scrollViewDidEndDecelerating delivers AppDelegate different pointer than awakeFromNib - iphone

Question

edit 2
I found out it depends on the method used. I somehow lose the appdelegate pointer when I access it via scrollViewDidEndDecelerating instead of awakeFromNib. But I do need to use scrollViewDidEndDecelerating.
Can someone of you please fix this?
Works fine
- (void)awakeFromNib
{
AppDelegate *mainDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
NSLog(#"%#", [NSString stringWithFormat:#"%#", mainDelegate.content1]);
}
Crashes bad_access to mainDelegate.content1
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
AppDelegate *mainDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
NSLog(#"%#", [NSString stringWithFormat:#"%#", mainDelegate.content1]);
}
ORIGINAL QUESTION (I keep this for past-reference. Just read the above functions)
This problem regards stringWithContentsOfURL
The code below works, downloads HTMLstring to mainDelegate.content1 and shows it appropriately in UIWebView controller.myWebView. If I modify the function, so that I conduct the downloading process beforehand, let it be somewhere in AppDelegate.m, the program crashes upon processing mainDelegate.content1 in this very function.
Here goes the good code
- (void)ReloadView:(int)page{
MyViewController *controller = [viewControllers objectAtIndex:pageControl.currentPage];
mainDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
NSError * error;
NSURL * Tmpurl;
NSString *tmpContent;
NSString *urlAddress;
urlAddress = mainDelegate.TitleStrP1;
Tmpurl = [NSURL URLWithString:urlAddress];
tmpContent = [NSString stringWithContentsOfURL:Tmpurl encoding:NSUTF8StringEncoding error:&error];
maindelegate.content1 = [NSString stringWithString:tmpContent];
[controller.myWebView loadHTMLString:mainDelegate.content1 baseURL:nil];
}
And here what I am trying to do and what doesn't work. SomeFunction executes upon startup of the app. I checked the loaded value after downloading HTMLstring into content1 from the Internet site and html code indeed is there.
- (void)ReloadView:(int)page{
MyViewController *controller = [viewControllers objectAtIndex:pageControl.currentPage];
mainDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
//code had been removed here
[controller.myWebView loadHTMLString:mainDelegate.content1 baseURL:nil];
}
-(void)SomeFunction{
NSError * error;
NSURL * Tmpurl;
NSString *tmpContent;
NSString *urlAddress;
urlAddress = mainDelegate.TitleStrP1;
Tmpurl = [NSURL URLWithString:urlAddress];
tmpContent = [NSString stringWithContentsOfURL:Tmpurl encoding:NSUTF8StringEncoding error:&error];
maindelegate.content1 = [NSString stringWithString:tmpContent];
}
Your help is appreciated.
Thanks
EDIT:
AppDelegate.h
#import <UIKit/UIKit.h>
#class ContentController,MyViewController;
#interface AppDelegate : NSObject <UIApplicationDelegate>
{
...
NSString *content1;
NSString *content2;
}
...
#property (nonatomic, strong) NSString * content1;
#property (nonatomic, strong) NSString * content2;
AppDelegate.m
- (void)applicationDidFinishLaunching:(UIApplication *)application
{
content1 = [NSString stringWithString:#""];
content2 = [NSString stringWithString:#""];
NSError * error;
NSURL * Tmpurl;
NSString *tmpContent;
NSString *urlAddress;
urlAddress = TitleStrP1;
Tmpurl = [NSURL URLWithString:urlAddress];
tmpContent = [NSString stringWithContentsOfURL:Tmpurl encoding:NSUTF8StringEncoding error:&error];
content1 = [NSString stringWithString:tmpContent];
urlAddress = TitleStrP2;
Tmpurl = [NSURL URLWithString:urlAddress];
tmpContent = [NSString stringWithContentsOfURL:Tmpurl encoding:NSUTF8StringEncoding error:&error];
content2 = [NSString stringWithString:tmpContent];
...
}

Answer 1

Is your "Content1" property in the appDelegate using "strong"? Also, to use properties, you should be using lower class as the setter needs to capitalize the variable name (setContent1). That is
#property (nonatomic, strong) NSString *content1;
EDIT:
[[UIApplication sharedApplication] delegate] will always work. By bad, you did not say if there is a value there or not (that is, is it nil). So one of these is happening.
1) your AppDelegate object is getting released and dealloced. I'm not sure how you would do this but its possible.
2) You have told UIApplication to create a delegate in main.m, in the fourth parameter of "UIApplicationMain()", but have also specified a NIB in your .plist file and that nib ALSO has a AppDelegate object in it and is wired to the UIApplication as a delegate. If you are using a NIB the property attribute for AppDelegate better be STRONG as its not retained by the UIApplication (it says this in the delegate property of UIApplication).
3) If the "delegate" property is nil, then someone has set it to nil.
Think about it - the UIApplication delegate gets set very early, otherwise you would never get the launched message.
So you need to add a "dealloc" method to your app delegate and log if that happens. You can also add a simple "init" method that also logs when AppDelegate is created - then see if my suspicion is correct.