IOS 7 更改导航栏文字到白色

To hide status bar in any viewcontroller:

-(BOOL) prefersStatusBarHidden
{
    return YES;
}

To change the status bar text to white color.

set UIViewControllerBasedStatusBarAppearance to NO on .plist file first, then added this method:

-(UIStatusBarStyle)preferredStatusBarStyle{
    return UIStatusBarStyleLightContent;
}