I'm working with a simple iPad application, and I've got a simple problem. I'm setting up a custom UIView; here's my initWithFrame:
- (id)initWithFrame:(CGRect)frame
{
if ((self = [super initWithFrame:frame]))
{
self.backgroundColor = [UIColor colorWithWhite:.4 alpha:1.0];
....
}
return self;
}
The problem is that when the app starts, in this view the background color is not applied, even though the rest of the init is running (controls are added, etc). When I rotate the device though, the background color is applied, and will remain applied for the lifetime of the app. I think I'm missing a layout command somewhere, but I'm not sure where. Any ideas?
EDIT 2
Here's the call to init the view. These methods are in my ViewController.
-(id)initWithFrame:(CGRect)_rect
{
rect = _rect;
if(self = [super init])
{
......
}
return self;
}
- (void)loadView
{
[super loadView];
myView = [[MyView alloc]
initWithFrame:rect];
self.view = myView;
}
The -initWithFrame: is called by Interface Builder, but not by the NSCoder instance that unarchives your view from the nib file at runtime. Instead, the unarchiving mechanism calls -initWithCoder:, so your view subclass would need to do something like this:
- (id)initWithCoder:(NSCoder *)decoder
{
if ((self = [super initWithCoder:decoder]))
{
self.backgroundColor = [UIColor purpleColor];
// Do other initialization here...
}
return self;
}
Try to change the background in the viewDidLoad method?
Mmmm
If you don't have the call method (wich alloc your UIView) we won't be able to help you.
It can be because your uiview frame isn't set up correctly.
Or because you don't call initWithFrame after alloc but you cal init function.
So give us more information if you want be helped :-)
Good luck !
Related
I've seen this question posted before but I cannot find the answer..
As expected, drawRect gets called automatically when the program launches. However when I call [self setNeedsDisplay] drawRect does not get called anymore and I cannot understand the reason why...
//DrawView.m
[self setNeedsDisplay];
-(void)drawRect:(CGRect)rect{
NSLog(# "Called_1");
//DRAW A PATH
}
Maybe using self is incorrect. I have also tried using DrawImage but still it doesn't work.
//DrawView.h
#interface DrawView : UIView {
UIImageView *drawImage;
}
//DrawView.m
-(id)initWithCoder:(NSCoder *)coder
{
self = [super initWithCoder:coder];
if (self) {
drawImage = [[UIImageView alloc] initWithImage:nil];
drawImage.frame = CGRectMake( 0, 0, self.frame.size.width, self.frame.size.height );
[self addSubview:drawImage];
}
return self;
}
Usually when you want to have a view redraw you should call:
[self setNeedsDisplay: YES];
Granted I have never build on iOS, on OSX this code works every time. Also, for example, if you want your delegate to call a redraw for a view named someView:
[someView setNeedsDisplay: YES];
Note: that YES is a macro defined by obj-c that is just a value of 1.
I have this cascade :
Somewhere in the app
- (void) go
{
MyCustomViewController* controller = [[MyCustomViewController alloc] init];
controller.delegate = self;
[controller run];
}
in MyCustomViewController
- (id) init
{
// there is an if statement here in real to choose another XIB if needed
// but I only display here the code that is called in my tests
self = [super initWithNibName:#"MyXIB" bundle:nil];
if (!self) return nil;
self.delegate = nil;
return self;
}
- (void) run
{
// do things with self.view
}
MyCustomViewController inherits GenericWindowController
in GenericWindowController
/*- (id) initWithNibName:(NSString*)nibNameOrNil bundle:(NSBundle*)nibBundleOrNil
{
if (!(self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil])) return nil;
self.view.userInteractionEnabled = NO; // THE APP CRASHES HERE ! self.view is nil
...
return self;
}*/
// METHOD created following first answers : NOT CALLED
- (void) viewDidLoad
{
self.view.userInteractionEnabled = NO;
// and many other things done with self.view
}
MyXIB has its File's owner set to MyCustomViewController and the view is connected.
All files are included and checked into the project.
GenericWindowController is designed to make some standard stuff.
MyCustomViewController extends this stuff to work with a custom View, as designed in MyXIB.
Why self.view is nil in GenericWindowController ?
Why viewDidLoad is not called ?
A view controller should not try to access its view in initWithNibName:bundle:. It should wait until viewDidLoad.
self.view is only valid after viewDidLoad -- in init... it is still nil.
Incredible !!! The problem was because of a missing localization for the XIB. Added the localization, and no problem anymore.
I am trying to push an opengl UIView to my navigation controller like this
GraphViewController *gvc = [[GraphViewController alloc] initWithTicker:[listOfItems objectAtIndex:indexPath.row]];
[self.navigationController pushViewController:gvc animated:YES];
[gvc release];
The initWithTicker method looks like this
-(id) initWithTicker:(NSString*)ticker{
self = [super initWithNibName:nil bundle:nil];
if (self) {
self.title = ticker;
EAGLView *eagl = [[EAGLView alloc] initWithFrame:[UIScreen mainScreen].bounds];
eagl.animationInterval = 1.0 / 60.0;
[eagl startAnimation];
self.view = eagl;
}
return self;
}
When I go back and forward in my UINavigationController, the drawView method (in EAGLView) keeps looping. Furthermore, if I pushViewController again, the first one does not stop and a new one is created! I've tried making this an instance variable so only one is created and it has the same effect. I would be grateful if anyone has insight as to why this is happening
sergio Suggestion:
-(id) initWithTicker:(NSString*)ticker{
self = [super initWithNibName:nil bundle:nil];
if (self) {
self.title = ticker;
}
return self;
}
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
eagl = [[EAGLView alloc] initWithFrame:[UIScreen mainScreen].bounds];
self.view = eagl;
}
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
eagl.animationInterval = 1.0 / 60.0;
[eagl startAnimation];
[super viewDidLoad];
}
same behaviour.
---This is how I fixed my drawView looping problem--
-(void)viewDidAppear:(BOOL)animated {
[eagl startAnimation];
[super viewDidAppear:animated];
}
-(void)viewDidDisappear:(BOOL)animated {
[eagl stopAnimation];
[super viewDidDisappear:animated];
}
--Craigs solution --
if(graphView == nil){
graphView = [[GraphViewController alloc] initWithTicker:[listOfItems objectAtIndex:indexPath.row]];
}else{
[graphView release];
graphView = [[GraphViewController alloc] initWithTicker:[listOfItems objectAtIndex:indexPath.row]];
}
Are you creating a new GraphViewController every time you want to push one onto your navigation stack? If so, it doesn't really matter how you're handling the creation of your EAGLView instance variable, since you're never going to be interacting with that view controller again anyway.
For example:
User taps something, a new GraphViewController is pushed on the stack
User goes back, this view controller continues to run
Return to 1. and repeat (thus creating a SECOND GraphViewController, and then a third, and then a fourth... etc.)
What you should probably be doing is maintaining your GraphViewController as an instance variable, and only creating it once. This will ensure that you're in turn only creating one EAGLView.
if (_graphViewController == nil) {
_graphViewController = [[GraphViewController alloc] initWithTicker:[listOfItems objectAtIndex:indexPath.row]];
}
[self.navigationController pushViewController:_graphViewController animated:YES];
Then, be sure to release the view controller in your dealloc method if you're going to be maintaining it as an ivar.
Would you try executing this code of yours:
EAGLView *eagl = [[EAGLView alloc] initWithFrame:[UIScreen mainScreen].bounds];
eagl.animationInterval = 1.0 / 60.0;
[eagl startAnimation];
self.view = eagl;
inside of loadView? I am not sure about why your view is behaving like you say, but that is the place where you are supposed to build your UI... so it might make a difference...
Furthermore, I would call [eagl startAnimation]; only in viewDidLoad...
Hope it helps...
I am using presentModalDialog to show a viewcontroller's view however the viewDidLoad never gets called?!
Is there any method that is called where I can place my logic that fills and configures the view?
EDIT:
It's a bit difficult to put a small amount of code, you kind of need to see it all, but here goes:
I have 2 nibs and 2 view controllers (portrait-mainvc/landscape) which both inherit from 1 baseclass which has the logic and the iboutlets. This is to allow me to re-use code. When the orientation changes in the main controller, it switches between the 2 controllers (modal dialog) which in turn use their respective nib's however they all use the same base code to configure the UI items.
#implementation HomeViewControllerBase
- (void)configureBestSellItems
{
[self startRetrievingRegions];
// load all the images from our bundle and add them to the scroll view
// NSUInteger i;
for (int i = 0; i <= 150; i++)
{
NSString *imageName = #"tempImage.jpg";
UIImage *image = [UIImage imageNamed:imageName];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
// setup each frame to a default height and width, it will be properly placed when we call "updateScrollList"
CGRect rect = imageView.frame;
rect.size.height = kScrollObjHeight;
rect.size.width = kScrollObjWidth;
imageView.frame = rect;
imageView.tag = i; // tag our images for later use when we place them in serial fashion
[self.bestSellScrollView addSubview:imageView];
[imageView release];
}
[self layoutScrollImages]; // now place the photos in serial layout within the scrollview
}
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad
{
[super viewDidLoad];
[self configureBestSellItems];
}
#end
#interface HomeViewController : HomeViewControllerBase
{
}
#interface HomeViewController_Landscape : HomeViewControllerBase
{
}
#implementation HomeViewController
//This works for portrait
- (void)viewDidLoad
{
[super viewDidLoad];
}
#end
#implementation HomeViewController_Landscape
//This does not work
- (void)viewDidLoad
{
[super viewDidLoad];
}
//This works as suggested
- (void)awakeFromNib
{
[super configureBestSellItems];
}
#end
You can try these in your viewcontroller:
-(void)awakeFromNib
{
[super awakeFromNib];
// your code here
}
or
-(void) viewWillAppear:(BOOL)animated{
[super viewWillAppear:animated];
// your code here
}
However, you should try to find why viewDidLoad is never called. You can also check this
link.
You may have a custom function in there named presentModalDialog:, as searching apple's docs doesn't have that function. You're calling a custom function that loads a Xib.
I'm doing the same thing.
You want this:
[self presentModalViewController:controller...
ViewDidLoad is called by Controllers, if the awakeFromNib is being called, you're probably getting, by itself, the view.
It's a common problem in objective c:
you should review the flowing:
1-initiation of the view controller you should initialize it in the right way in app delegate.
2-review the file owner of the view it must be the right class which usually the same name of uiview.
i've create a UIButton subclass for my app and i need to manually reposition the titleLabel to be about 1/4 of the button's height. this post; http://forums.macrumors.com/showthread.php?t=763140 appears to directly address the same issue, and the solution is simple and perfectly understandable. however, i have failed to implement this because my override of layoutSubviews is never called. my button is static, so layoutSubviews only need be called the first time, but it never is. my code:
#interface MyButton : UIButton {}
#implementation MyButton
- (id)initWithFrame:(CGRect)frame
{
self = [[UIButton buttonWithType:UIButtonTypeRoundedRect] retain];
[[self layer] setCornerRadius:14.0f];
[[self layer] setBorderWidth:3.0f];
[[self layer] setMasksToBounds:YES];
[self setBackgroundColor:[UIColor redColor]];
[self setFrame:frame];
return self;
}
- (void)layoutSubviews
{
NSLog(#"layout subs\n");
[super layoutSubviews];
}
#end
moving the label would be no problem, but layoutSubviews is never called. i've also tried adding layoutIfNeeded, but it made no difference. what's even weirder, is i've tried to call [self layoutSubviews] directly from the constructor but layoutSubviews is still not called!. i'm starting to think this might even be a bug in SDK 3.1.3
can anyone help?!
In layoutSubviews, you can do layout changes to your subviews. Make sure that inside the method:
√ Call [super layoutSubviews]
x Do not change value or rect of self.frame here. If you do so, it would recursively call layoutSubviews.
√ Make sure you only change frame of its subviews.
From UIView Class Reference
to answer my own question, it seems i was subclassing incorrectly. taking the following approach results in layoutSubviews being called correctly:
+ (id)buttonWithFrame:(CGRect)frame {
return [[[self alloc] initWithFrame:frame] autorelease];
}
- (id)initWithFrame:(CGRect)frame {
if (self = [super initWithFrame:frame])
{
...
[self setFrame:frame];
}
return self;
}
hope that helps others