I have a view controller instance created with instantiateViewControllerWithIdentifier like this:
TBSCTestController* testController = [self.storyboard instantiateViewControllerWithIdentifier: #"OTP"];
TBSCTestController has an IBOutlet property named label which is hooked up with a label in the storyboard:
I want to modify the text of label using this code but nothing changes:
testController.label.text = #"newText";
[self.view addSubview: testController.view];
The testController is a valid instance but the label is nil.
What did i miss?
Your UILabel is nil because you have instantiated your controller but it didn't load its view. The view hierarchy of the controller is loaded the first time you ask for access to its view. So, as #lnafziger suggested (though it should matter for this exact reason) if you switch the two lines it will work. So:
[self.view addSubview: testController.view];
testController.label.text = #"newText";
As an example to illustrate this point, even this one would work:
// Just an example. There is no need to do it like this...
UIView *aView = testController.view;
testController.label.text = #"newText";
[self.view addSubview: testController.view];
Or this one:
[testController loadView];
testController.label.text = #"newText";
[self.view addSubview: testController.view];
Related
I just want to load a custom view (with xib) on a viewcontoller's xib or stroy board.What is the best practice to do the same.
I have used awakeAfterUsingCoder function code below.
(id) awakeAfterUsingCoder:(NSCoder*)aDecoder
{
BOOL theThingThatGotLoadedWasJustAPlaceholder = ([[self subviews] count] == 0);
if (theThingThatGotLoadedWasJustAPlaceholder)
{
CustomView* theRealThing = (id) [CustomView view];
theRealThing.frame = self.frame;
theRealThing.autoresizingMask = self.autoresizingMask;
return theRealThing;
}
return self;
}
but after using this function my awakeFromNib started calling multiple time.
Please sugegst.
The correct answer currently linked to is overly complicated and buggy, as you have found out. There is a much more standard and better way to do this:
Create an empty XIB
Add a UIView to your XIB so that it is the only top-level object (aside from the proxies First Responder and File's Owner)
Change the class of your new UIView to CustomView
Instantiate the XIB and retrieve your CustomView instance like so:
CustomView *view = [[UINib nibWithNibName:#"CustomView" bundle:nil] instantiateWithOwner:self options:nil][0];
Add it to your view hierarchy in your view controller's viewDidLoad method:
[self.view addSubview:view];
Be sure to override -initWithCoder: in your CustomView subclass in case you need to do any custom initialization. I know this is a lot, so please let me know of any if these steps confuse you or if you get stuck.
With two ViewControllers, MyView 1 and MyView 2, is there possible to add a subview to MyView2 from MyView1.m?
I have tried:
MyView2 * screen = [[MyView2 alloc]initWithNibName:nil bundle:nil];
[screen.view addSubView:mySubView];
But my new instance of MyView 2 has no connection to the 'visible' ViewController on MyView2, right?
To clarify, the ViewController that is showing, is MyView1. I want MyView1 to be able to add a subview to the MyView2 view.
Thanks
I think you're confusing viewControllers with views, or at least your question is. Maybe it's something like this you're looking for -
MyViewController2 *myViewController2 = [[[MyViewController2 alloc] initWithNibName:nil bundle:nil] autorelease];
[myViewController2.view addSubView:mySubView];
// add any other views to myViewController2's view
[self.view addSubView:myViewController2.view]; // adding the view to VC1's view
If you want to be able to continue adding stuff throughout MyViewController1, you should declare either myViewController2 or its view as a retained property.
You could have MyView1 controller save some information in a common object in your app so that when MyView2 reappears it can add the subview to its view if needed.
Assuming MyView2 is a subclass of UIViewController, there is no addSubView: method on the viewcontroller itself. Instead, you want to add the subView to your view controller's view, like this:
[screen.view addSubview:mySubView];
try this,
[MyView1.view addSubView:MyView2];
[self.view addSubview:MyView1];
I have a ViewController that responds to some touchEvents (touchesBegan, touchesMoved, etc...).
I've found that when I show this controller using presentModalViewController: it works just fine, but I'm trying to add it's View as a subview of another ParentViewController like so:
- (void)viewDidLoad
{
[super viewDidLoad];
//Add SubController
controller = [[SubViewController alloc] initWithNibName:#"SubViewController" bundle:nil];
controller.view.frame = CGRectMake(0, 30, 300, 130);
[view addSubview:controller.view];
[controller release];
}
When I do this, it gets added the parent view but it no longer responds to touch events. Is there a way to fix this?
Also, is there a better way to go about this? I know I probably could have used a View subclass for the child view, but it's supposed to use a Nib and I wasn't sure how to handle that without using a ViewController.
You're correct you should use a UIView subclass.
The easiest way to load it from a nib is to include the subview in your nib.
Just drop a UIView into the view connected to the original view controller.
Then with the view inside selected go to the identity inspector. It's the one that looks like a little ID card.
The very first field is called Custom Class.
Type the name of your UIView subclass here.
If you need a reference to this just create an IBOutlet in your original view controller and hook it up. That way you can set hidden = YES until you need it.
In your UIView subclass you might want to override
- (void)awakeFromNib
This will get called when the nib first unpacks.
for setting up any gesture recognizers, etc.
To load a nib directly into a view :
// Get the views created inside this xib
NSArray *views = [NSBundle mainBundle] loadNibNamed:#"myViewNib" owner:nil];
// There's probably only one in there, lets get it
UIView *myView = [views objectAtIndex:0];
// Do stuff . . .
[[self view] addSubview:myView];
You could try to call becomeFirstResponder in your subview and see whether it receives touchesBegan... It is probably so, but it will also possibly make the superview not receive touchesBegan if you require it...
Is it possible with a standard UINavigationController-rooted app, to have a single ADBannerView visible at the bottom of the screen, below the view hierarchy? That is, without modifying each view-controller/view that can be pushed to the root UINavigationController, can I have a global ADBannerView be visible?
I'm not sure how to set this up, either in IB or in code. Help?
I see similar questions with vague answers. I'm looking for a concrete example.
EDIT: The better way to do this in iOS5+ is likely to use view controller containment. That is, make a root controller that contains your ad and application controller (nav, tab, etc.).
I figured out a way to do this. Here is what I did:
For my first attempt I created a new view controller called AdBannerController. For its view I created a full-screen view and two subviews. The first subview (contentView) is for regular content, the second is the AdBannerView. I used an instance of this view controller as the view controller associated with the app window ( [window addSubview: adBannerController.view] ). Then I added my UINavigationController.view as a subview of adBannerController.view: [adBannerController.contentView addSubview: navigationController.view].
This mostly worked except that viewcontrollers pushed to the UINavigationController never got their will/did-load/unload methods called. Shucks. I read in a few places that this is a symptom of the UINavigationController view not being a direct descendant of the app window.
For my second attempt I took the same AdBannerController and derived it from UINavigationController. This time, I did the following in loadView:
- (void)loadView
{
[super loadView];
_contentView = [self.view retain];
self.view = [[[UIView alloc] initWithFrame: _contentView.frame] autorelease];
[self.view addSubview: _contentView];
_adView = [[ADBannerView alloc] initWithFrame: CGRectMake(0, _contentView.bounds.size.height, 320, 50)];
_adView.currentContentSizeIdentifier = ADBannerContentSizeIdentifier320x50;
_adView.delegate = self;
[self.view addSubview: _adView];
/* for visual debugging of view layout
[[_mainView layer] setCornerRadius: 6.0];
[[_mainView layer] setMasksToBounds: YES];
[[_mainView layer] setBorderWidth: 1.5];
[[_mainView layer] setBorderColor: [[UIColor grayColor] CGColor]];
*/
}
Notice what happens - I let the superclass UINavigationController construct its regular "content" view, but I swap it out and replace it with my own view which is a container for both the content and ad views.
This works pretty well. I'm also using three20 and there were a few things required to make this work with that setup, but not too bad.
I hope this helps someone!
In Apple's dev sample code the iAdSuite project contents projects that have this done for you. Highly recommended.
In my root view controller (w/ ADBannerViewDelegate) I setup my banner by adding it to the nav controller view, which keeps it on top at all times:
banner = [[ADBannerView alloc] init];
banner.delegate = self;
banner.frame = CGRectMake(0.0, 430.0, banner.frame.size.width, banner.frame.size.height);
[self.navigationController.view addSubview:banner];
Note you will have to comment out layoutAnimated in delegate method bannerViewDidLoadAd as it will try to move the ad view up:
- (void)bannerViewDidLoadAd:(ADBannerView *)banner
{
//[self layoutAnimated:YES];
}
I adapted the approach suggested in the iAdSuite given here
http://developer.apple.com/library/ios/#samplecode/iAdSuite/Introduction/Intro.html
I downloaded the code and focused on the 'tab' example. I copied over the BannerViewController.h/.m as is into my project.
I created all my views in the usual way with the storyboard approach. However, in my AppDelegate class I then accessed the already built tab bar - containing all the storyboard built viewControllers.
The AppDelegate class implements the TabBarControllerDelegate protocol:
#interfaceAppDelegate : UIResponder <UITabBarControllerDelegate, UIApplicationDelegate>
The AppDelegate implementation didFinishLaunchingWithOptions method grabs the pre-built tabBar, setting its delegate to self (e.g. the AppDelegate class).
-(BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:
// ----------------------------------------------------------
// Set the TabBarController delegate to be 'self'
// ----------------------------------------------------------
_tabBarController = (UITabBarController*)self.window.rootViewController;
// tabController.selectedIndex = [defaults integerForKey:kOptionLastTabSelectedKey];
_tabBarController.delegate = self;
// update tab bar per iAdSuite approach
[self updateiAd];
I then built a new set of controllers per the iAdSuite approach and reset the tab bar with these new tab bar items.
-(void)updateiAd {
NSArray* viewControllers = [_tabBarController viewControllers];
NSMutableArray*newViewControllers = [[NSMutableArray alloc] init];
BannerViewController*bvc=NULL;
for(UIViewController * vc in viewControllers) {
bvc = [[BannerViewController alloc] initWithContentViewController:vc];
[newViewControllers addObject:bvc];
}
// set the new view controllers, replacing the original set
[_tabBarController setViewControllers:newViewControllers];
}
This approach puts the same 'ad' at the bottom of each view, exactly as needed. I also had to set the view title in the viewDidLoad method of each custom viewController (somehow, setting it on the bar item didn't seem to work not did setting the image; the later may reflect an issue with my images however).
My original configuration was
TabViewController
NavController1 NavController2 NavController3 ...
| | |
CustomViewController1 CustomViewController2 CustomViewController3
My final configuration is now
TabViewController
NavController1 NavController2 NavController3 ...
| | |
iAdView1 iAdView2 iAdView3
| | |
CustomViewController1 CustomViewController2 CustomViewController3
In terms of view lifecycle, I should add that only the NavControllers are in existence at the time the updateiAd method is called.
The individual CustomViewControllers1/2/3/etc get created after the call completes.
I have a question about UIViewController's subview, I created a UIView subclass MainView, which has the exact size of the screen, I wonder which is a better way of adding MainView, consider the following factors:
1 As MainView has same size as the whole screen, the MainView itself may have subviews, but there is no views at the save level as MainView(ie I don't need to add other subviews to self.view).
2 If I use self.view = mainView, do I put the code in loadView(as the viewDidLoad method means the view(self.view) is already loaded)? I see the loadView method is commented out by default, if I add the code to this method, what other code do I need to put together(e.g. initialize other aspects of the application)?
3 If I add mainView via [self addSubview:mainView], are there actually two off screen buffer? One for self.view, one for mainView, both has same size as the screen and one is layered on top of the other(so it wastes memory)?
Thanks a lot!
I'm not sure I completely understand what you're asking, but I'll try to answer a few of the questions you have.
First of all, if you have multiple UIViews on the screen they are all loaded into memory. You have to do -removeFromSuperview and release them to get the memory back.
You can assign your UIView as the UIViewController's view. For example:
MainView *mainView = [[MainView alloc] initWithFrame:CGRectMake(320.0, 480.0)];
self.view = mainView;
[mainView release]; //since the .view property is a retained property
in that case, you have have the view's initialization code in the -init method. Just redefine it like:
- (id)initWithFrame:(CGRect)frame
{
if (self = [super initWithFrame:frame]) {
//initializations
}
return self;
}
You must implement loadView if you did initialize your view controller with a NIB.
UIViewController takes care of sizing its "main" view appropriately. This is all you need to do:
- (void)loadView
{
UIView* mainView = [[[UIView alloc] initWithFrame:CGRectZero] autorelease];
self.view = mainView;
}
I'd solve all of this by doing it in a xib! If you create a UIView in your xib, you can then change it's class (when you select the UIView there should be a text field in the Class Identity section of the Identity inspector* - type 'MainView' here!)
Then, create your view controller by calling
myViewController = [[MainViewController alloc] initWithNibName:#"MyNibName" bundle:nil];
That should solve your problems; it's the main subview of your view controller (directly accessable from self.view) and you don't need to worry about memory usage, there's only one view :)
Sam
NB * Click tools -> Identity Inspector. I didn't know it was called this until I had to write this answer!
Yes, the first code-snippet shown above is the "standard" approach, AFAIK, when not using (evil!) NIB files -- i.e. when alloc'ing your view in-code, via loadView.
Note it seems one can also get away with the following, instead of hard-coding the screen-rect size:
UIView *myView = [[UIView alloc] initWithFrame:[UIScreen mainScreen].applicationFrame];
self.view = myView;
[myView release];
Note you definitely want to do the [myView release] call since, indeed, as pointed out above, self.view (for UIView) is a retained property.
Cheers, -dk
Perhaps the most important thing to do is make sure you have the following:
self.view.userInteractionEnabled = YES;
While it might not be required all of the time, it fixes the issue where self.view is unresponsive. This issue pops up occasionally.