Need help: add UIImageView as a subview

[situee]

I simply want to add a UIImageView to my view in a view-based application.
but the picture does not show up. only black screen and a window "GDB loading stack frames..." comes out.

Thank you for reading this post and help me with this problem.

// File name: AddSubviewViewController.h
#import <UIKit/UIKit.h>
@interface AddSubviewViewController : UIViewController {
UIImageView *myImageView;
}
@property (nonatomic, retain) UIImageView *myImageView;
@end

// AddSubviewViewController.m
#import "AddSubviewViewController.h"
@implementation AddSubviewViewController
@synthesize myImageView;

- (void)loadView {}

- (void)viewDidLoad {
[super viewDidLoad];
UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"banana1.png"]];
myImageView = imageView;
myImageView.frame = CGRectMake(0,0,61,80);
[imageView release];
[self.view addSubview:myImageView];
}

- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}

- (void)dealloc {
[super dealloc];
}
@end

[dragon_tenvel]

Since nobody replied, I can try a few things :

Are you sure you added the banana1.png to your project?

Instead of the line

myImageView = imageView;

Try to put :

self.myImageView = imageView;

If it doesn't work, why don't you create a nib from interface Builder and init your view controller with this nib?

[Sicga]

This is the code I've used to add subviews to an imageView. I'm no expert but maybe it might help you.


UIImageView *subview = [[UIImageView alloc] initWithFrame:CGRectMake(15.0f, 43.0f,261.0f, 276.0f)];


[subview setImage:[UIImage imageNamed:@"banana.png"]];
[imageView addSubview:subview];
[subview release];

[situee]

dragon_tenvel , Sicga , thank you very much for the reply

I figured out the problem. I removed the empty method "loadView" and it works now. Maybe there is sth overrided by the empty method

Actually I don't know what's the difference between putting codes in
loadView and viewDidLoad.

but I still have a question on when I can release sth allocated by [class-name alloc]. sometime the program terminated when I try to release something. should I push all the releases in the dealloc method?

[Sicga]

From what I understand, anything you @synthesize in your implementation file (.m) you release in -(void)dealloc, I assume that is what you mean by [class.name alloc], anything you initialise in a function such as the viewDidLoad etc e.g NSMutableArray *array the contents of which are passed to the synthesized variable is normally released in that function, usually just before [super viewDidLoad];

Here's an example:

in .h file

@interface RootController: UITableViewController
{
NSArray *timezones
}

in .m file

@implementation RootController
@synthesize timezones;

-(void)viewDidLoad
NSMutableArray *array = [[NSMutableArray alloc] init];
self.timezones = array;
[array release];
[super viewDidLoad];
}

-(void)dealloc {
[timezones release];
[super dealloc];
}

I'm not 100% sure of this but that seems to be what more experienced iPhone programmers do.

[situee]

Thank you! your comments really help me a lot to understand when to release. I found that in some sample codes from Apple there is no [super viewDidLoad] in the viewDidLoad method. It should be fine releasing instances at the end of the function where they were initialized.

Originally Posted by Sicga

From what I understand, anything you @synthesize in your implementation file (.m) you release in -(void)dealloc, I assume that is what you mean by [class.name alloc], anything you initialise in a function such as the viewDidLoad etc e.g NSMutableArray *array the contents of which are passed to the synthesized variable is normally released in that function, usually just before [super viewDidLoad];

Here's an example:

in .h file

@interface RootController: UITableViewController
{
NSArray *timezones
}

in .m file

@implementation RootController
@synthesize timezones;

-(void)viewDidLoad
NSMutableArray *array = [[NSMutableArray alloc] init];
self.timezones = array;
[array release];
[super viewDidLoad];
}

-(void)dealloc {
[timezones release];
[super dealloc];
}

I'm not 100% sure of this but that seems to be what more experienced iPhone programmers do.

[dragon_tenvel]

If you try to release an autorelease object your programm will quit. For example, don't try to release an NSString object