Error When Using UIApplication sharedApplication?

Obviously, I'm new to iOS development, but I could really use somebody's help. I am building a tab bar application in which I am attempting to load .plists into drill-down table views. The problem is that I can't seem to get this method right, as I am trying to use the navigation controller for a tab in its ViewController. I'm positive that my error is in the second line.

A37dgAppDelegate *AppDelegate = (A37dgAppDelegate *)[[UIApplication sharedApplication] delegate];
AppDelegate.indNavControl *indNavControl;

Subsequently, I get some errors. Here is the code, and I'll point out where the errors are:

    if([Children count] == 0) {

    DetailViewController *dvController = [[DetailViewController alloc] initWithNibName:@"DetailView" bundle:[NSBundle mainBundle]];

    [self.indNavControl pushViewController:dvController animated:YES];//Property "indNavControl" not found on object of type "IndustriesViewController"
    [dvController release];
}
else {

    //Prepare to tableview.
    IndustriesViewController *indViewControl = [[IndustriesViewController alloc] initWithNibName:@"IndustryView" bundle:[NSBundle mainBundle]];

    //Increment the Current View
    indViewControl.CurrentLevel += 1;

    //Set the title;
    indViewControl.CurrentTitle = [dictionary objectForKey:@"Title"];

    //Push the new table view on the stack
    [self.indNavControl开发者_运维知识库 pushViewController:indViewControl animated:YES]; //Property "indNavControl" not found on object of type "IndustriesViewController"

    indViewControl.tableDataSource = Children;

    [indViewControl release];
}

}

Just to be clear, I have imported the header file of my App Delegate. Any help would be greatly appreciated :)

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The line AppDelegate.indNavControl *indNavControl; is wrong. I think you don't need this line at all. And while pushing new view controller you can directly use AppDelegate.indNavControl instead of self.indNavControl,

[AppDelegate.indNavControl pushViewController:...

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Your theory that the problem is in the second line is correct.

AppDelegate.indNavControl *indNavControl;

that line isn't really doing anything. You need a class where AppDelegate.indNavControl is.

You have a couple of options:

1) if you want indViewControl to be a 'public' property

* in your IndustriesViewController.h, move the declaration of indViewControl there.

@interface
{
    WhateverClass *indNavControl;
}

@property (retain) WhateverClass*indNavControl;
@end

2) if you want a private property then add an empty category at the top of your .m with the ivar and property declaration from above.

What the compiler is complaining about is trying to access a property that doesn't exist.

calling self.whateverIvar requires an @property definition.

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first create the instance of the appdelegate like and then you can access, whatever variables you have declared in appdelegate as property,synthesize.There is no need to create seperate variable of indNavControl.