自定义UITabBar背景图像在iOS 5及更高版本中无效

Question

我有一段简单的代码,可以在tabBar上放置背景图像.

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

这在iOS 4中运行良好,但在iOS 5中测试时,它不起作用.

我正在尝试执行以下操作:

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];

唉,这不行......有人能提供解决方案吗？

Answer 1

iOS5提供UIAppearance Proxy.

此外,最佳做法是根据功能(在这种情况下,它是respondsToSelector)而不是iOS版本切换代码 - 这是一个脆弱的假设(谁说它将来不会改变).

您可以仅为该实例设置它,也可以为所有标签栏全局设置它:

// 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
}

Answer 2

//---- For providing background image to tabbar

UITabBar *tabBar = [tabBarController tabBar];
if ([tabBar respondsToSelector:@selector(setBackgroundImage:)])
{
    // ios 5 code here
    [tabBar setBackgroundImage:[UIImage imageNamed:@"PB_MD_footer_navBg_v2.png"]];

}
else
{
    // ios 4 code here

    CGRect frame = CGRectMake(0, 0, 480, 49);
    UIView *tabbg_view = [[UIView alloc] initWithFrame:frame];
    UIImage *tabbag_image = [UIImage imageNamed:@"PB_MD_footer_navBg_v2.png"];
    UIColor *tabbg_color = [[UIColor alloc] initWithPatternImage:tabbag_image];
    tabbg_view.backgroundColor = tabbg_color;
    [tabBar insertSubview:tabbg_view atIndex:0];

}