我找不到我没有打开标签的地方，所以我可以执行我的segue。它一直说标签没有。文本和致命错误：在展开可选值时意外发现nil
我只是想让视图控制器的标题等于标签文本teamNameLabel
import UIKit
class TimelineTableViewController: UITableViewController {
var timelineData:NSMutableArray! = NSMutableArray()
override init(style: UITableViewStyle) {
super.init(style: style)
// Custom initialization
}
required init(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
@IBAction func loadData(){
timelineData.removeAllObjects()
var findTimelineData:PFQuery = PFQuery(className: "Sweets")
findTimelineData.findObjectsInBackgroundWithBlock{
(objects:[AnyObject]!, error:NSError!)->Void in
if error == nil{
for object in objects{
let sweet:PFObject = object as PFObject
self.timelineData.addObject(sweet)
}
let array:NSArray = self.timelineData.reverseObjectEnumerator().allObjects
self.timelineData = NSMutableArray(array: array)
self.tableView.reloadData()
}
}
}
override func viewDidAppear(animated: Bool) {
self.loadData()
if PFUser.currentUser() == nil{
var loginAlert:UIAlertController = UIAlertController(title: "Sign Up / Login", message: "Please sign up or login", preferredStyle: UIAlertControllerStyle.Alert)
loginAlert.addTextFieldWithConfigurationHandler({
textfield in
textfield.placeholder = "Your username"
})
loginAlert.addTextFieldWithConfigurationHandler({
textfield in
textfield.placeholder = "Your password"
textfield.secureTextEntry = true
})
loginAlert.addAction(UIAlertAction(title: "Login", style: UIAlertActionStyle.Default, handler: {
alertAction in
let textFields:NSArray = loginAlert.textFields! as NSArray
let usernameTextfield:UITextField = textFields.objectAtIndex(0) as UITextField
let passwordTextfield:UITextField = textFields.objectAtIndex(1) as UITextField
PFUser.logInWithUsernameInBackground(usernameTextfield.text, password: passwordTextfield.text){
(user:PFUser!, error:NSError!)->Void in
if user != nil{
println("Login successfull")
}else{
println("Login failed")
}
}
}))
loginAlert.addAction(UIAlertAction(title: "Sign Up", style: UIAlertActionStyle.Default, handler: {
alertAction in
let textFields:NSArray = loginAlert.textFields! as NSArray
let usernameTextfield:UITextField = textFields.objectAtIndex(0) as UITextField
let passwordTextfield:UITextField = textFields.objectAtIndex(1) as UITextField
var sweeter:PFUser = PFUser()
sweeter.username = usernameTextfield.text
sweeter.password = passwordTextfield.text
sweeter.signUpInBackgroundWithBlock{
(success:Bool!, error:NSError!)->Void in
if error == nil{
println("Sign Up successfull")
}else{
let errorString = error.localizedDescription
println(errorString)
}
}
}))
self.presentViewController(loginAlert, animated: true, completion: nil)
}
}
override func viewDidLoad() {
super.viewDidLoad()
// Uncomment the following line to preserve selection between presentations
// self.clearsSelectionOnViewWillAppear = false
// Uncomment the following line to display an Edit button in the navigation bar for this view controller.
// self.navigationItem.rightBarButtonItem = self.editButtonItem
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// #pragma mark - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView?) -> Int {
// #warning Potentially incomplete method implementation.
// Return the number of sections.
return 1
}
override func tableView(tableView: UITableView?, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete method implementation.
// Return the number of rows in the section.
return timelineData.count
}
override func tableView(tableView: UITableView?, cellForRowAtIndexPath indexPath: NSIndexPath?) -> UITableViewCell {
let cell:SweetTableViewCell = tableView!.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath!) as SweetTableViewCell
let sweet:PFObject = self.timelineData.objectAtIndex(indexPath!.row) as PFObject
cell.sweetTextView.alpha = 0
cell.timestampLabel.alpha = 0
cell.usernameLabel.alpha = 0
cell.teamNameLabel.alpha = 0
cell.sweetTextView.text = sweet.objectForKey("content") as String
cell.teamNameLabel.text! = sweet.objectForKey("teamName") as String
var dataFormatter:NSDateFormatter = NSDateFormatter()
dataFormatter.dateFormat = "yyyy-MM-dd HH:mm"
cell.timestampLabel.text = dataFormatter.stringFromDate(sweet.createdAt)
var findSweeter:PFQuery = PFUser.query()
findSweeter.whereKey("objectId", equalTo: sweet.objectForKey("sweeter").objectId)
findSweeter.findObjectsInBackgroundWithBlock{
(objects:[AnyObject]!, error:NSError!)->Void in
if error == nil{
let user:PFUser = (objects as NSArray).lastObject as PFUser
cell.usernameLabel.text = user.username
UIView.animateWithDuration(0.5, animations: {
cell.sweetTextView.alpha = 1
cell.timestampLabel.alpha = 1
cell.usernameLabel.alpha = 1
cell.teamNameLabel.alpha = 1
})
}
}
return cell
}
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
if segue.identifier == "viewTeam" {
if let indexPath = self.tableView.indexPathForSelectedRow() {
let vc = segue.destinationViewController as TeamViewController
vc.title = timelineData[indexPath.row].teamNameLabel.text
}
/*
if let indexPath = self.tableView.indexPathForSelectedRow() {
let controller = (segue.destinationViewController as UINavigationController).topViewController as TeamViewController
controller.title = timelineData[indexPath.row].teamNameLabel
*/
//viewController.title = TimelineData.teamNameLabel.text
//}
}
}
我的问题出在我准备的短信里
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
if segue.identifier == "viewTeam" {
if let indexPath = self.tableView.indexPathForSelectedRow() {
let vc = segue.destinationViewController as TeamViewController
vc.title = timelineData[indexPath.row].teamNameLabel.text
}
/*
if let indexPath = self.tableView.indexPathForSelectedRow() {
let controller = (segue.destinationViewController as UINavigationController).topViewController as TeamViewController
controller.title = timelineData[indexPath.row].teamNameLabel
*/
//viewController.title = TimelineData.teamNameLabel.text
//}
}
}
这是我的手机课
import UIKit
class SweetTableViewCell: UITableViewCell {
@IBOutlet var usernameLabel: UILabel! = UILabel()
@IBOutlet var timestampLabel: UILabel! = UILabel()
@IBOutlet var teamNameLabel: UILabel! = UILabel()
@IBOutlet var sweetTextView: UITextView! = UITextView()
override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
// Initialization code
}
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
//teamNameLabel.text = ""
}
required init(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
override func setSelected(selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
// Configure the view for the selected state
}
}
这让我发疯了
最佳答案
我认为问题在于，在prepareForSegue方法中，您在视图控制器的错误实例上设置了标题。
创建变量vc，并在其上设置标题，但这不会更改destinationViewController实例。
请尝试以下代码：
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
if segue.identifier == "viewTeam" {
if let indexPath = self.tableView.indexPathForSelectedRow() {
(segue.destinationViewController as TeamViewController).title = timelineData[indexPath.row].teamNameLabel.text
}
/*
if let indexPath = self.tableView.indexPathForSelectedRow() {
let controller = (segue.destinationViewController as UINavigationController).topViewController as TeamViewController
controller.title = timelineData[indexPath.row].teamNameLabel
*/
//viewController.title = TimelineData.teamNameLabel.text
//}
}
}
关于parsing - 从表 View 中选择到 View Controller ，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/26346364/