I have a custom view which contains two UILabel. I want to customize their fonts before so I did that in initWithCoder method.
#implementation HomeTitleView
#synthesize ticketLabel;
#synthesize monthLabel;
- (id) initWithCoder:(NSCoder *)aDecoder{
self = [super initWithCoder:aDecoder];
if (self) {
[monthLabel setFont:[UIFactory getFontForKey:#"home_month"]];
[ticketLabel setFont:[UIFactory getFontForKey:#"home_ticket"]];
}
return self;
}
#end
Unluckily, this did not work. Using a debugger, I found that monthLabel and ticketLabel are both nil. Anyone has idea how can I solve this? What callback or method I should implement so that I can access both of my labels?
You can't do that. The views don't exist yet. They are instantiated when the loadView method is called, which happens automatically when the view property is first accessed. If you want to manipulate your views after they have loaded, the correct method to use is viewDidLoad.
Edit: That's assuming you are working with a UIViewController class. If you are working with a UIView class, you can use awakeFromNib or didAddSubview:.
Do you ever assign monthLabel and ticketLabel to UILabel? Something like:
self.monthLabel = [[[UILabel alloc] init] autorelease];
self.ticketLabel = [[[UILabel alloc] init] autorelease];
If so, can you update your post with the code?
Related
I am subclassing an UIButton which is going to be present in all of my app's ViewControllers, kinda Navigation Button. I would like just to put it to my VC and apply custom class, without any code in ViewController itself. So, the questions:
1. is it possible?
2. I am using this code now in my UIButton custom class. What is wrong?:
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
[self addTarget:self action:#selector(didTouchButton) forControlEvents:UIControlEventTouchUpInside];
}
return self;
}
- (void)didTouchButton {
NSLog(#"YEAH, it works, baby!");
}
UPD: seems that even initWithFrame method is not being called at all.
Loading from the nib I think.The initWithFrame method doesn't work if not called programatically.
Try -awakeFromNib Method
See this question
I have a UITableViewController and don't want to use a storyboard.
As far as I know, the UITableViewController takes care of initialising the UITableView, connecting it to its dataSource and delegate. This works very well in my case.
I would now like to change the class of the UITableView to a custom class (BVReorderTableView). This would be easily done in IB. However, once I do this programmatically, my UITableView is empty, that is it seems to be disconnected from its source and delegate.
Here is what I do in my init of the UIViewController:
-(id)init
{
self = [super initWithStyle:UITableViewStyleGrouped];
if (self) {
// Custom initialization
self.tableView = [[BVReorderTableView alloc] initWithFrame:self.view.bounds style:UITableViewStyleGrouped];
self.tableView.dataSource = self;
self.tableView.delegate = self;
}
What am I doing wrong?
You should implement this in viewDidLoad instead of init, because of the ViewController lifecycle. At viewDidLoad he already has all of the objects that are going to get used, which isn't necessarily true during init.
You can check this question for more information on ViewController life cycles.
:)
Please set your UITableView in viewDidLoad method not in initmethod. In init method view will initialize itself before subviews contained within it.
Hope this helps
I am new to iOS programming. I have created ViewController with MKMapView element, and I wanted to set delegate [mapView setDelegate:self]
First I done it in method initWithNibName:bundle: like:
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
[[self map] setDelegate:self]];
UITabBarItem *item = [[UITabBarItem alloc] init];
[item setTitle:#"Map"];
[self setTabBarItem:item];
}
return self;
}
In this case MKMapView did not send me any messages, but when I placed setting delegate message to viewDidLoad method, it worked fine.
Could someone explain me why it was not working when setting delegate message was in initWithNibName:bundle?
Views do not get loaded in initWithNibName, it just initializes your viewcontroller class and load the xib file which contains your view details.
When viewcontroller calls viewDidLoad, you will have all your view objects allocated and initialized.
In your case, when you setDelegate in initWithNibname, you are calling it on a nil value, so nothing get set, but in viewDidLoad mapView is allocated and initialized, so it works fine.
For a deeper insight refer:
http://developer.apple.com/library/ios/#featuredarticles/ViewControllerPGforiPhoneOS/ViewLoadingandUnloading/ViewLoadingandUnloading.html
Beautiful explanation here: What is the process of a UIViewController birth (which method follows which)?
Looking to understand the iOS UIViewController lifecycle
http://thejoeconwayblog.wordpress.com/2012/10/04/view-controller-lifecycle-in-ios-6/
This line is your problem:
[self map]
In initWithNibName the map is not yet initialized and it returns nil.
In viewDidLoad the map is already initialized.
I am designing a Custom UIView for my app.
The UIView will comprise of below components:
UISearchbar
UITableView
My initialiser is below:
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
_searchBar = [[UISearchBar alloc]initWithFrame:CGRectZero];
_tableView = [[UITableView alloc]initWithFrame:CGRectZero];
_tableView.dataSource = self;
[super addSubView:_searchBar];
[super addSubView:_tableView];
// Initialization code
}
return self;
}
I am planning to set the frame of the _searchBar and _tableView in layoutsubviews method.
But I think think the way I have added the _tableView to super is wrong. Because the moment the _tableView is added to subview the data source methods of the _tableView will be triggered. And this happens even before the creation of the custom class itself.
Is this a correct design?
Can I add just _tableView alone in layoutSubviews as in below manner?
-(void)layoutSubViews{
//Adjust frame
[_tableView removeFromSuperView];
[self addSubView:_tableView];
}
You shouldn't be assigning the UITableViewDataSource in the view. It should be assigned in the ViewController.
You're right. There is no restriction on it. But your question is about design. Imagine something like this:
#implementation CustomViewController
- (void)loadView {
customView = [[CustomView alloc] initWithFrame:CGRectZero];
customView.tableView.dataSource = self;
customView.tableView.delegate = self;
}
With a ViewController, you can control when you initialize your custom view and control when its tableView loads the data. While you can certainly put all of this code into your customView, you will be running into problems much worse than the one you are asking about now.
You should definitely add it in init, because layout sub-views will get called each time you view will resize and will need to re-layout its sub-views.
Layout subviews method is strictly use as a callback telling you that your view will layout, and is used as an override point for any additional layout you wish to make.
Also, as an additional note, it's not good design adding the view using super.
I am wanting to create a custom UIView class that will show a dynamic number of UISegmentedControl objects depending on some input. For example, if a client has 5 products in their cart, the UIView should generate 5 UISegmentedControl objects that I will then link with each item.
The problem I am having is getting this to work in a UIView. Here is what I have done so far. I am successfully able to create a UISegmentedControl object and display it programmatically within my main UIViewController. I don't get any display when adding it to my UIView class. Here is the implementation code for the UIView class:
#import "ajdSegmentView.h"
#implementation ajdSegmentView
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
NSArray *itemArray = [NSArray arrayWithObjects:#"Yes", #"No", nil];
UISegmentedControl *button = [[UISegmentedControl alloc] initWithItems:itemArray];
button.frame = CGRectMake(35,44, 120,44);
button.segmentedControlStyle = UISegmentedControlStylePlain;
button.selectedSegmentIndex = 1;
[self addSubview:button];
}
return self;
}
#end
I created a new UIView object via Storyboard and placed it inside the UIViewController scene. I made sure to set the class from the generic UIView class to my new custom class. I added and outlet for the UIView in my UIViewController class. Here is the code inside the implementation of UIViewController:
#import "ajdViewController.h"
#interface ajdViewController ()
#end
#implementation ajdViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.segmentView = [[ajdSegmentView alloc] init];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
That's all I have tried. I have been searching through a lot of pages and trying to implement this without asking here, but I seem to be looking in the wrong places.
First you need to check ajdSegmentView is UIVIew or UIViewController. It is fine if it is UIView. If it is type of UIViewController then you need to add this line while adding Segment.
[self.view addSubview:button];
In place of:
[self addSubview:button];
And One more thing You forget to add this View to your main after allocating so You can declare like this:
objajdSegmentView = [[ajdSegmentView alloc] init];
[self.view addSubview:objajdSegmentView.view];
I have just added this thing. i got result like this way.
Hope this will work for you.
You're initializing your custom view using the init method, but your initialization for ajdSegmentView is in your initWithFrame: method (which in your case is not getting called).
So replace:
self.segmentView = [[ajdSegmentView alloc] init];
with:
// Change the frame to what you want
self.segmentView = [[ajdSegmentView alloc] initWithFrame:CGRectMake(0,0,100,40)];
Also don't forget to add your view to the view controller's view also.
[self.view addSubview:self.segmentView];
Unless this view is being created with interface builder, in which case you will need to override initWithCoder: in your ajdSegmentView class.
I'm not familiar with Storyboard though, so maybe I'm missing something, but in a standard scenario what I said above will solve your problem.