这些是我学习Flutter过程中遇到的问题列表

项目问题

Android Studio丢失Image Asset新建项

image-20230525201100880

这样会在新的界面打开IDE，等同步完成，然后就有新建项了。

image-20230525200813317

调试

Flutter编辑时，没有色板预览

需要设置Java运行环境，设置好以后，就可以用了。

image-20230527115127100

Debug条件运行

需要引入flutter/foundation.dart然后，使用kDebugMode进行判断即可。

import 'package:flutter/foundation.dart';
 if (kDebugMode) {
   print(" changed $v");
 }

隐藏Debug 条幅

在代码的theme入口代码添加debugShowCheckedModeBanner: false,,完整代码如下：

class MyApp extends StatelessWidget {
  const MyApp({super.key});
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      debugShowCheckedModeBanner: false,
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

AndroidStudio可以显示设备但是Flutter的设备选择没有设备

先检查Android SDK

PS C:\Windows\system32> flutter doctor --android-licenses
Flutter assets will be downloaded from https://storage.flutter-io.cn. Make sure you trust this source!
Unable to locate Android SDK.

然后设置Android SDK路径

PS C:\Windows\system32> flutter config --android-sdk "D:\Android"
Setting "android-sdk" value to "D:\Android".

You may need to restart any open editors for them to read new settings.

再次验证并查看设备列表

PS C:\Windows\system32> flutter doctor
Flutter assets will be downloaded from https://storage.flutter-io.cn. Make sure you trust this source!
Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel stable, 3.10.2, on Microsoft Windows [版本 10.0.19045.3031], locale zh-CN)
[√] Windows Version (Installed version of Windows is version 10 or higher)
[!] Android toolchain - develop for Android devices (Android SDK version 33.0.2)
    X No Java Development Kit (JDK) found; You must have the environment variable JAVA_HOME set and the java binary in
      your PATH. You can download the JDK from https://www.oracle.com/technetwork/java/javase/downloads/.
[X] Chrome - develop for the web (Cannot find Chrome executable at .\Google\Chrome\Application\chrome.exe)
    ! Cannot find Chrome. Try setting CHROME_EXECUTABLE to a Chrome executable.
[√] Visual Studio - develop for Windows (Visual Studio 生成工具 2022 17.5.5)
[√] Android Studio (version 2022.2)
[!] Android Studio
    X android-studio-dir = D:\Android\Sdk
    X Unable to find bundled Java version.
[√] Connected device (3 available)
[√] Network resources

! Doctor found issues in 3 categories.

查看设备详细列表

PS C:\Windows\system32> flutter devices
Flutter assets will be downloaded from https://storage.flutter-io.cn. Make sure you trust this source!
3 connected devices:

MI 12s (mobile)     • 308710d3 • android-arm64  • Android 13 (API 33)
Windows (desktop) • windows  • windows-x64    • Microsoft Windows [版本 10.0.19045.3031]
Edge (web)        • edge     • web-javascript • Microsoft Edge 92.0.902.67

样式

主题复制修改

在某些情况下，想要继承某个主题，并修改某些属性，可以使用下面的方式：

Widget build(BuildContext context) {
    return  MaterialApp(
      theme: ThemeData.dark().copyWith(
        primaryColor: Colors.orange,
        scaffoldBackgroundColor: Colors.teal
      ),
     .....
}

相关资料

Dart包

文档