导航控制器.导航栏.alpha AppDelegate不工作

Question

我在iOS7中有一个问题我想在AppDelegate中设置导航栏的不透明度

self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
self.homeController = [[HomeViewController alloc] init];
UINavigationController *navigationController = [UINavigationController new];
// Set alpha not work in appDelegate
navigationController.navigationBar.alpha = 0.7f;    
self.window.rootViewController =  [navigationController initWithRootViewController:self.homeController];

Answer 1

当你尝试分配alpha值时，navigationBar没有初始化。按以下方式做:

UINavigationController *navigationController = [[UINavigationController alloc]initWithRootViewController:self.homeController];
// Set alpha not work in appDelegate
navigationController.navigationBar.alpha = 0.7f;    
self.window.rootViewController =  navigationController;