StatusBar

参考文档1
参考文档2
参考文档3
状态栏颜色分为两种：
UIStatusBarStyleDefault 黑色
UIStatusBarStyleLightContent 白色

设置状态栏颜色

1. info.plist 中
   View controller-based status bar appearance 设为 NO
2. AppDelegate中
   [UIApplication sharedApplication].statusBarStyle = UIStatusBarStyleDefault;
3. 个别VC状态栏修改

- (void)viewWillAppear:(BOOL)animated{
   [super viewWillAppear:animated]
   [UIApplication sharedApplication].statusBarStyle = UIStatusBarStyleDefault;
}
-(void)viewWillDisappear:(BOOL)animated{
   [super viewWillDisappear:animated];
   [UIApplication sharedApplication].statusBarStyle = UIStatusBarStyleLightContent;
}