Question

I am trying change an UIImageView from other viewControllers, but I don’t know why image does not change !! here is my code :

#import "ViewController.h"

@class ViewController;
@interface CoverGallery : UIViewController {

    ViewController *mainViewController;
}
@property (nonatomic,retain) ViewController *mainViewController;
- (IBAction)img1;

.m

- (IBAction)img1 {

    mainViewController.coverArt.image = [UIImage imageNamed:@"coverDefault.png"];
    [self dismissModalViewControllerAnimated:YES];

}

There is an UIImageView called coverArt in MainViewController , thanks

Here is my button action which switch between views :

ViewController (My First view)
.h

@interface ViewController : UIViewController {
ViewController *mainViewController;

}

@property (nonatomic, retain) ViewController *mainViewController;


.m :

@synthesize mainViewController;


- (void) CoverGallery {

    CoverGallery *gallery = [[CoverGallery alloc] initWithNibName:@"CoverGallery" bundle:nil];
    gallery.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal; 
    [self presentModalViewController:gallery animated:YES];

//here is the problem, compiler gives me the mainViewController is not the property of CoverGallery
gallery. mainViewController = self;
    ;

}

Answer 1

How are you initializing the property mainViewController? You need set it as the MainViewController by setting its property when you present the modal view.
I imagine your doing this in the MasterViewController:

  CoverGallery *gallery = [[CoverGallery alloc]initWithNibName:@"CoverGallery" bundle:nil];
    gallery.masterViewContrller = self; //Set it here
    [self presentModalViewController:gallery animated:YES];

I fixed a typo..
and this:

ViewController *mainViewController;

should be:

MainViewController *mainViewController;

but you need to Import it in the same header file.