UIImageView is not always shown

4
votes

I'm debugging a problem with an imageView not being shown.

imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:imageName]];
NSLog(@"imageView right after initialization is: %@", imageView);

imageView.frame = CGRectMake(2, 0, 316, 45);
imageView.layer.zPosition = zPos;
NSLog(@"imageView after running the setters: %@", imageView);

[self.view addSubview:imageView];

The weird part is that sometimes the imageView gets displayed, sometimes it's not (about 75% of the time it's displayed).

imageView is not accessed anywhere except the code above.

What I noticed is that when the imageView is not displayed, the first log statement shows that:

imageView right after initialization is: <UIImageView: 0x9eaa760; frame = (0 0; 0 0); userInteractionEnabled = NO; layer = <CALayer: 0x9ec04a0>>

When the image view is displayed:

imageView right after initialization is: <UIImageView: 0xaa61ad0; frame = (0 0; 644 88); opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0xaa61330&rt;&rt;

EDITED: I ran tens of tests, the imageView always behaves the same: when it is not shown, the initial frame is (0 0; 0 0). When it's not, it's always some other value.

P.S. I'm not using ARC.

3
iosobjective-cuiimageview
You set frame using CGRectMake(2, 0, 316, 45) in your code, why in logs it shows frame = (0 0; 644 88)? – Mil0R3
What method is the above code in? Is it in viewDidLoad? This smells like an auto-layout issue ... – David Doyle
have you tried running the same code with a different image name? do you get the exact same results? have you tested with loading huge images, very small images? tests like these can help isolate the problem at least.. – abbood
@Veelian, it shows frame = (0 0; 644 88) in the first log statement, when the frame is not yet set. – Sergey
@DavidDoyle, yes, it's in the viewDidLoad! – Sergey

3 Answers

2
votes

Why don't you set the frame first and set the image next?

 imageView = [UIImageView alloc]initWithFrame:CGRectMake(0,0,35,35)];
 [imageView setImage:[UIImage imageNamed:@"img.png"]];
2
votes

In your log of the UIImageView it show frame = (0 0; 0 0); This means that the view will not be shown since it has a height and width of 0. Which indicates that the image has no size or is nil.

The cause of this is most probably because the image your are trying to load is not found: You should check wether the image is found or not:

UIImage *image = [UIImage imageNamed:imageName];
if (!image) {
   NSLog(@"Image could not be found: %@", imageName);
}

imageView = [[UIImageView alloc] initWithImage:image];

Meaning that even if you change the frame you will still see nothing since there is no image loaded.

1
votes

In addition to rckoenes answer you must always check if the image exists within your bundle path first:

NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *documentsDirectory 
        = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)
             objectAtIndex:0];
    NSString *path = [documentsDirectory stringByAppendingPathComponent:imageName];
    if([fileManager fileExistsAtPath:path])
    {
       UIImage *image = [UIImage imageNamed:imageName];
       if (!image) {
          NSLog(@"Image could not be found: %@", imageName);
       }

       imageView = [[UIImageView alloc] initWithImage:image];
    } else {
       NSLog(@"%@ is not included in the app file bundle!", imageName);
    }

that way you'll know if the problem is b/c you don't have the file in the first place.. or b/c there is something wrong with file that prevents iOS from loading it.