find fullName/Bio")
return nil
}
self.poemTitle = poemTitle
self.poemBody = poemBody
}
}
class TimelineViewController: UIViewController {
@IBOutlet weak var contentTableView: UITableView!
@IBOutlet weak var poemBodyText: UITextView!
@IBOutlet weak var poemTitleText: UILabel!
var poems = [Poem]()
var passedValue:String? = nil
@IBOutlet weak var oPostBtn: UIButton!
override func viewDidLoad() {
super.viewDidLoad()
if(passedValue != nil)
{
getPoems()
}
else {
print("Empty")
}
}
func getPoems()
{
let url = URL(string: "http://192.168.1.6/Test/feed1.php")!
var request = URLRequest(url: url)
request.httpMethod = "GET"
let task = URLSession.shared.dataTask(with: request as URLRequest)
{
data, response, error in
guard let data = data, error == nil else {
print("Error = \(error?.localizedDescription ?? "Unknown error")")
return
}
if let response = response {
print("Response = \(response)")
}
if let responseString = String(data: data, encoding: .utf8){
print ("Response data = \(responseString)")
}
//Converting response to NSDictionary
guard let json = try? JSONSerialization.jsonObject(with: data),
let responseObject = json as? [String:Any],
let returnPoems = responseObject["returnPoems"] as? [[String:Any]] else {
print ("Did not find return Poems")
return
}
print (returnPoems)
DispatchQueue.main.async {
self.poems = returnPoems.flatMap { Poem(dictionary: [=14=]) }
self.contentTableView.reloadData() }
}
task.resume()
}
/* override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}*/
func AlertMessage(titleA: String, messageA: String)
{
let alert = UIAlertController(title: titleA, message: messageA, preferredStyle: UIAlertControllerStyle.alert)
let alertAction = UIAlertAction(title: "Ok", style: UIAlertActionStyle.default){(UIAlertAction)-> Void in }
alert.addAction(alertAction)
present(alert, animated: true){() -> Void in}
}
@IBAction func aPostBtn(_ sender: Any) {
var count = 0
while(count < 2)
{
//print("RESPONSE!!! : \(poemTitle[count])")
count = count + 1;
}
}
}
extension TimelineViewController: UITableViewDelegate, UITableViewDataSource {
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
guard let cell = contentTableView.dequeueReusableCell(withIdentifier: "PoemTableViewCell", for: indexPath) as? PoemTableViewCell else
{
fatalError("The dequeued cell is not an instance of PoemTableViewCell")
}
let poem = poems[indexPath.row]
cell.poemTitleText?.text = poem.poemTitle
cell.poemBodyText?.text = poem.poemBody
// cell.textLabel?.text = poem.poemTitle
// cell.detailTextLabel?.text = poem.poemBody
return cell
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return poems.count
}
func tableView(_ tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
print("You selected cell #\(indexPath.row)!")
let poem = poems[indexPath.row]
print(poem)
}
}
在 btnLogin_Tapped 中删除 DispatchQueue.main.async()。我不明白你为什么需要这个。它创建一个新队列并异步执行其中的代码。
也删除 viewController.viewDidLoad()。你不应该自己调用 viewDidLoad，它会在新视图控制器出现时自动调用。
另一件可能导致问题的事情是，如果您在 Storyboard 中创建了一个从登录按钮到 TimelineViewController 的 segue（Ctrl + 拖动）。您应该在 btnLogin_Tapped 末尾执行 segue 时将其删除。