iOS标签栏控制器：未选择标签项的首页消息

Question

I have built an iOS application based on a tab bar controller with several view controllers .

When the application starts, the view of the first view controller appears (normally).

I would like to print a "home message" that is not related to a view controller of the tab bar. When the user clicks on a tab, then the associated view is printed.

Is this possible?

Answer 1

You just need to add a view to the tab bar's view hierarchy. Remove it when you're done.

Something like this adds a label view on top of the tab bar's view:

# somewhere in your .m:
UILabel *label;

# later on:
- (void)viewDidLoad
{
    [super viewDidLoad];
    label = [[UILabel alloc] initWithFrame:CGRectMake(20, 20, 140, 44)];
    [label setText:@"Hello"];
    [self.view addSubview:label];
}

I did it in viewDidLoad , but you can do it wherever it makes sense to your code.

Then, you can make it disappear with something like this:

# even further along:
- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController
{
    [label removeFromSuperview];
}

This will make it disappear whenever any tab is touched.