I'm having trouble updating the UITextField for an iPhone app. I've set the layout with the Interface Builder, created an instance of the text field in the ViewController, and set the ViewController as the delegate for the text field.
The text field object in code doesn't seem to be responding when I enter in information and press Done.
Does anyone have any ideas why its not working?
If you are creating the text field in interface builder, you don't need to also alloc and init it in code. Link the text field to files owner in IB (I'm assuming files owner is your view controller) as the delegate. If you need to refer to it specifically, also create and outlet in your view controller and link that to your text field. This is covered in the most basic tutorial apps in the docs.
To respond when the done button is pressed, implement the textFieldShouldReturn method from the UITextFieldDelegate protocol. Resign first responder in that method and return YES.
Is your text field connected to the IBOutlet in your code? Maybe if you post some related code it would be helpful.
Related
I am using Xcode 9.1 and trying to build a program. I have designed one textbook , one label and one button. Now I am trying to place the textbook in view controller to code it, But Unable to do this.
In your view controller, you want to setup an outlet. Add a property like
#IBOutlet var textField: UITextField?
In the interface you have screenshot, a small circle should then appear next to it, which you want to drag over to connect to your text field. This creates a binding between the property in your controller and the view element.
You can then reference this property in your controller to access the text field.
I am working with keyboard resign features in iPhone app development. I would like to know why
self.textField.delegate = self
needs to be included into the viewDidLoad of a viewController. I have tried to find reasons of this but no explanation has been clear so far.
A few points
The reason you need to set the delegate is because without it the view doesn't know about the view controller. So it wouldn't know about your method textFieldDidEndEditing and it would never be called.
That is the basic premise of delegate, you are telling that object, "here is an object that I want you to call methods on"
It doesn't have to be set in viewDidLoad - but it's often the most convient place to set up delegates for views.
The delegate doesn't have to be the view controller (self), in your case it's the simplest way, but with a UITableView its common to have another class be the delegate so that all the logic isn't in one place and so it can be changed.
The UITextFieldDelegate protocol defines methods that you use to manage the editing and validation of text in a UITextField object. All of the methods of this protocol are optional.
A text field calls the methods of its delegate in response to important changes. You use these methods to validate text that was typed by the user, to respond to specific interactions with the keyboard, and to control the overall editing process. Editing begins shortly before the text field becomes the first responder and displays the keyboard (or its assigned input view).
From more info. check apple doc.
Its not necessary to use self.textField.delegate = self if you don't want to manage the editing and validation of text in a UITextField object as all the methods of UITextFieldDelegate is optional.
For your other questions like what does .delegate = self do??
When you "set the delegate," what you are doing is saying where you want the messages to go.
Hence,
blah.delegate = amazingPlace will send the messages to "amazingPlace".
blah.delegate = somewhereElse will send the messages to "somewhereElse".
blah.delegate = self will send the messages to you.
... check this source link for details
Delegates are key concepts in iOS development so I'd suggest taking a good look at the documentation for them. It can be particularly useful to create your own custom delegates in certain situations too so understanding and using them in the right places can really help improve the structure of your projects.
There are a couple of key reasons for using them. Firstly, they allow safe communication between classes. In your example, the textField object that you're using is communicating back to your view controller. This is why you need to set your view controller as its delegate. Otherwise the text field doesn't have a delegate object (your view controller) to communicate with. The text field fires certain methods at certain times, such as textFieldDidBeginEditing, and calls these on its delegate object if it has one. When you register your view controller as the text view's delegate you can tap into these callbacks.
The other benefit is that delegates allow you to separate concerns and encapsulate or abstract responsibilities. It might be that the main concern for the text view is how to handle text in its view but not necessarily what to do when has been entered, or when the return button in the keyboard is pressed, or how to validate text that has been input. It's better that these tasks are handed over to something else, such as a delegate (in Obj-C parlance), and that is why in your example you have to register one class as the delegate for another.
As stated before, UITextfield delegation allows you to control events on your textfield.
You ll have the ability to edit functions like
textFieldShoulEndEditing
or
textFieldDidEndEditing
in order to add custom rules, for example : text validation.
Take a look at Apple doc.
If you don't need it, you can delete this line and UITextfieldDelegate on your class declaration.
You need to either set the delegate of a UITextField in code with self.textField.delegate = self
or make your viewcontroller (or any other class) a delegate with class MyViewController: UITextFieldDelegate and set the delegate of the UITextField in the storyboard by control dragging from the textfield to the viewController.
Where should I customise my IBOutlets?
Say I have created a button with interface builder, created an IBOutlet for it and I would want to change a property during runtime (ex: background color or localized title).
I would think of adding it to the viewDidLoad method, but outlets aren't yet created.
I remember having nil outlets in viewDidLoad, but I might be wrong.
If I move it viewWillAppear, the code will be executed every time the view controller's view appears.
Is there any better place for my IBOutlet related code, so it's only executed once?
Obviously I can do just about any customization using only the interface builder and making use of the User defined runtime attributes or localized stroryboards, but I don't like that since it's much more tedious to change later.
From the Doc
Its clearly says about the Views loaded into the memory in the -viewDidLoad() delegate itself.
I would think of adding it to the viewDidLoad method, but outlets
aren't yet created.
It is a false statement, Because you only get the viewDidLoad: message after IBOutlets are created. So you can safely do any customization in viewDidLoad:
Let’s say you have a Button you want to customise. You put the button at the place where you want it to be and then open the “Identity Inspector” on the right.
There is a textfield for “Custom Class”:
I usually create a subclass of UIButton / NSButton (depending on iOS or OSX) and edit the behaviour, drawing methods and functionality in this class file. Then just add the name of this class in this textfield. Voila!
I've got a view controller xib file with several views in it. I'm building a wizard-type interface. I'm just doing a simple fade between the views, and I'm already using a navigation controller for the main interface. I'd prefer not to use one for this wizard. Anyway, in the views, each panel has at least a button, some sort of input field (usually a UITextField) and some helper text hard coded in a UILabel.
The problem is that not all the UITextField objects are calling the textFieldDidChange method in the delegate (File's Owner - .m file associated with the xib), but all the UITextField objects ARE calling the textFieldDidBeginEditing method.
Makes no sense to me. I feel like I must be missing something simple in how I set up the screens, but I'll be darned if I can figure it out. Each of the screens all look identical in the property sheets (on the right hand side of Xcode), and everything is wired up correctly in the File's Owner property sheet, both in IBOutlet and IBActions.
Here are some shots of what's going on...
Ideas? Thanks.
Here are links to the screen caps of the vital parts.
(being a new member is making it hard to add all the info I need with screen caps!)
As far as I now, there is no delegate method with the header textFieldDidChange. You have created a method of your own, which is depending on a NSNotification. Make sure all the UITextFields are send the right notification.
There is no such method on a UITextFieldDelegate
You may have confused textViewDidChange, which is a delegate method for a UITextView, but itis passed the UITextView that generated the event, not an NSNotification.
Seems like you want textField:shouldChangeCharactersInRange:replacementString: instead.
This is resolved. I'm a knucklehead. :-)
I was attaching my own notifier/observer and hadn't done so for the last few UITextField objects. Sorry to bother y'all.
I'm trying to show a search bar above a table with a list of recent searches that will swap to matching search results once someone enters a search term.
I want to set a custom class MySearchViewController to be the delegate for doing the search and managing the display of search results back to the table so that I can separate the code and not have conditional statements in the default controller.
I've found a bunch of examples that describe how to do this in code but I can't figure out how to do it using Interface Builder.
I've tried dragging a new viewcontroller into my xib and setting the custom class to MySearchViewController and then dragging outlets from the SearchDisplayController as hinted at here: http://goo.gl/RgmwG
I've also tried dragging an Object into the objects column and changing this class to MySearchViewController.
But I feeling completely lost and really just trying things randomly. I'm guessing that I also need to create a property/IBOutlet for the SearchDisplayController somewhere but again lost.
If anyone has a reference to how to go about this I'd be so happy!
Like most problems, it seems pretty obvious in retrospect.
Add an 'object' placeholder in interface builder (orange cube).
Change the objects custom class to the class you want to be the delegate - e.g. MySearchViewController
Remove the default outlets from the standard SearchDisplayContoller to connect with the MySearchViewController object (see screenshot)
Make sure that the new delegate has an outlet to a parent view (in my case View)
Make sure that the delegate class is initiated from somewhere
// I did this from the parent ViewConroller, but probably better from the main app delegate?
#property (strong, nonatomic) IBOutlet MSSearchViewController *searchViewController;
Hope this helps someone else who was also stuck!