Flutter开发常见问题，解决小技巧

1.Android Studio 4.0 以上打包编译报错；

Execution failed for task ':app:lintVitalRelease'.
> Could not resolve all artifacts for configuration ':app:debugRuntimeClasspath'.> Failed to transform libs.jar to match attributes {artifactType=processed-jar, org.gradle.libraryelements=jar, org.gradle.usage=java-runtime}.> Execution failed for JetifyTransform: E:\FlutterSpace\xxxx\build\app\intermediates\flutter\debug\libs.jar.> Transform's input file does not exist: E:\FlutterSpace\xxxx\build\app\intermediates\flutter\debug\libs.jar. (See https://issuetracker.google.com/
issues/158753935)* 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

1.在子build.gradle添加以下代码：

android{lintOptions { checkReleaseBuilds false }
}

解决方案：原文地址：https://my.oschina.net/u/4364921/blog/4725237

2.Exception: Gradle build failed to produce an .apk file. It’s likely that this file was generated under /build, but the tool couldn’t find it.

打包时找不到渠道包名导致；

1.通过VSCode找到项目当中有一 launch.json 文件

{// Use IntelliSense to learn about possible attributes.// Hover to view descriptions of existing attributes.// For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387"version": "0.2.0","configurations": [{"name": "YOUR_PROJECT_NAME",//你项目的名称"program": "lib/main.dart","request": "launch","type": "dart","args": ["--flavor","ADD_YOUR_FLAVOR_NAME_HERE" //配置你的渠道包名]}]

2.通过Andorid Studio 找到子build.gradle文件添加渠道配置;

android {compileOptions {targetCompatibility JavaVersion.VERSION_1_8sourceCompatibility JavaVersion.VERSION_1_8}android.applicationVariants.all {variant ->variant.outputs.all {//在这里修改apk文件名outputFileName = "-v${variant.versionName}-${variant.productFlavors[0].name}-release.apk"}}productFlavors {pgyer {}   // 蒲公英huawei {}       // 华为商店baidu {}        // 百度手机助手yinyongbao {}   // 应用宝xiaomi {}   // 小米oppo {}   // OPPOvivo {}   // VIVOs360 {}   // 360lenovo {}   // 联想aliuc {}   // 阿里UC}// 批量渠道包值替换（有些第三方库中需要用到渠道名）productFlavors.all { flavor ->// 友盟推送渠道包， UMENG_CHANNEL_VALUE 是根据你AndroidManifest.xml来配置的，请看下面。flavor.manifestPlaceholders = [UMENG_CHANNEL_VALUE: name]}//解决打包异常的问题lintOptions { checkReleaseBuilds false }
}

解决方案：https://stackoverflow.com/questions/59732883/flutter-gradle-build-failed-to-produce-an-apk-file-its-likely-that-this-file

3._positions.isNotEmpty, ‘ScrollController not attached to any scroll views.’

具体报错问题；

The following assertion was thrown building Swiper(state: _SwiperState#e86c5):
ScrollController not attached to any scroll views.
'package:flutter/src/widgets/scroll_controller.dart':
Failed assertion: line 108 pos 12: '_positions.isNotEmpty'

解决方案：https://blog.csdn.net/youtiankeng/article/details/107419322

4.Android studio Flutter 开发快捷键

https://flutter.cn/docs/development/tools/android-studio

5.Flutter WebView js交互

html 测试代码块

<html>
<head><title>Js调用Flutter</title><script>function Close() {AppWndClose.postMessage("JS调用了Flutter");}</script>
</head><body>
<br>
<input type="button" value="关闭" onclick="Close()"/>
</body>
</html>

flutter 测试代码块

WebView(javascriptChannels: <JavascriptChannel>[ JavascriptChannel(name: 'AppWndClose',onMessageReceived: (JavascriptMessage message) {showToast(message.message);})].toSet(),
)

我们要注意的是代码里面使用的都是AppWndClose ；这个是我们要注意到的；
参考地址：https://zhuanlan.zhihu.com/p/124797055

6.Flutter WebView跳转dart界面

通过js的方法进行调用；

class CustomWebViewPage extends StatefulWidget {final String url;CustomWebViewPage({Key key,@required this.url,});@overridecreateState() => _PageState();
}class _PageState extends State<CustomWebViewPage> with WidgetsBindingObserver {_PageState();FlutterWebviewPlugin _webViewPlugin = FlutterWebviewPlugin();double lineProgress = 0.0;bool loadError = false;HomeModel homeModel;initState() {super.initState();_webViewPlugin.onProgressChanged.listen((progress) {print(progress);setState(() {lineProgress = progress;});});_webViewPlugin.onHttpError.listen((progress) {setState(() {loadError = true;});});_webViewPlugin.onStateChanged.listen((event) {if (event.type == WebViewState.finishLoad) {}setState(() {});});WidgetsBinding.instance.addObserver(this);EventBus.getDefault().register(this, (data) {if (data is PublishPostsEvent || data == 'tabRankList') {_webViewPlugin.evalJavascript("RefreshMissionList()").then((res) {print("evaluateJavascript-res: ${res}");});}});_wlakPermission(false);}@overridevoid didChangeAppLifecycleState(AppLifecycleState state) {print("-didChangeAppLifecycleState-" + state.toString());switch (state) {case AppLifecycleState.inactive: // 处于这种状态的应用程序应该假设它们可能在任何时候暂停。break;case AppLifecycleState.resumed: //从后台切换前台，界面可见_webViewPlugin.evalJavascript("AppOnShow()").then((res) {print("evaluateJavascript-res: ${res}");});break;case AppLifecycleState.paused: // 界面不可见，后台_webViewPlugin.evalJavascript("AppOnHide()").then((res) {print("evaluateJavascript-res: ${res}");});;break;case AppLifecycleState.detached: // APP结束时调用break;}}@overrideWidget build(BuildContext context) {homeModel = Provider.of<HomeModel>(context);return WebviewScaffold(url: widget.url,mediaPlaybackRequiresUserGesture: false,withZoom: false,withJavascript: true,clearCookies: true,hidden: true,javascriptChannels: <JavascriptChannel>[JavascriptChannel(name: "AppWndClose",onMessageReceived: (JavascriptMessage message) {NavigatorUtils.goBack(context);}),_postThread(),_partInTopic(),].toSet(),initialChild: Container(child: Stack(children: [Center(child: StateLayout(type: loadError ? StateType.network : StateType.loading,)),_setTitle(context),],),));}_postThread() {return JavascriptChannel(name: "eventPostThread",onMessageReceived: (JavascriptMessage message) {_webViewPlugin.hide();print("参数： ${message.message}");NavigatorUtils.push(context, ProfileRouter.publishPosts).then((value) {_webViewPlugin.show();_webViewPlugin.evalJavascript("RefreshMissionList()").then((res) {print("evaluateJavascript-res: ${res}");});});});}_partInTopic() {return JavascriptChannel(name: "eventTaskPartinTopic",onMessageReceived: (JavascriptMessage message) {// 因为flutter_webview_plugin 是浮在flutterUI上的一层视图，它不在widget树中，跳转到dart页面时，需要隐藏掉web页面_webViewPlugin.hide();NavigatorUtils.push(context, TopicRouter.topic).then((value) {//再跳回来时再显示web页面_webViewPlugin.show();_webViewPlugin.evalJavascript("RefreshMissionList()").then((res) {//同时调用web端接口进行刷新操作；});});});}_setTitle(context) {return Positioned(left: 15,top: MediaQuery.of(context).padding.top + 5,child: BackButton(onPressed: () {NavigatorUtils.goBack(context);},),);}_progressBar(double progress, BuildContext context) {return Offstage(offstage: progress == 1.0,child: Container(child: LinearProgressIndicator(backgroundColor: Colors.blueAccent.withOpacity(0),value: progress == 1.0 ? 0 : progress,valueColor: new AlwaysStoppedAnimation<Color>(Colors.lightBlue),),height: 2,));}@overridevoid dispose() {_webViewPlugin.dispose();WidgetsBinding.instance.removeObserver(this);EventBus.getDefault().unregister(this);super.dispose();}
}

通过加载URL的形式进行监听响应跳转；


///省略上面代码；@overridevoid initState() {super.initState();flutterWebviewPlugin.onUrlChanged.listen((loadUrl){//WebviewScaffold 加载的url变化时触发此方法// print('===>>当前 url:$loadUrl');// h5 点退出按钮，关闭webViewif (loadUrl.endsWith('/backapp')){flutterWebviewPlugin.close();pop();}// 跳转到dart页面else if (loadUrl.endsWith('/policy')){// 因为flutter_webview_plugin 是浮在flutterUI上的一层视图，它不在widget树中，跳转到dart页面时，需要隐藏掉web页面，再跳回来时再显示web页面flutterWebviewPlugin.hide(); routePush(ClassRoomPage()).then((value) {flutterWebviewPlugin.show();flutterWebviewPlugin.reloadUrl(widget.url);});//跳转到dart页面时，也可以关闭掉web页面，再跳回来时再创建一个web页面// flutterWebviewPlugin.close();// routePush(ClassRoomPage()).then((value){//   flutterWebviewPlugin.launch(widget.url,//     rect: new Rect.fromLTWH( // 设置web页面的尺寸//       0.0,//       _navBarHeight,//       MediaQuery.of(_context).size.width,//       MediaQuery.of(_context).size.height-_navBarHeight,//     ),//   );// });}});//加载错误时监听// flutterWebviewPlugin.onHttpError.listen((error){//   print('加载错误:${error.code}  ${error.url}');// });//加载状态变化监听// flutterWebviewPlugin.onStateChanged.listen((state){//   print('状态监听:${state.type.toString()}');// });}

参考文章：flutter_webview_plugin 与dart页面跳转使用

7. cmdline-tools component is missing Run `path/to/sdkmanager --install "cmdline-tools;latest"`

参考文章：https://blog.csdn.net/weixin_41824429/article/details/118942087

8.android studio安装和flutter project创建卡住问题解决

参考文章：https://blog.csdn.net/lucynie/article/details/106928231

9. Android licenses not accepted. To resolve this, run: flutter doctor --android-licenses

参考文章：https://www.jianshu.com/p/4feeec038482

10.Flutter Getx 结合 TabView

参考文章：https://stackoverflow.com/questions/63924491/how-to-build-a-tabview-using-flutter-getx

11. Flutter 项目window应用鼠标无法滚动


const Set<PointerDeviceKind> _kTouchLikeDeviceTypes = <PointerDeviceKind>{PointerDeviceKind.touch,PointerDeviceKind.mouse,PointerDeviceKind.stylus,PointerDeviceKind.invertedStylus,PointerDeviceKind.unknown
};MaterialApp(...scrollBehavior: const MaterialScrollBehavior().copyWith(scrollbars: true,dragDevices: _kTouchLikeDeviceTypes),...
);//如果你使用的是Getx框架同上，有相同的属性；scrollBehavior

参考文章：https://www.cnblogs.com/yangyxd/p/15080537.html

12. Flutter 项目window应用运行异常

问题：

CMake Error at CMakeLists.txt:2 (project):GeneratorVisual Studio 16 2019could not find any instance of Visual Studio.

具体解决方法：

https://stackoverflow.com/questions/69944913/cmake-error-while-running-flutter-desktop-application/69951396#69951396 。 Flutter 2.9 版支持 VS 2022，而您使用的 2.8.1 版仅支持 VS 2019。只需安装 2019 并试一试。
如果你想在 2.8.1 版本中使用 VS 2022，这里是解决方法。 stackoverflow.com/a/69951396/6566310 我想这个解决方法是值得的。
感谢您提供这两种解决方案。但我确实选择了第一个，现在它正在工作。

解决方案：https://www.likecs.com/ask-5954170.html

12. Flutter创建本地 Library 工具类

解决方案：https://www.jianshu.com/p/70f874765965