如何更改标签栏上的非活动图标/文本颜色？

在每个TabBar的每个第一个ViewController中：

- (void)viewDidLoad
{
    [super viewDidLoad];

    // changing the unselected image color, you should change the selected image 
    // color if you want them to be different
    self.tabBarItem.selectedImage = [[UIImage imageNamed:@"yourImage_selectedImage"]
    imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];

    self.tabBarItem.image = [[UIImage imageNamed:@"yourImage_image"] 
    imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
}

此代码的线索是'UIImageRenderingModeAlwaysOriginal'：

The clue of this code is 'UIImageRenderingModeAlwaysOriginal':

Apple文档的渲染模式：

UIImageRenderingModeAutomatic,          // Use the default rendering mode for the context where the image is used    
UIImageRenderingModeAlwaysOriginal,     // Always draw the original image, without treating it as a template
UIImageRenderingModeAlwaysTemplate,     // Always draw the image as a template image, ignoring its color information

要更改文字颜色：

在AppDelegate中：

In AppDelegate:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Add this if you only want to change Selected Image color 
    // and/or selected image text
    [[UITabBar appearance] setTintColor:[UIColor redColor]];

    // Add this code to change StateNormal text Color,
    [UITabBarItem.appearance setTitleTextAttributes:
    @{NSForegroundColorAttributeName : [UIColor greenColor]} 
    forState:UIControlStateNormal];

    // then if StateSelected should be different, you should add this code
    [UITabBarItem.appearance setTitleTextAttributes:
    @{NSForegroundColorAttributeName : [UIColor purpleColor]} 
    forState:UIControlStateSelected];

    return YES;
}