I'm brand new to iPhone programming. I've tried some tutorials and such and now I'm trying to do a simple project to get my feet wet. And of course I have having issues getting it to do what I want. I started it by using a Navigation project. I didn't want the UITableView though I just want normal buttons that lead to the next page. Although when I tried to get rid of the UITableView I think I did it wrong so now it isn't working when I am setting up the next view.
Here is the .h (the red underline is under the MPHViewController in both places) Oh and what it wants to do is make both those UIViewController.
#import <UIKit/UIKit.h>
#import "MPHViewController.h"
#interface RootViewController : UIViewController {
MPHViewController *mphViewController;
}
#property(nonatomic,retain) MPHViewController *mphViewController;
#end
I'm thinking where I mainly messed up was in the .m (I think) I took out all the code that had to do with the UITableView and simply put this in (wasn't sure what else should be placed there).
- (UIViewController *)viewControl:(UIView *)view
{
}
Sorry for being a pain I just don't know any better way of learning how to do this other then just trial and error.
It might not be able to find the definition for your custom class.
In xcode under the project setting -> build phases, make sure the MPHViewController.m is included in the list of source files to be compiled.
Also, make sure in your MPHViewController.h that your subclassing UIViewController properly:
#interface MPHViewController : UIViewController
{
// ....
}
Make sure you synthesize it in the .m
#synthesize mphViewController;
Related
I am trying to use storyboards in my application. I began well, I have added two view controllers with a button to go from the first to the second.
The problem is in this second view controller: the objects I add on it and link with the code do not work. When I set a breakpoint in the view controller code, the 'self.property' is set to nil, whereas it should be instantiated by the storyboard.
I have been looking for an answer for hours, and I really don't understand the problem, since all the rest seems to be good.
I have tried to write the property in the code (strong/nonatomic, nonatomic/retain and even weak/nonatomic), to link the object directly to the code so that it creates the property automatically, but I never get anything else than "nil" with breakpoints.
viewController.h:
#interface NMLoadingViewController : UIViewController
{
__weak IBOutlet UIProgressView *imageProcessingProgressView;
}
#property (weak, nonatomic) IBOutlet UIProgressView *imageProcessingProgressView;
#end
.m:
#synthesize imageProcessingProgressView;
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
// Custom initialization
NSLog(#"INIT.");
}
(amont other lines of irrelevant code)
If I set the breakpoint to the "INIT." line, my imageProcessingProgressView is nil. I can't see a reason for that, I guess I have missed a very little detail...
(Note that I have tried this with other objects, like a UILabel, but it did not work either. Stranger, when I had two objects, one of them had an adress which was not nil, but still it was corrupted and did not show the right object.)
Edit: It was a lot of trouble for nothing... The problem is about the Variable View in XCode, which show my variable to "nil", whereas a log shows me a correct object...
Remove this...
{
__weak IBOutlet UIProgressView *imageProcessingProgressView;
}
...and make the property strong.
Change your log message to...
NSLog(#"INIT: %#", self.imageProcessingProgressView);
...and see if you still have a problem. If you do, then take another look at your storyboard connections.
Make sure NMLoadingViewController is the class on your viewController
First try out the answer by #Eric because I do believe that is the real issue.
Also, make sure that you are actually using the interface builder to hook the controls back to the view controller. This is done by dragging a line from the control back to the property of the view controller.
My problem is that I cannot access any of the controls in a view defined using interface builder. This is the .h code for the Navigation bar (as an example):
#import <UIKit/UIKit.h>
#interface myController : UIViewController {
IBOutlet UINavigationBar *tTitle;
}
#property (nonatomic,retain) UINavigationBar *tTitle;
#end
The implementation (.m) is:
#import "myController.h"
#implementation myController
#synthesize tTitle;
- (void)dealloc {
[tTitle release];
[super dealloc];
}
- (void)viewDidLoad {
tTitle.topItem.title=#"This is my title";
}
In viewDidLoad tTitle (and my other outlets) are always 0x0. I have omitted the two text fields and the button for brevity.
This exact code works in another view in the app without issue. In IB I right click on the file owner icon and it shows my outlets correctly (and the single button action). Yet at run time - nada. I click the button and no response. The title is still the default title. I cannot set the text fields text property because the fields are all 0x0.
The view is linked to the view controller. As near as I can tell everything is identical between the two views that are doing the same thing. Obviously something is awry, but I can't figure it out. Any help would be appreciated.
Okay. I did the ROI and figured it would be easier to delete and recreate the view (one control at a time) in an attempt to see where it was going awry. The answer is the title bar title set worked from the get-go. I have no idea why the other class didn't work. But discretion is the better part of valor in this situation. The new class is working fine. Thanks for everyone's input.
I'm trying to build a simple TableView program struture.
It seems to work fine, but if I scroll the list to high or to low, the app crashes without any console error and the trace into the debugger does not help.
You can see it by yourself looking at the project I put at : http://shine.free.fr/tmp/myTestApp.zip
Can you help me :
to know what goes wrong
to know how I may find what goes wrong without having to ask each time. Usually I check my connection, lokk for compile errors, look into the console and try to debug, but there, nothing helps me.
Thank you for your help
The problem is that your ListController object is not retained when it is loaded from nib file, so it is not guaranteed that it will be valid after nib is loaded (and in fact it is not). To solve your problem add an outlet for ListController property and define retaining property for it. Here's FenetreListeController.h that fixes your problem:
#import <UIKit/UIKit.h>
#class ListeController;
#interface FenetreListeController : UIViewController {
IBOutlet ListeController* listController;
}
#property (nonatomic, retain) ListeController* listController;
#end
You will also need to set outlet connection in IB and synthesize property in .m file
For more information about how objects are loaded from xib files check "The Nib Object Life Cycle" section from "Resource Programming Guide"
I am writing a library to be used by developers for the iPhone (similar to the way that OpenFeint is implemented) and I am trying to create a ViewController with an associated XIB so that I can instantiate it in my code with
SplashScreenViewController *splashScreenViewController = [[SplashScreenViewController alloc] init];
UIWindow *topApplicationWindow = [self getTopWindow];
[topApplicationWindow addSubview:splashScreenViewController.view];
However, while this works with simple controls (UIButtons, etc), nothing shows up with my SplashScreenViewController. SplashScreenViewController is very simple:
#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>
#interface SplashScreenView : UIViewController {
}
#end
and the implementation is empty. In my View XIB (SplashScreenView.xib), I have tried setting the File's Owner's class to SplashScreenViewController which didn't work, then I tried it the way I've seen it done in OpenFeint which is to add a View Controller in IB and make the main UIView a child of it and make it of class SplashScreenViewController instead. That also does not work (does not display).
I'm wondering if anyone has a good idea for what I might be missing, or if someone can recommend a walkthrough for creating new ViewControllers the way that I'm attempting to.
Thanks!
Try 2 things :
Call initWithNibName not just init. Maybe the OpenFeint you were talking about were overriding the init to call initWithNibName , that's why you don't see it.
Set SplashScreenViewController as your file owner, and connect his view outlet to your
view in IB.
Hope it helps.
Instead of [splashScreenViewController alloc], try [SplashScreenViewController alloc]. I'm surprised you didn't get a compiler warning.
I am new to the iPhone SDK and am trying to create 3 views and switch between them. Data will come from a server and I will basically be showing 1 view and caching the other two. So far I am just trying to create a view and display it at run-time. My code is listed below. It shows only a blank screen and I think I am missing a key concept. Any Help?
#import <UIKit/UIKit.h>
#import "ImageViewController.h"
#interface Test5ViewController : UIViewController
{
IBOutlet UIView *rootView;
ImageViewController *curImage;
ImageViewController *nextImage;
ImageViewController *prevImage;
}
#property(nonatomic,retain) IBOutlet UIView *rootView;
#property(nonatomic,retain) ImageViewController *curImage;
#property(nonatomic,retain) ImageViewController *nextImage;
#property(nonatomic,retain) ImageViewController *prevImage;
#end
and
- (void)loadView
{
self.curImage = [[ImageViewController alloc]initWithNibName:#"ImageView" bundle:[NSBundle mainBundle]];
UIImage *pic = [UIImage imageNamed:#"baby-gorilla.jpg"];
[self.curImage assignImage:pic];
self.rootView = self.curImage.view;
}
and
#import <UIKit/UIKit.h>
#interface ImageViewController : UIViewController
{
IBOutlet UIImageView *image;
}
-(void)assignImage:(UIImage *)screenShotToSet;
#property(nonatomic,retain) IBOutlet UIImageView *image;
#end
Welcome to the iPhone SDK!
In general, there are two ways to get any view displayed.
First, and most commonly, you use a NIB file created by the Interface Builder. This is usually the easiest way to get started and I would recommend it for what you're trying to do here. It's too lengthy to describe all the steps you need to do for what you have here, but basically start in xcode by creating a new file and selecting "user interfaces" and choose View XIB. This will create a basic NIB file (they're called NIBs rather than XIBs for historical reasons). The first step in interface builder is to change the class name of the "File's Owner" to your UIViewController subclass (Test5ViewController). You can then drop anything that IB will allow into the view window or even replace the pre-supplied view object with one of your own. And here's the trick: make sure the view outlet (supplied by the UIViewController superclass) is connected to a view. Once this is done, this view will be automatically loaded when your NIB is loaded. You can then just put your UIViewController subclass (Test5ViewController) in your MainWindow.xib NIB file to get it automatically loaded, and you're in business.
Now, the way you're doing it here is the second way. Some people like to code this way all the time and not user interface builder. And while it's definitely necessary sometimes and always more flexible, it makes you understand what is happening a bit better. There may be other things, but the main thing you're missing is that in your code above, you have nothing that is adding your view into the view hierarchy. You need to check first that you have an UIApplicationDelegate subclass and it needs to load your "root" UIViewController class. All initial project creation types in xcode do this (except Window-based application). It is code like:
[window addSubview:rootController.view];
Once this is done, if your view controller wasn't loaded by the NIB (described briefly above), your loadView method will be called, expecting you to build your own view hierarchy. Above, you created the view(s), but failed to put them in a hierarchy. You need something like:
[self.view addSubview:curImage.view];
No view will be rendered until added to the view hierarchy. Make sure to look up the UIView class in the documentation and understand the variety of ways to add and remove views to the view hierarchy.
A couple things I should warn you about:
* your code above is leaking. You need to review how objective-C properties work. There's lots on this site about it. More than I have time to write about here.
* don't create a rootView property in the case you have here. There already is one in the superclass (UIViewController). It's just 'view'. Use that for saving your root view.
I hope this helps you get started. It can be bewildering at first, but you'll soon get it going! I recommend building and rewriting and rebuilding a lot of sample code before you do your "real" application. The SDK has many great samples.