I noticed that sometimes on viewDidLoad I got the view size right. Sometimes I don't.
For example
- (void)viewDidLoad
{
[super viewDidLoad];
self.pullToRefreshController = [self.pullToRefreshController initWithDelegate:self];
PO(self.view);
PO(self.view.superview);
PO(self.view.superview.superview);
PO(self.view.superview.superview.superview);
while(false);
}
-(void)viewWillLayoutSubviews
{
PO(self.view);
PO(self.view.superview);
PO(self.view.superview.superview);
PO(self.view.superview.superview.superview);
while (false);
}
at viewDidLoad the size of self.view is still 320 to 480. At viewWillLayoutSubviews that have been fixed.
I wonder what happen in between and where should I initialize stuffs? Or what stuffs should be in viewDidLoad and what stuffs should be in viewWillLayoutSubviews?
viewDidLoad is a good place to create and initialize subviews you wish to add to your main view. It is also a good place to further customize your main view. It's also a good place to initialize data structures because any properties should have been set on the view controller by the time this is called. This typically only needs to be done once.
viewWillLayoutSubviews is where you position and layout the subviews if needed. This will be called after rotations or other events results in the view controller's view being sized. This can happen many times in the lifetime of the view controller. You should only layout the views here.
Related
I have a header that I would like to add to every view in my program. Rather than manually do this I've been trying to find a way to insert this "header view" above every view that gets loaded. In the sample below, I tried using the insertSubView method but this inserts the entire view and not just the tiny bit of header content I'm interested in.
[self.view insertSubview:self.headerController.view aboveSubview:self.indexController.view];
[self.view insertSubview:self.indexController.view atIndex:0];
Does anyone know how to do this correctly? I'm using Xcode 5.
You're inserting the views of the headerController and indexController on your other view controllers' views. Generally, though, you want to be careful about keeping your view hierarchy synchronized with your view controller hierarchy. The importance of this is discussed in some detail in WWDC 2011 video Implementing UIViewController Containment.
So, generally you'd instantiate the appropriate indexController and headerController, call addChildViewController, add the subviews, and then call didMoveToParentViewController for each of those two view controllers. For more information, see Creating Custom Container View Controllers section of the View Controller Programming Guide for iOS. But you app's view controllers might do something like:
HeaderController *headerController = ... // instantiate however is appropriate
[self addChildViewController:headerController];
headerController.view.frame = [self frameForHeaderController]; // define the frame/constraints as appropriate
[self.view addSubview:headerController];
[headerController didMoveToParentViewController:self];
You'd then repeat that process for the indexController.
Just make sure to (in addition to doing the custom container calls) either set the frame of the view controller's frame or define auto-layout constraints that will dictate the placement of the view (like you do for any programmatically added view). If you don't specify the frame, it may well end up being CGRectZero, which is obviously not what you intended.
You might, though, consider flipping this around. Make a custom container view controller that includes your header and any other UI elements that persist for every view. Then make your app's view controllers as child controllers of that container "parent" view controller. If either the header controller's view or the index controller's view navigates your app between various content view controllers, this sort of structure might make more sense.
I think if you watch that WWDC video and/or review the Creating Custom Container View Controllers, this will make more sense.
I'd suggest to create a base view from which you will subclass for every views that need this header.
You could have a BaseView.h that would look like:
#interface BaseView : UIView
#property (nonatomic) UIView *someHeaderView;
#end
And the implementation (.m) looking like this:
#implementation BaseView
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
self.headerView = [[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, CGRectGetWidth(frame), 150.0)];
[self.view addSubview:self.headerView];
}
return self;
}
#end
Then have every views that requires a header subclass it:
#interface SomeViewRequiringHeader : BaseView
#end
Try reversing the order of the two:
[self.view insertSubview:self.indexController.view atIndex:0];
[self.view insertSubview:self.headerController.view aboveSubview:self.indexController.view];
Also, since headerController is a UIViewController, it probably has a nib file with a default size of full screen. If you want to only be a certain height, you have to modify that nib file with the appropriate height.
I have a app out for testing right now that's almost completely done - just a few bug fixes left. Unfortunately, the customer decided that they'd like the entire main page of the app to be inside of a scroll view (so that there's more room for the table at the bottom). I already have everything set up and I don't really want to move everything and change references. Is there an easy way to change the class of the main view to a scroll view? I've already tried changing the class in IB and setting the class type in the init method. If there isn't I'll probably just throw the top section of the view into a nib file and load it as a custom cell.
-EDIT- I ended up changing the class type in IB and then doing
[(UIScrollView *) self.view setScrollEnabled:YES];
[(UIScrollView *) self.view setContentSize:CGSizeMake(0,2000)];
in viewDidLoad. Thanks for the help, wish I could accept all your answers.
When you are referring to [self view], I am going to assume you mean in a view controller. The view of a view controller can be any view that derives from UIView. Thus a scrollview is completely acceptable.
I don't really want to move everything and change references.
what would you have to move? why would you have to change references? Only thing you should need to do is add a scroll view to your view controller, set the view controllers view to it, and add the current view as a subview to the new scroll view. No references need to be changed, nothing has to be moved.
Refer to loadView method in documentation of view controller.
Here is a simple (untested!) example
- (void)loadView {
UIScrollView *scrollView = [[UIScrollView alloc] init] autorelease];
//Set the properties of scrollview appropriately....
self.view = scrollView;
}
Now the root view of your view controller will be a scroll view.
Note
- As the documentation states, do not do this if you are using interface builder to initialize your views/view controller. I could not tell from your description if this was the case or not. If it is, you should be able to change the view type in interface builder.
You need to set the contentSize property of your scrollview.
Since you are using IB, the easiest way to do this is to put all your UI elements into a view and add this single view to your scroll view. In the viewDidLoad method, set the content size of the scrollview to be the same size as the view that contains all your UI.
As an aside, there are much easier ways to reference views than walking down the view hierarchy, as you seem to be doing. viewcontroller.view.something.tableview. Add a connection to the tableview from your view controller in IB and it doesn't matter where that tableview is in the view hierarchy. You'll always be able to reach it from viewcontroller.tableview, no matter how you rearrange your nibs.
I think you have to use a pointer with proper type. Example for Google Maps: let's say you changed you base view's class to GMSMapView.
MapViewController.h
#property GMSMapView *mapView;
MapViewController.m
-(void)awakeFromNib{
[super awakeFromNib];
self.mapView = (GMSMapView*)self.view;
// ... etc.
}
Okay so I feel like there's something obvious I'm missing in this question. I've used makeFirstResponder throughout my code to move from textField 1 to 2, 2 to 3, etc. That seems to work as I want it to, yet when the new view is loaded, I want the cursor to be in textField1, and yet the following code does not place the cursor in textField1 upon load.
- (void) awakeFromNib{
[[[self view] window] makeFirstResponder:textField1];
}
I also tried setInitialFirstResponder, and that didn't have any effect either (I don't even think that would be right.) So, is it because it is in the awakeFromNib method? Can anyone tell me what I'm missing? Thanks in advance.
EDIT - My solution was differed slightly from the accepted answer so I thought I'd post my implementation. Because the view I wanted to set the first responder for was a subview added later (think the second screen of an application wizard), I simply added a setCursorToFirstTextField method:
- (void) setCursorToFirstTextField {
[[[self view] window] makeFirstResponder:textField1];
}
And made sure to call it after I had added the subview to the custom view on the original window.
Yes, you're right about the problem being the location of the method in awakeFromNib. If you log [self.view window] in your awakeFromNib, you'll see that it's NULL. I don't know how exactly you have things set up, but I'm guessing (if this relates to your WizardController question) that you're doing an alloc initWithNibName:bundle: in another class to create your view controller and then adding that controller's view to the view hierarchy. If you throw some logs in there, it will show you that awakeFromNib in the controller class is called after the alloc init, but before the view is added as a subview, so there is no window at that time. The way I got around this problem was to create a setup method in the view controller class (with the makeFirstResponder code in it), and call it from the class where you create the controller after you add it as a subview.
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
self.wizard = [[WizardController alloc] initWithNibName:#"WizardController" bundle:nil];
[self.window.contentView addSubview:wizard.view];
[self.wizard doSetup];
}
Two objective-c methods, -(void) viewDidLoad and -(void)loadView are methods called upon execution of a program but whats the different between them?
Do you mean viewDidLoad and loadView? viewDidLoad is a method called when your view has been fully loaded. That means all your IBOutlets are connected and you can make changes to labels, text fields, etc.
loadView is a method called if you're (typically) not loading from a nib. You can use this method to set up your view controller's view completely in code and avoid interface builder altogether.
You'll typically want to avoid loadView and stick to viewDidLoad.
Use -(void)loadView when you create the view. Typically usage is:
-(void)loadView {
UIView *justCreatedView = <Create view>;
self.view = justCreatedView;
}
Use -(void)viewDidLoad when you customize the appearance of view. Exapmle:
-(void)viewDidLoad {
self.view.backgroundColor = [UIColor blackColor];
...
}
i think you are talking about loadView and viewDidLoad.
loadView is a method that you not using a nib file - you use it to programmatically 'write' your interface
viewDidLoad fires automatically when the view is fully loaded. you can then start interacting with it.
more to read read in the discussion here iPhone SDK: what is the difference between loadView and viewDidLoad?
I set views programmatically. Here is how I do that. Let's say I have SettingsViewController.m
In this file I have two methods
-(void)loadView
{
UIView *view = [[UIView alloc] initWithFrame:[UIScreen mainScreen].applicationFrame];
self.view = view;
[view release];
}
-(void)didViewLoad
{
// In that method I create some buttons labels etc
}
Is my approach correct ? To create the view in loadView method and buttons, labels etc in viewDidLoad method
To be honest it doesn't really matter if you put the code for creating views in viewDidLoad or loadView. viewDidLoad is called after the view is loaded, so will even be called if you are instantiating from a XIB. So that's a good place to add extra views if you're using a XIB. If you're programatically creating the view like you are in loadView then you can put the creation of your buttons, labels, etc in loadView or viewDidLoad and it won't really make a difference - viewDidLoad is pretty much called straight after loadView runs anyway.
Personally if I'm creating a view programatically using loadView then I will put all of the view creation code in there rather than in viewDidLoad.