以下是你需要知道的一切:

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() {
  SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle(
    systemNavigationBarColor: Colors.amber, // navigation bar color
    statusBarColor: Colors.white, // status bar color
    statusBarIconBrightness: Brightness.dark, // status bar icon color
    systemNavigationBarIconBrightness: Brightness.dark, // color of navigation controls
  ));
  runApp(MyApp());
}

在Flutter 2.8:

AppBar(
    backgroundColor: YOUR_COLOR_HERE,
    toolbarHeight: 0,
);

你也可以在SliverAppBar中使用这个，不要忘记使用backwardsCompatibility: false如果你跳过这个属性，它将不起作用。参见doc

@override
  Widget build(BuildContext context) {    
    return Scaffold(
      appBar: null,
      body: CustomScrollView(
        slivers: <Widget>[
          SliverAppBar(
              systemOverlayStyle: SystemUiOverlayStyle(
                  statusBarColor: Colors.transparent,
                  statusBarIconBrightness: Brightness.dark),
              backwardsCompatibility: false,
//... remaining code and close braces..

完整的示例

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      debugShowCheckedModeBanner: false,
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return AnnotatedRegion<SystemUiOverlayStyle>(
      value: const SystemUiOverlayStyle(
        systemNavigationBarColor: Colors.red, // navigation bar color
        systemNavigationBarIconBrightness: Brightness.light, //navigation bar icons' color
      ),
      child: Scaffold(
        appBar: AppBar(
          backgroundColor: Colors.red,
          title: const Text('data'),
          systemOverlayStyle: SystemUiOverlayStyle.dark.copyWith(
            statusBarColor: Colors.red,
            statusBarIconBrightness: Brightness.light,
          ),
        ),
      ),
    );
  }
}

更新Flutter 2.0(推荐):

在最新的Flutter版本上，您应该使用:

AppBar(
  systemOverlayStyle: SystemUiOverlayStyle(
    // Status bar color
    statusBarColor: Colors.red, 

    // Status bar brightness (optional)
    statusBarIconBrightness: Brightness.dark, // For Android (dark icons)
    statusBarBrightness: Brightness.light, // For iOS (dark icons)
  ),
)

只有Android(更灵活):

import 'package:flutter/services.dart';

void main() {
  SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle(
    systemNavigationBarColor: Colors.blue, // navigation bar color
    statusBarColor: Colors.pink, // status bar color
  ));
}

iOS和Android:

appBar: AppBar(
  backgroundColor: Colors.red, // Status bar color
)

这有点老套，但适用于iOS和Android:

Container(
  color: Colors.red, // Status bar color
  child: SafeArea(
    left: false,
    right: false,
    bottom: false,
    child: Scaffold(
      appBar: AppBar(
        backgroundColor: Colors.blue, // App bar color
      ),
    ),
  ),
) 

你可以在Android上使用:

 import 'package:flutter/services.dart';

void main() {
  SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle(
    systemNavigationBarColor: Colors.blue, // navigation bar color
    statusBarColor: Colors.pink, // status bar color
  ));
}