将初始视图控制器连接到选项卡视图控制器

Question

我想将登录场景用作初始视图控制器并将其连接到选项卡视图控制器。我不断收到以下错误消息：

终止应用程序由于未捕获的异常 'NSInvalidArgumentException'，原因： ' - [UIViewController中的TabBar]：无法识别的选择发送到实例0x7fe85a560fd0'

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

@interface LogInViewController : UIViewController <UITextFieldDelegate> 
@property (weak, nonatomic) IBOutlet UITextField *txtUsername; 
@property (weak, nonatomic) IBOutlet UITextField *txtPassword; 

- (IBAction)sigininClicked:(id)sender; 

- (IBAction)backgroundTap:(id)sender; 
@end 


// AppDelegate.m 
// 

#import "AppDelegate.h" 

@interface AppDelegate() 

@end 

@implementation AppDelegate 

- (BOOL)application:(UIApplication *)application  didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 
{ 

// Assign tab bar item with titles 
UITabBarController *tabBarController = (UITabBarController *)self.window.rootViewController; 
UITabBar *tabBar = tabBarController.tabBar; 
UITabBarItem *tabBarItem1 = [tabBar.items objectAtIndex:0]; 
UITabBarItem *tabBarItem2 = [tabBar.items objectAtIndex:1]; 
UITabBarItem *tabBarItem3 = [tabBar.items objectAtIndex:2]; 
UITabBarItem *tabBarItem4 = [tabBar.items objectAtIndex:3]; 

tabBarItem1.title = @"Trucks"; 
tabBarItem2.title = @"Dashboard"; 
tabBarItem3.title = @"Map"; 
tabBarItem4.title = @"Settings"; 

[tabBarItem1 setFinishedSelectedImage:[UIImage imageNamed:@"iu.png"] 
      withFinishedUnselectedImage:[UIImage imageNamed:@"iu.png"]]; 
[tabBarItem2 setFinishedSelectedImage:[UIImage imageNamed:@"dashboard.png"] 
      withFinishedUnselectedImage:[UIImage imageNamed:@"dashboard.png"]]; 
[tabBarItem3 setFinishedSelectedImage:[UIImage imageNamed:@"globe.png"] 
      withFinishedUnselectedImage:[UIImage imageNamed:@"globe.png"]]; 
[tabBarItem4 setFinishedSelectedImage:[UIImage imageNamed:@"settings.png"] 
      withFinishedUnselectedImage:[UIImage imageNamed:@"settings.png"]]; 

return YES; 
} 

Answer 1

我我不是ios的专家，但这里是我最近编程的方式（没有故事板）在我的应用程序中。这是从我的appdelegate中提取的代码，但它也应该用于您的目的。

在.h文件：

@interface AppDelegate : UIResponder <UIApplicationDelegate, UITabBarControllerDelegate> 
     @property (strong, nonatomic) UITabBarController *tabBarController; 
     @property (strong, nonatomic) UIWindow *window; 

在.m文件：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { 
    self.window = [[UIWindow alloc]initWithFrame:[[UIScreen mainScreen]bounds]]; 
    self.tabBarController = [[UITabBarController alloc] init]; 
    FirstViewController *firstvc = [[FirstViewController alloc] init]; 
    SecondViewController *secondvc = [[SecondViewController alloc] init]; 
    tabBarController.viewControllers = @[firstvc, secondvc]; 
    self.window.rootViewController = tabBarController; 
} 

编辑：

在我的FirstViewController和SecondViewController .m文件：

- (instancetype)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil{ 
    self= [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; 

    if(self){ 
     self.tabBarItem.image = [UIImage imageNamed:@"img_vc1"]; 
     self.tabBarItem.title = @"My 1st View"; 
    } 
    return self; 
} 

Hope这有助于。