修改nav的控件阴影等效果 传递字典

   self.nav = [[[NavViewController alloc] initWithRootViewController:self.viewController] autorelease];
   [self.nav.navigationBar setBackgroundImage:[UIImage imageNamed:@"navbg"] forBarMetrics:UIBarMetricsDefault];
   NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:[UIColor whiteColor],UITextAttributeTextColor,[UIColor blackColor],UITextAttributeTextShadowColor,[UIFont boldSystemFontOfSize:20.0],UITextAttributeFont,CGSizeMake(0, -1.0),UITextAttributeTextShadowOffset, nil];

   self.nav.navigationBar.titleTextAttributes = dict;

那个statusbar字体是黑色的，我怎么设置成白色的？

在viewDidLoad里面加   [self setNeedsStatusBarAppearanceUpdate]; 

再重写- (UIStatusBarStyle)preferredStatusBarStyle {
    return UIStatusBarStyleLightContent;
}不过iOS7以下不能用