UINavigationController：调用viewDidLoad但不影响UI

Question

I have this in the App Delegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:    (NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    self.window.backgroundColor = [UIColor whiteColor];

    OneViewController *vc = [[OneViewController alloc] initWithNibName:@"OneViewController" bundle:nil];
    UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:vc];

    [self.window setRootViewController:nav];
    [self.window makeKeyAndVisible];
    return YES;
}

and this in OneViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 44)];
    [button setTitle:@"Hi" forState:UIControlStateNormal];
    [self.view addSubview:button];
}

But when I run the app in the simulator, the OneViewController screen is blank. It has a xib file which is just the default blank xib.

Answer 1

在iOS 7中，按钮的背景颜色和标题的字体颜色都是白色的。您可以将按钮的背景颜色或按钮的标题颜色设置为黑色以使按钮显示吗？