Xcode render the .PNG images all white

Question

I'm importing a .PNG into xcode. The image has transparency. When it's rendered on a button from the ID, all the content of the image except the transparency turns to white.

Is this a known issue? Is it because of the way I save the .PNG?

Thanks for the help!

Does the .png look correct when viewing it elsewhere (such as Preview)? If you post your relevant code, it might be easier to spot the issue. — AtkinsonCM, Feb 10 '12 at 21:28
Wait a minute - are you talking about UIButton or UIBarButtonItem? It sound like the latter... does the image show properly if you load it into a UIImageView? — Rok Jarc, Feb 10 '12 at 22:02
yes, the image looks just fine in the preview (before importing the image in xcode), but not in the interface builder, where I set the image on the button properties — Vince, Feb 10 '12 at 22:11
Yes, it is a UIBarButtonItem and it does display correctly if it's UIImageView — Vince, Feb 10 '12 at 22:11

AtkinsonCM · Answer 1 · 2012-02-16T00:12:05.700

To display an image in a UIBarButtonItem, you need to create a UIButton with the image, then add that button to the UIBarButtonItem. Otherwise you just get the outline, as you mentioned.

So:

// Initialize the UIButton with your image
UIImage *myImage = [UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"someImage" ofType:@"png"]];
UIButton *myButton = [[UIButton alloc] init];
[myButton setImage:myImage forState:UIControlStateNormal];

//Then create the UIBarButton
UIBarButtonItem *aBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:aButton];

score 0 · Answer 2 · answered Feb 10 '12 at 22:33

That's just how images work on UIBarButtonItems and UITabBarItems: the image you supply is only used as a transparency mask. You can either use an UIImageView/UIButton instead to display your image (as AtkinsonCM has suggested), or create an image that will work as a mask.

I personally feel it's usually better to play by Apple's rules, unless you have a compelling reason not to (e.g. the user experience will be significantly improved).

Xcode render the .PNG images all white

2 Answers2