if (Platform.isAndroid) {
  // Android-specific code/UI Component
} else if (Platform.isIOS) {
  // iOS-specific code/UI Component
}

不要忘记导入IO库。

import 'dart:io';

如果你使用导入'dart:html';那么你必须指定平台定义，因为两个库都有“平台”的定义

在这种情况下，使用如下所示的平台特定代码:

import 'dart:io' as IO;
import 'dart:html';

if (IO.Platform.isAndroid) {
  // Android-specific code/UI Component
} else if (IO.Platform.isIOS) {
  // iOS-specific code/UI Component
}

如果你正在寻找合适的平台集成，我建议在Flutter网站上使用完整的示例: https://flutter.dev/docs/development/platform-integration/platform-channels

导入io库很简单

import'dart:io' show Platform;
void main(){
if(Platform.isIOS){
  return someThing();
}else if(Platform.isAndroid){
  return otherThing();
}else if(Platform.isMacOS){
  return anotherThing();
}

或者用非常简单的方式

Platform.isIOS ? someThing() : anOther(),

import 'dart:io' show Platform;

if (Platform.isAndroid) {
  // Android-specific code
} else if (Platform.isIOS) {
  // iOS-specific code
}else if (Platform.isFuchsia) {
  // Fuchsia-specific code
}else if (Platform.isLinux) {
  // Linux-specific code
}else if (Platform.isMacOS) {
  // MacOS-specific code
}else if (Platform.isWindows) {
  // Windows-specific code
}else if (Platform.isWindows) {
  // Windows-specific code
}

网络

import 'package:flutter/foundation.dart' show kIsWeb;

if (kIsWeb) {
  // running on the web!
} else {
  // NOT running on the web! You can check for additional platforms here.
}

如果你同时导入"dart:io"和"dart:html"，它不知道要导入哪个平台并给出错误。导入其中一个。

import 'dart:io';
Platform.isIOS ? CupertinoWidget() : MaterialWidget()

您可以将此扩展添加到项目中

import 'package:flutter/material.dart';

extension PlatformExtension on BuildContext {
  bool get isMobile =>
      Theme.of(this).platform == TargetPlatform.iOS ||
      Theme.of(this).platform == TargetPlatform.android;

  bool get isDesktop =>
      Theme.of(this).platform == TargetPlatform.macOS ||
      Theme.of(this).platform == TargetPlatform.windows ||
      Theme.of(this).platform == TargetPlatform.linux;
}

extension TargetPlatformExtension on TargetPlatform {
  bool get isMobile =>
      this == TargetPlatform.iOS || this == TargetPlatform.android;

  bool get isDesktop =>
      this == TargetPlatform.linux ||
      this == TargetPlatform.macOS ||
      this == TargetPlatform.windows;
}

现在您可以使用。

内置context => context.isDesktop 目标平台=> defaulttarded平台

建议从上下文访问平台。

要检测您的应用程序是否在浏览器上运行，您可以轻松地使用基础库中的kIsWeb常量。

import 'package:flutter/foundation.dart';

  log('$kIsWeb'); // will print true if the app is running on a browser

注意，如果你在桌面上运行web应用程序，isDesktop getter将返回true，对于移动平台也是如此。 为了避免这种情况。

import 'package:flutter/foundation.dart';

  if (!kIsWeb && defaultTargetPlatform.isDesktop) {
    // do stuff for desktop apps only
  }

  if (!kIsWeb && defaultTargetPlatform.isMobile) {
    // do stuff for mobile apps only
  }

您可以修改扩展以获得您喜欢的实现。

这个自定义创建的类将帮助您检测平台:

import 'package:flutter/foundation.dart'
    show defaultTargetPlatform, kIsWeb, TargetPlatform;

enum Os {
  web,
  android,
  ios,
  macOS,
  linux,
  windows,
  fuchsia,
}

class Platform {
  const Platform();

  /// Platform is Web.
  static bool get isWeb => os == Os.web;

  /// Platform is Android.
  static bool get isAndroid => os == Os.android;

  /// Platform is IOS.
  static bool get isIOS => os == Os.ios;

  /// Platform is Fuchsia.
  static bool get isFuchsia => os == Os.fuchsia;

  /// Platform is Linux.
  static bool get isLinux => os == Os.linux;

  /// Platform is MacOS.
  static bool get isMacOS => os == Os.macOS;

  /// Platform is Windows.
  static bool get isWindows => os == Os.windows;

  /// Platform is Android or IOS.
  static bool get isMobile => isAndroid || isIOS;

  /// Platform is Android or IOS or Fuchsia.
  static bool get isFullMobile => isMobile || isFuchsia;

  /// Platform is Linux or Windows or MacOS.
  static bool get isDesktop => isLinux || isWindows || isMacOS;

  /// Getting the os name.
  static Os get os {
    if (kIsWeb) {
      return Os.web;
    }
    switch (defaultTargetPlatform) {
      case TargetPlatform.android:
        return Os.android;
      case TargetPlatform.iOS:
        return Os.ios;
      case TargetPlatform.macOS:
        return Os.macOS;
      case TargetPlatform.windows:
        return Os.windows;
      case TargetPlatform.fuchsia:
        return Os.fuchsia;
      case TargetPlatform.linux:
        return Os.linux;
    }
  }
}