does anyone know, which method is called when I set the default title of a UIButton in interface builder?
I have subclassed UIButton and want to provide setting its title easily via interface builder. I assume that it works similar to the User Defined Runtime Attributes which call the setValue: forKeyPath: method.
Edit: So I'm looking for that method which works like "the interface builder tells the button to have that certain title" when instantiating the view.
Thanks in advance!
Interface Builder doesn't call setTitle: method, instead you can override initWithCoder: and awakeFromNib in your UIButton's subclass
- (id) initWithCoder:(NSCoder *)aCoder{
if(self = [super initWithCoder:aCoder){
NSLog([self titleForState:UIControlStateNormal]);
}
return self;
}
The method you're looking for is setTitle:forState:.
Related
I want to write a category on UINavigationItem to make changes to barBackButtonItem across my entire app.
From what I have been told in the comments here ( Change BackBarButtonItem for All UIViewControllers? ), I should "override backBarButtonItem in it, then your method will be called whenever their back bar button item is called for." - but how do I know what method to override? I have looked at the UINavigationItem documentation, and there are multiple methods used for initializing a backBarButtonItem. How do I determine which method I should override in my category?
If you want to override backBarButtonItem, override backBarButtonItem. There is one and only one method called backBarButtonItem. ObjC methods are uniquely determined by their name.
You'd do it like so:
#implementation UINavigationItem (MyCategory)
- (UIBarButtonItem *)backBarButtonItem
{
return [[UIBarButtonItem alloc] initWithTitle:nil style:UIBarButtonItemStylePlain target:nil action:nil]
}
#end
I'm not saying it's a good idea, but that's how you'd do it.
You want a subclass of UIViewController instead of a catagory.
For example:
#interface CustomViewController : UIViewController
#end
#implementation CustomViewController
-(void) viewDidLoad {
[super viewDidLoad];
self.navigationItem.backBarButtonItem.title = #"";
}
#end
Now you just need to use the CustomViewController class for your view controllers, and they will all have the changes applied to them.
If you're doing this programatically, then you'll just want to change the superclass of the view controllers:
From this.... to this...
If you're using storyboards, you'll want to change the superclass from within the Identity Inspector...
In a storyboard when I add a new view (for example a TableView) I can select a class in the "Custom class" field in the identity inspector.
If I understand the rule of this class, I expect this class "answer" to messages sent to my tableview (i.e. this class is my table viewcontroller) and when I run my project it seems to do what I want.
My question is: To do this, I expected my Xcode automatically instantiates an object of my controller class and "link" this object to my GUI in storyboard.
However, I expected that if I override the init method of my controller class with
-(id) init
{
self=[super init];
NSLog(#"object controller created automatically");
return self;
}
I have the string in output when is created my controller object.
Instead, I have no output.
Why is this happenig and what is wrong with the code?
UIView set up by storyboard never called init.
Instead, you should use - (void)awakeFromNib in which your outlet has been ready to use.
- (void)awakeFromNib {
[super awakeFromNib];
NSLog(#"object controller created automatically");
}
From awakeFromNib documentation:
Objects that conform to the NSCoding protocol (including all subclasses of UIView and UIViewController) are initialized using their initWithCoder: method. All objects that do not conform to the NSCoding protocol are initialized using their init method.
If I understand you question you want a message to be printed whenever your viewController is initialised.
Why dont you write the code in the viewDidLoad?
Like:
In your YourControllerClass.m
-(void)viewDidLoad {
[super viewDidLoad];
NSLog(#"Controller created");
}
Now set the class of the controller in the storyboard to YourControllerClassand the message should be printed whenever your controller is created.
Cheers
P.s.: If you still need help or got a question, please write a comment.
So I'm trying to create a custom NSTableView by subclassing NSTableCellView and a NSTextField inside of the cellview. I'm trying to write some init code in the initWithFrame: method for the NSTextField subclass (TableTextField), but it looks like the initWithFrame: method isn't being called at all, even when I create new rows for the NSTableView, which each contain an instance of the TableTextField. Here's the code in the TableTextField.m file:
#import "TableTextField.h"
#implementation TableTextField
- (id)initWithFrame:(NSRect)frame//This isn't even being called.
{
self = [super initWithFrame:frame];
if (self) {
self.ad = [[NSApplication sharedApplication] delegate];
}
return self;
}
- (void)mouseDown:(NSEvent*) theEvent{
NSLog(#"A");//TEST
self.ad = [[NSApplication sharedApplication] delegate];//This works. Why isn't it happening in init?
[self.ad.classViewController addHomeworkItem];
}
#end
I've been able to solve the problem by just putting the code i need in the mouseDown: method, which is really the only thing I need, but I feel like it's bad practice to redeclare self.ad every time i need to use it, rather than just declaring it once and accessing it for each use, and I can't seem to figure out why initWithFrame: isn't being called. I'm assuming it has to do with the way objects inside NSTableCellViews are initialized, but I haven't found a real explanation. Any suggestions on how to solve this, or explanations as to why it's happening would be welcome. Thanks!
Here's an image of how the NSTableView is set up (with 3 rows):
If you are using XIB files to layout the views, the initialiser method being called is initWithCoder:
I saw this answer of how to create a placeholder for UITextView.
I took the following steps:
Add to the .h class the declaration:
#interface AdjustPhotoViewController : UIViewController<UITextViewDelegate>
Added the method:
- (BOOL) textViewShouldBeginEditing:(UITextView *)textView
{
NSLog(#"%d",[textView tag]);
if ([textView tag]==1){
campaignTitle.text = #"";
}else{
campaignDescription.text = #"";
}
return YES;
}
But I don't see that the method is being invoked!
What am I missing?
textView is already delegated via the storyboard to the view
SOLVED:
The problem was that it wasn't delegated. Although I was using storyboard - it was only an outlet, not a delegate.
Remember that if you are using storyboard, you need to delegate also from the text view to the orange button of the view! not only the other way
What am I missing?
Actually setting the delegate.
textView.delegate = self;
Merely conforming to a protocol won't magically make your object into the delegate of an arbitrary object; that's just a formal thing, and anyways, how on Earth would the UITextField know which particular instance of the class it has to assign its delegate?
I'm trying to make a subclass of the UIBarButtonItem class. The button is added in the nib file and I set its class to my custom class in the interface builder. Now if this was a UIView class or subclass I would have override the - (id)initWithCoder:(NSCoder *)decoder method to start the extra customization, however UIBarButtonItem lacks such a method. I tried to override its -(id)init method but with no success, it doesn't get called. My question, where should I start my customization? What method do I need to override?
It's because you use IB. When you create an object in IB it does not call the init method for the class, it uses the archive version of the object. So to make custom initializations use this method instead:
-(void)awakeFromNib{
//initialize here
}