UIStoryboard Container Attach IBOutlet To Parent ViewController

问题

I wanted to use a UITableView which contained static cells with a UITextField inside attached to my LoginViewController. I have added IBOutlets in the header file that correspond to the UITextFields in the storyboard. Unfortunately Xcode does not allow static content inside a UITableView you need to use a UITableViewController.

Therefore I split out the UITableView from the storyboard and used a ContainerView to embed a UITableViewController which works well. Attached a screenshot of the setup.

The problem I am now facing is I cannot link the UITextFields to my LoginViewController, you can see from my screenshot that I have added an Object to the UITableViewController which I have set to my LoginViewController and managed to link the UITextFields to it. But when the main view loads it says my UITextFields are nil

How can I link my UITextFields to my IBOutlets in my LoginViewController?

Edit: If I have to subclass the UITableViewController it seems like I should have just used a prototype cell... Any other suggestions?

回答1:

1.) Name your embed segue to "TextFields"

2.) If you haven't already, subclass UITableViewController and set your table view controller to this class in the storyboard. Let's call it TextFieldsTableViewController.

3.) Again, if you haven't already, add IBOutlets for your text fields into TextFieldsTableViewController's public interface:

@property (weak, nonatomic) IBOutlet UITextField *firstNameField;
@property (weak, nonatomic) IBOutlet UITextField *usernameField;
@property (weak, nonatomic) IBOutlet UITextField *emailField;
@property (weak, nonatomic) IBOutlet UITextField *passwordField;

4.) Add properties for your text fields into your LoginViewController's public interface (note that unlike the above, these are not weak (they are also not IBOutlets, but that doesn't really matter)):

@property (nonatomic) UITextField *firstNameField;
@property (nonatomic) UITextField *usernameField;
@property (nonatomic) UITextField *emailField;
@property (nonatomic) UITextField *passwordField;

5.) In LoginViewController's prepareForSegue:sender: method, map the TextFieldsTableViewController's text fields to self's text fields after forcing the table view controller's view to load immediately:

if ([segue.identifier isEqualToString:@"TextFields"]) {

    TextFieldsTableViewController *textFieldsVC = segue.destinationViewController;

    // IMPORTANT: This forces the view to load and the outlets to get set.
    // If you don't do this, textFieldsVC's IBOutlets will all be nil at this point.
    // This is slightly inelegant in my opinion, but it works. A better solution might
    // be to set the text fields in TextFieldsTableViewController's viewDidLoad method.
    [textFieldsVC view];

    self.firstNameField = textFieldsVC.firstNameField;
    self.usernameField = textFieldsVC.usernameField;
    self.emailField = textFieldsVC.emailField;
    self.passwordField = textFieldsVC.passwordField;
}

6.) You should now be able to access the text fields in LoginViewController's viewDidLoad method.

回答2:

Since progressing in the project, I have learnt that it would have been better to not use a static UITableView seeing as you can get into complications like this quickly.

If you were really against doing any subclassing you can add this to the viewDidAppear: method - (Because the UITableView didn't load any cells at viewWillAppear:

[self.childViewControllers enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
    UIViewController *childViewController = obj;
    //Make sure we are using the correct view controller -
    if([childViewController.restorationIdentifier isEqualToString:@"LoginTableViewController"]){
        self.username = (UITextField *)[childViewController.view viewWithTag:-2];
        self.email = (UITextField *)[childViewController.view viewWithTag:-3];
        self.password = (UITextField *)[childViewController.view viewWithTag:-4];
    }
}];

Just make sure to tag your views in the Storyboard.

来源：https://stackoverflow.com/questions/23890808/uistoryboard-container-attach-iboutlet-to-parent-viewcontroller

标签

ios

xcode

storyboard

iboutlet