默認狀態欄為黑色，對于某些App不是很美觀，變成白色很簡單，只需要兩個步驟。
1.在Info.plist中添加新項目，View controller-based status bar appearance，Boolean值為No.
2.在AppDelegate的- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions方法中添加
[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent animated:NO];
2017.04.11更新
Swift版本為?
UIApplication.shared.statusBarStyle = UIStatusBarStyle(rawValue: 1)!
或者
UIApplication.shared.statusBarStyle = UIStatusBarStyle.init(rawValue: 1)!
)
