在Flutter中，例如iOS的状态栏中的时间、网络信号等字体的颜色修改有以下两个方式：
在 system_chrome.dart文件中有两段代码，用来更改不同的状态栏字体颜色。

介绍

1. 字体颜色白色

/// System overlays should be drawn with a light color. Intended for
  /// applications with a dark background.
  static const SystemUiOverlayStyle light = SystemUiOverlayStyle(
    systemNavigationBarColor: Color(0xFF000000),
    systemNavigationBarDividerColor: null,
    statusBarColor: null,
    systemNavigationBarIconBrightness: Brightness.light,
    statusBarIconBrightness: Brightness.light,
    statusBarBrightness: Brightness.dark,
  );

2. 字体颜色黑色

/// System overlays should be drawn with a dark color. Intended for
  /// applications with a light background.
  static const SystemUiOverlayStyle dark = SystemUiOverlayStyle(
    systemNavigationBarColor: Color(0xFF000000),
    systemNavigationBarDividerColor: null,
    statusBarColor: null,
    systemNavigationBarIconBrightness: Brightness.light,
    statusBarIconBrightness: Brightness.dark,
    statusBarBrightness: Brightness.light,
  );

使用

白色

void main() {
  runApp(MyApp());
  //白色
  SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle.light);
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      home: Scaffold(
        backgroundColor: Colors.blue,
        body: Container(),
      ),
    );
  }
}

image.png

黑色

void main() {
  runApp(MyApp());
  //黑色
  SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle.dark);
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      home: Scaffold(
        backgroundColor: Colors.white,
        body: Container(),
      ),
    );
  }
}

黑色