iOS 7如何修改状态栏文本颜色？

在没有使用 UIViewController-based status bar 时，使用如下设置方法：

// Setting the statusBarStyle does nothing if your application is using the default UIViewController-based status bar system.
@property(readwrite, nonatomic) UIStatusBarStyle statusBarStyle NS_DEPRECATED_IOS(2_0, 9_0, "Use -[UIViewController preferredStatusBarStyle]") __TVOS_PROHIBITED;

• (void)setStatusBarStyle:(UIStatusBarStyle)statusBarStyle animated:(BOOL)animated NS_DEPRECATED_IOS(2_0, 9_0, "Use -[UIViewController preferredStatusBarStyle]") __TVOS_PROHIBITED;

没有使用 UIViewController-based status bar 时，用

// Setting the statusBarStyle does nothing if your application is using the default UIViewController-based status bar system.
@property(readwrite, nonatomic) UIStatusBarStyle statusBarStyle NS_DEPRECATED_IOS(2_0, 9_0, "Use -[UIViewController preferredStatusBarStyle]") __TVOS_PROHIBITED;
- (void)setStatusBarStyle:(UIStatusBarStyle)statusBarStyle animated:(BOOL)animated NS_DEPRECATED_IOS(2_0, 9_0, "Use -[UIViewController preferredStatusBarStyle]") __TVOS_PROHIBITED;

在格式中将UIViewControllerBasedStatusBarAppearance 设置为 YES
在viewDidLoad中做[self setNeedsStatusBarAppearanceUpdate];
添加如下代码
-(UIStatusBarStyle)preferredStatusBarStyle{
    return UIStatusBarStyleLightContent;
}