iOS - 检查选择了哪个 UITabBar 选项的简单方法

Question

我的目标是制作一个 if/else 语句，以便我可以说:如果选择了 TabBarItem，则将 SelectedImageTintColor 设置为该颜色。

我是 ObjC 的新手，不确定如何实现 if 语句。这是我的 viewDidLoad:

- (void)viewDidLoad
{
[super viewDidLoad];

UITabBarItem *item0 = [self.tabBar.items objectAtIndex:0];
item0.image = [[UIImage imageNamed:@"red.png"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];


UITabBarItem *item1 = [self.tabBar.items objectAtIndex:1];
item1.image = [[UIImage imageNamed:@"yellow.png"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];

UITabBarItem *item2 = [self.tabBar.items objectAtIndex:2];
item2.image = [[UIImage imageNamed:@"green.png"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];

UITabBarItem *item3 = [self.tabBar.items objectAtIndex:3];
item3.image = [[UIImage imageNamed:@"black.png"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];

[[UITabBar appearance] setSelectionIndicatorImage:
 [UIImage imageNamed:@"item.png"]];


}

如您所见，我为每个 TabBarItems 指定了单独的图像，我想让高亮颜色与图像匹配(因此 red.png 为红色高亮，yellow.png 为黄色等)

如何实现这个 if/else 语句？同样，我想检查 indexPath (0-3)，然后为 tabBarItem 设置自定义 setSelectedImageTintColor。对我来说，另一个选择是完全删除突出显示，如果这样更实用的话。

Answer 1

- (void)viewDidLoad
{
[super viewDidLoad];

UITabBarItem *item0 = [self.tabBar.items objectAtIndex:0];
item0.image = [[UIImage imageNamed:@"red.png"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];


UITabBarItem *item1 = [self.tabBar.items objectAtIndex:1];
item1.image = [[UIImage imageNamed:@"yellow.png"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];

UITabBarItem *item2 = [self.tabBar.items objectAtIndex:2];
item2.image = [[UIImage imageNamed:@"green.png"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];

UITabBarItem *item3 = [self.tabBar.items objectAtIndex:3];
item3.image = [[UIImage imageNamed:@"black.png"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];

[[UITabBar appearance] setSelectionIndicatorImage:
 self.tabBar.selectedItem.image];


}

如果您希望在切换标签页时更新图像:

在你的 .h 文件中，你会有这样一行:

@interface MyClass : UIViewController

改成

@interface MyClass : UIViewController <UITabBarDelegate>

当然，用您的类(class)名称替换 MyClass。

在你的 viewDidLoad: 中，添加这一行:

self.tabBar.delegate = self;

在您的 .m 文件中，像这样实现 tabBar:didSelectItem::

- (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item {
    [[UITabBar appearance] setSelectionIndicatorImage:item.image];
}