Question

I have a simple piece of code that places a background image on the tabBar.

UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"tabBG.png"]];
[self.tabBarController.tabBar insertSubview:imageView atIndex:0];
[imageView release];

This works fine in iOS 4 but when testing in iOS 5, it doesn’t work.

I’m trying to do the following:

UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"tabBG.png"]];

NSString *reqSysVer = @"4.3";
NSString *iOSVersion = [[UIDevice currentDevice] systemVersion];

if ([iOSVersion compare:reqSysVer options:NSNumericSearch] !=NSOrderedDescending) {
    // code for iOS 4.3 or below
    [self.tabBarController.tabBar insertSubView:imageView atIndex:0];
}
else {
    // code for iOS 5
    [self.tabBarController.tabBar insertSubView:imageView atIndex:1];
}

[imageView release];

Alas, this isn’t working… Can anyone offer a solution?

Answer 1

iOS5 offers the UIAppearance Proxy.

Also, it’s best practice to switch your code based on the capability (in this case it’s respondsToSelector) instead of iOS version – that’s a fragile assumption (who’s to say it doesn’t change in the future).

You can set it for just that instance or globally for all tab bars:

// not supported on iOS4    
UITabBar *tabBar = [tabController tabBar];
if ([tabBar respondsToSelector:@selector(setBackgroundImage:)])
{
    // set it just for this instance
    [tabBar setBackgroundImage:[UIImage imageNamed:@"tabbar_brn.jpg"]];

    // set for all
    // [[UITabBar appearance] setBackgroundImage: ...
}
else
{
    // ios 4 code here
}