Flutter问题汇总

　　　　　Flutter (Channel stable, v1.17.0, on Linux, locale en_US.UTF-8)
　　　　[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.3)
　　　　[✓] Android Studio (version 3.6)
　　　　[✓] Connected device (1 available)

1. 编译时 Your app isn't using AndroidX.

   使用AndroidX导致，解决办法：在项目中android目录中的gradle.properties文件加入以下两行代码
   
   android.enableJetifier=true
   android.useAndroidX=true

2. Compiler message:
   ../../.pub-cache/hosted/pub.flutter-io.cn/cached_network_image-1.1.2/lib/src/cached_network_image_provider.dart:53:24: Error: The method 'CachedNetworkImageProvider.load' has fewer positional arguments than those of overridden method 'ImageProvider.load'.
     ImageStreamCompleter load(CachedNetworkImageProvider key) {
                          ^
   ../../Software/android/sdk/flutter/packages/flutter/lib/src/painting/image_provider.dart:574:24: Context: This is the overridden method ('load').
     ImageStreamCompleter load(T key, DecoderCallback decode);
                          ^
   ../../.pub-cache/hosted/pub.flutter-io.cn/cached_network_image-1.1.2/lib/src/scaled_file_image.dart:45:24: Error: The method 'ScaledFileImage.load' has fewer positional arguments than those of overridden method 'ImageProvider.load'.
     ImageStreamCompleter load(ScaledFileImage key) {
                          ^
   ../../Software/android/sdk/flutter/packages/flutter/lib/src/painting/image_provider.dart:574:24: Context: This is the overridden method ('load').
     ImageStreamCompleter load(T key, DecoderCallback decode);
   解决方案：在pubspec.yaml中修改cached_network_image:1.1.2 为 cached_network_image: 2.0.0-rc

3. FAILURE: Build failed with an exception.
   
   * What went wrong:
   Execution failed for task ':app:compileDebugKotlin'.
   > Could not resolve all artifacts for configuration ':app:debugCompileClasspath'.
      > Could not download arm64_v8a_debug.jar (io.flutter:arm64_v8a_debug:1.0.0-b851c718295a896918dc93cb1ff14f2f895a1b90)
         > Could not get resource 'https://storage.googleapis.com/download.flutter.io/io/flutter/arm64_v8a_debug/1.0.0-b851c718295a896918dc93cb1ff14f2f895a1b90/arm64_v8a_debug-1.0.0-b851c718295a896918dc93cb1ff14f2f895a1b90.jar'.
            > Could not HEAD 'https://storage.googleapis.com/download.flutter.io/io/flutter/arm64_v8a_debug/1.0.0-b851c718295a896918dc93cb1ff14f2f895a1b90/arm64_v8a_debug-1.0.0-b851c718295a896918dc93cb1ff14f2f895a1b90.jar'.
               > Connect to storage.googleapis.com:443 [storage.googleapis.com/34.64.4.112] failed: connect timed out
      > Could not download x86_debug.jar (io.flutter:x86_debug:1.0.0-b851c718295a896918dc93cb1ff14f2f895a1b90)
         > Could not get resource 'https://storage.googleapis.com/download.flutter.io/io/flutter/x86_debug/1.0.0-b851c718295a896918dc93cb1ff14f2f895a1b90/x86_debug-1.0.0-b851c718295a896918dc93cb1ff14f2f895a1b90.jar'.
            > Could not HEAD 'https://storage.googleapis.com/download.flutter.io/io/flutter/x86_debug/1.0.0-b851c718295a896918dc93cb1ff14f2f895a1b90/x86_debug-1.0.0-b851c718295a896918dc93cb1ff14f2f895a1b90.jar'.
               > Connect to storage.googleapis.com:443 [storage.googleapis.com/34.64.4.112] failed: connect timed out
      > Could not download x86_64_debug.jar (io.flutter:x86_64_debug:1.0.0-b851c718295a896918dc93cb1ff14f2f895a1b90)
         > Could not get resource 'https://storage.googleapis.com/download.flutter.io/io/flutter/x86_64_debug/1.0.0-b851c718295a896918dc93cb1ff14f2f895a1b90/x86_64_debug-1.0.0-b851c718295a896918dc93cb1ff14f2f895a1b90.jar'.
            > Could not HEAD 'https://storage.googleapis.com/download.flutter.io/io/flutter/x86_64_debug/1.0.0-b851c718295a896918dc93cb1ff14f2f895a1b90/x86_64_debug-1.0.0-b851c718295a896918dc93cb1ff14f2f895a1b90.jar'.
               > Connect to storage.googleapis.com:443 [storage.googleapis.com/34.64.4.112] failed: connect timed out
   
   * Try:
   Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
   
   * Get more help at https://help.gradle.org
   
   BUILD FAILED in 1m 35s
   Exception: Gradle task assembleDebug failed with exit code 1
   

   解决方案有两种：

   　　第一种：在工程.android目录中，对应的build.gradle文件下，添加代码

   “maven { url "http://download.flutter.io" }”后重新编译，如下

   repositories {
       google()
       jcenter()
       maven { url "http://download.flutter.io" }
   }

   
   第二种：修改flutter sdk中flutter/packages/flutter_tools/gradle/文件夹下三个文件，如下：

   flutter/packages/flutter_tools/gradle/resolve_dependencies.gradle

   flutter/packages/flutter_tools/gradle/aar_init_script.gradle

   flutter/packages/flutter_tools/gradle/flutter.gradle

   中的：https://storage.googleapis.com/download.flutter.io   替换为：http://download.flutter.io 

4. Hot Reload 热重载失效

   在给 Terminal 之类的终端模拟器设置代理之后，会导致“Hot Reload”重载失效，此时调用 Save (cmd-s / ctrl-s)将不会进行热重载，热重载按钮 (带有闪电⚡️图标的按钮)也不会显示，将代理移除即可解决。
   
   另外，有些情况下热重载是不生效的，比如修改了main函数、修改了全局静态方法等，读者可以认为“Hot Reload”只会重新构建整个widget树，如果变动不在构建widget树的过程中，“Hot Reload”就不会起作用。

5. flutter upgrade 报错

   Unable to upgrade Flutter: no origin repository configured. Run 'git remote add origin https://github.com/flutter/flutter' in /home/xx/flutter
   
   解决方案：flutter channel stable