xcode - 通过在 xcode 中单击按钮启用和禁用选项卡栏项目？

Question

我有 5 个标签栏项目。第一个将是登录页面。当用户尚未登录时，其他选项卡 bat 项目将被禁用，但当用户通过单击导航项按钮登录时，所有其他 4 个选项卡 bat 项目将被启用。

我已经搜索过但一无所获...... :(

这是我的代码:

MainTabViewController.h
#import <UIKit/UIKit.h>

@interface MainTabViewController : UITabBarController
@property (retain, nonatomic) IBOutlet UITabBar *MainTabBar;

@end


MainTabViewController.m

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.


    UITabBarItem *tabBarItem = [[MainTabBar items] objectAtIndex:1];
    [tabBarItem setEnabled:FALSE];


}

LoginViewController.h



#import <UIKit/UIKit.h>

@interface LoginViewController : UIViewController
@property (retain, nonatomic) IBOutlet UITextField *CustomerUsername;
@property (retain, nonatomic) IBOutlet UITextField *CustomerPassword;
- (IBAction)ResignKeyboardClicked:(id)sender;

@end

LoginViewController.m

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    UIBarButtonItem *btnGo = [[UIBarButtonItem alloc] initWithTitle:@"Login"     style:UIBarButtonItemStyleBordered target:self action:@selector(loginAction)];
    self.navigationItem.rightBarButtonItem = btnGo;

}

- (void) LoginAction {
     AppDelegate *passData = (AppDelegate *)[[UIApplication sharedApplication] delegate];

        if ([CustomerUsername.text isEqualToString:@""] || [CustomerPassword.text     isEqualToString:@""]) {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"alert" message:@"Please Fill     all the field" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
        [alert show];

        return;
    }
    // i will use a code from connect to DB tutorial
    NSString *strURL = [NSString stringWithFormat:@"http://localhost:8888/Staff.php?userName=%@&password=%@",CustomerUsername.text, CustomerPassword.text];

    // to execute php code
    NSData *dataURL = [NSData dataWithContentsOfURL:[NSURL URLWithString:strURL]];

    // to receive the returend value
    NSString *strResult = [[NSString alloc] initWithData:dataURL encoding:NSUTF8StringEncoding];


    if ([strResult isEqualToString:@"1"])
    {
        //MainTabViewController *main = [[MainTabViewController alloc] initWithNibName:nil bundle:nil];
        //UITabBarItem *tabBarItem = [[main.MainTabBar items] objectAtIndex:1];
        //[tabBarItem setEnabled:TRUE];

        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Success" message:@"You are now Logged In" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
        [alert show];

    return;
    }
    else
    {
        // invalid information
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"alert" message:@"Invalide Information" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
        [alert show];

        return;

    }
}

现在我的代码只禁用其他 4 个标签栏项目，但我不知道在用户登录时启用所有标签栏项目的方法。

请帮忙？

谢谢! :D

Answer 1

我不得不说，我是 iOS 开发的初学者，我想我可以帮助你。

在 Storyboard 中创建一个 TabBarController 和所有其他 UIViewController。将它们链接到 TabBarController 并向它们添加分配类。在您的情况下，其中一个 UIViewController 将被称为 LoginViewController。现在，当您的应用程序启动时，LoginViewController 必须是第一个选项卡，您只需添加此代码即可禁用这些选项卡:

[[[[self.tabBarController tabBar]items]objectAtIndex:1]setEnabled:FALSE];
[[[[self.tabBarController tabBar]items]objectAtIndex:2]setEnabled:FALSE];
[[[[self.tabBarController tabBar]items]objectAtIndex:3]setEnabled:FALSE];

同样，您可以通过以下方式启用它们:

[[[[self.tabBarController tabBar]items]objectAtIndex:1]setEnabled:TRUE];
[[[[self.tabBarController tabBar]items]objectAtIndex:2]setEnabled:TRUE];
[[[[self.tabBarController tabBar]items]objectAtIndex:3]setEnabled:TRUE];

所以你的 LoginAction 函数看起来像这样:

- (void) LoginAction {
     AppDelegate *passData = (AppDelegate *)[[UIApplication sharedApplication] delegate];

        if ([CustomerUsername.text isEqualToString:@""] || [CustomerPassword.text     isEqualToString:@""]) {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"alert" message:@"Please Fill     all the field" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
        [alert show];

        return;
    }
    // i will use a code from connect to DB tutorial
    NSString *strURL = [NSString stringWithFormat:@"http://localhost:8888/Staff.php?userName=%@&password=%@",CustomerUsername.text, CustomerPassword.text];

    // to execute php code
    NSData *dataURL = [NSData dataWithContentsOfURL:[NSURL URLWithString:strURL]];

    // to receive the returend value
    NSString *strResult = [[NSString alloc] initWithData:dataURL encoding:NSUTF8StringEncoding];

    if ([strResult isEqualToString:@"1"]) {
        //MainTabViewController *main = [[MainTabViewController alloc] initWithNibName:nil bundle:nil];
        //UITabBarItem *tabBarItem = [[main.MainTabBar items] objectAtIndex:1];
        //[tabBarItem setEnabled:TRUE];

        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Success" message:@"You are now Logged In" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
        [alert show];

        [[[[self.tabBarController tabBar]items]objectAtIndex:1]setEnabled:TRUE];
        [[[[self.tabBarController tabBar]items]objectAtIndex:2]setEnabled:TRUE];
        [[[[self.tabBarController tabBar]items]objectAtIndex:3]setEnabled:TRUE];

        return;
    }
    else {
        // invalid information
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"alert" message:@"Invalide Information" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
        [alert show];

        return;
    }
}

我希望它有帮助:D