虽然本次 I/O 的核心 keynote 主要是 AI ，但是按照惯例依然发布了新的 Flutter 稳定版，不过并非大家猜测的 4.0，而是 3.10 ，Flutter 的版本号依然那么的出人意料。
Flutter 3.10 主要包括有对 Web、mobile、graphics、安全性等方面的相关改进，核心其实就是：
Flutter 2.x 升级到 3.10.1 版本之后，原来正常编译的项目，iOS环境下（Xcode Version 13.2.1 (13C100)），编译报错：
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$ ios % pod install Analyzing dependencies [!] Unable to find a target named `RunnerTests` in project `Runner.xcodeproj`, did find `Runner`. [!] Automatically assigning platform `iOS` with version `11.0` on target `Runner` because no platform was specified. Please specify a platform for this target in your Podfile. See `https://guides.cocoapods.org/syntax/podfile.html#platform`. |
继续阅读Unable to find a target named `RunnerTests` in project `Runner.xcodeproj`, did find `Runner`
具体在Xcode中的报错提示如下所示：
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Showing Recent Messages diff: /Users/admin/Documents/WorkSpace/Flutter/portal/ios/Pods/Manifest.lock: No such file or directory error:The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation. |
继续阅读iOS开发：报错The sandbox is not in sync with the Podfile.lock …的解决方法
尝试在 Flutter 上使用 MMKV （1.2.16）的时候，编译报错，如下：
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Launching lib/main.dart on iPod touch (7th generation) in debug mode... Updating minimum iOS deployment target to 11.0. Upgrading Podfile Running pod install... CocoaPods' output: ↳ [!] Invalid `Podfile` file: undefined method `exists?' for File:Class. # from /Users/xxxx/MMKV/flutter/example/ios/Podfile:35 # ------------------------------------------- # plugin_deps_file = File.expand_path(File.join(flutter_application_path, '..', '.flutter-plugins-dependencies')) > if not File.exists?(plugin_deps_file) # is_module = true; # ------------------------------------------- /usr/local/Cellar/cocoapods/1.12.0/libexec/gems/cocoapods-core-1.12.0/lib/cocoapods-core/podfile.rb:335:in `rescue in block in from_ruby' /usr/local/Cellar/cocoapods/1.12.0/libexec/gems/cocoapods-core-1.12.0/lib/cocoapods-core/podfile.rb:329:in `block in from_ruby' /usr/local/Cellar/cocoapods/1.12.0/libexec/gems/cocoapods-core-1.12.0/lib/cocoapods-core/podfile.rb:50:in `instance_eval' /usr/local/Cellar/cocoapods/1.12.0/libexec/gems/cocoapods-core-1.12.0/lib/cocoapods-core/podfile.rb:50:in `initialize' /usr/local/Cellar/cocoapods/1.12.0/libexec/gems/cocoapods-core-1.12.0/lib/cocoapods-core/podfile.rb:327:in `new' /usr/local/Cellar/cocoapods/1.12.0/libexec/gems/cocoapods-core-1.12.0/lib/cocoapods-core/podfile.rb:327:in `from_ruby' /usr/local/Cellar/cocoapods/1.12.0/libexec/gems/cocoapods-core-1.12.0/lib/cocoapods-core/podfile.rb:293:in `from_file' /usr/local/Cellar/cocoapods/1.12.0/libexec/gems/cocoapods-1.12.0/lib/cocoapods/config.rb:205:in `podfile' /usr/local/Cellar/cocoapods/1.12.0/libexec/gems/cocoapods-1.12.0/lib/cocoapods/command.rb:160:in `verify_podfile_exists!' /usr/local/Cellar/cocoapods/1.12.0/libexec/gems/cocoapods-1.12.0/lib/cocoapods/command/install.rb:46:in `run' /usr/local/Cellar/cocoapods/1.12.0/libexec/gems/claide-1.1.0/lib/claide/command.rb:334:in `run' /usr/local/Cellar/cocoapods/1.12.0/libexec/gems/cocoapods-1.12.0/lib/cocoapods/command.rb:52:in `run' /usr/local/Cellar/cocoapods/1.12.0/libexec/gems/cocoapods-1.12.0/bin/pod:55:in `<top (required)>' /usr/local/Cellar/cocoapods/1.12.0/libexec/bin/pod:25:in `load' /usr/local/Cellar/cocoapods/1.12.0/libexec/bin/pod:25:in `<main>' Error running pod install Error launching application on iPod touch (7th generation). |
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$ ruby -v ruby 2.6.10p210 (2022-04-12 revision 67958) [universal.x86_64-darwin20] |
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$ brew install ruby ==> Downloading https://formulae.brew.sh/api/formula.jws.json ######################################################################## 100.0% ==> Downloading https://formulae.brew.sh/api/cask.jws.json ######################################################################## 100.0% Warning: ruby 3.2.1 is already installed and up-to-date. To reinstall 3.2.1, run: brew reinstall ruby $ ruby -v ruby 2.6.10p210 (2022-04-12 revision 67958) [universal.x86_64-darwin20] $ brew link ruby Warning: Refusing to link macOS provided/shadowed software: ruby If you need to have ruby first in your PATH, run: echo 'export PATH="/usr/local/opt/ruby/bin:$PATH"' >> ~/.zshrc For compilers to find ruby you may need to set: export LDFLAGS="-L/usr/local/opt/ruby/lib" export CPPFLAGS="-I/usr/local/opt/ruby/include" For pkg-config to find ruby you may need to set: export PKG_CONFIG_PATH="/usr/local/opt/ruby/lib/pkgconfig" |
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$ flutter doctor Doctor summary (to see all details, run flutter doctor -v): [✓] Flutter (Channel stable, 3.7.7, on macOS 11.7.4 20G1120 darwin-x64, locale zh-Hans-CN) [✓] Android toolchain - develop for Android devices (Android SDK version 33.0.1) [✓] Xcode - develop for iOS and macOS (Xcode 13.2.1) [✓] Chrome - develop for the web [✓] Android Studio (version 2022.1) [✓] IntelliJ IDEA Ultimate Edition (version 2018.3.6) [✓] VS Code (version 1.76.2) [✓] Connected device (3 available) [✓] HTTP Host Availability • No issues found! |
这个问题是由于 cocoapods 升级到 1.12 版本之后，依赖的 ruby 升级到 3.2 版本，其中的 File.exists 函数被替换成 File.exist，导致编译异常。
刚刚开始以为是 Flutter 的原因，结果发现 Flutter 3.7.7版本已经修复这个问题。
尝试了半天，才发现是 MMKV 的问题，主要是 MMKV的 iOS 工程下 flutter/example/ios/Podfile 跟 flutter/example/mmkvpodhelper.rb里面的代码需要进行适配。
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# from ruby 3.2 File.exists is broken, we need compat function def mmkv_file_exists(file) is_exist = false if File.methods.include?(:exists?) is_exist = File.exists? file else is_exist = File.exist? file end return is_exist end |
使用上面的代码替换 File.exists 即可。
Flutter项目是能运行的，打开Flutter里面的Android项目才会报下面错误。
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8:34 Gradle sync started 8:35 Gradle sync failed: Could not create task ':image_picker:generateDebugUnitTestConfig'. this and base files have different roots: D:\Pensoon\flutter_property_check_gd\build\image_picker and C:\Users\XXX\AppData\Roaming\Pub\Cache\hosted\pub.flutter-io.cn\image_picker-0.8.3+2\android. (52 s 230 ms) 8:35 Gradle sync started 8:35 Gradle sync failed: Could not create task ':image_picker:generateDebugUnitTestConfig'. this and base files have different roots: D:\Pensoon\flutter_property_check_gd\build\image_picker and C:\Users\XXX\AppData\Roaming\Pub\Cache\hosted\pub.flutter-io.cn\image_picker-0.8.3+2\android. (2 s 588 ms) |
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$ .\gradlew clean build Configuration on demand is an incubating feature. FAILURE: Build failed with an exception. * What went wrong: Could not determine the dependencies of task ':url_launcher_android:test'. > Could not create task ':url_launcher_android:testDebugUnitTest'. > this and base files have different roots: D:\Source\xxxx\build\url_launcher_android and C:\Users\Administrator\AppData\Local\Pub\Cache\hosted\pub.flutter-io.cn\url_launcher_android-6.0.25\android. |
报错的项目配置信息如下：
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buildscript { ext.kotlin_version = '1.8.0' repositories { maven { url "https://maven.aliyun.com/nexus/content/groups/public/" } maven { url "https://maven.aliyun.com/nexus/content/repositories/google" } google() mavenCentral() } dependencies { classpath 'com.android.tools.build:gradle:7.4.2' classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version" } } allprojects { repositories { maven { url "https://maven.aliyun.com/nexus/content/groups/public" } maven { url "https://maven.aliyun.com/nexus/content/repositories/google" } google() mavenCentral() } } rootProject.buildDir = '../build' subprojects { project.buildDir = "${rootProject.buildDir}/${project.name}" } subprojects { project.evaluationDependsOn(':app') } task clean(type: Delete) { delete rootProject.buildDir } |
Flutter一开始Android build是没问题的，开发着突然就报这个下面的错误，开始怀疑是不是有什么缓存啥的，然后各种排除都没找到什么原因，后面想着降版本吧，kotlin降了没用，后面尝试最后一个Gradle降版本竟然成功了。
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// 报错版本 classpath 'com.android.tools.build:gradle:7.0.0' // 报错版本 classpath 'com.android.tools.build:gradle:7.3.1' // 报错版本 classpath 'com.android.tools.build:gradle:7.4.2' // 解决版本 classpath 'com.android.tools.build:gradle:4.1.3' // 解决版本 classpath 'com.android.tools.build:gradle:4.2.2' |
核心内容原文链接： medium.com/flutter/wha…
2023 年新春之际， Flutter 喜提了 3.7 的大版本更新，在 Flutter 3.7 中主要有改进框架的性能，增加一些很棒的新功能，例如：创建自定义菜单栏、级联菜单、更好地支持国际化的工具、新的调试工具等等。
另外 Flutter 3.7 还改进了 Global selection、使用 Impeller提升渲染能力、DevTools 等功能，以及一如既往的性能优化。
PS ：3.7 版本包含大量，大量，大量更新内容，感觉离 4.0 不远了。
flutter项目，需要使用本地存储，面临三个选择
第二个对桌面版的不支持。
最后选择了hive，用起来还算可以，不过，相对于后台的orm，还是有些东西需要自己处理。
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dependencies: hive: ^[version] hive_flutter: ^[version] dev_dependencies: hive_generator: ^[version] build_runner: ^[version] |
之前做个一阵子后台，按照后台的orm逻辑，组装了一下hive。
main.dart里面初始化hive
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void main() async { await InitHive(); runApp(const MyApp()); } |
hive的初始化部分，初始化了三张表
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import 'package:hive_flutter/adapters.dart'; import 'mclients.dart'; late Box MClients; Future<void> initHive() async { await Hive.initFlutter('data'); Hive.registerAdapter(MClientAdapter()); MClients = await Hive.openBox<MClient>('mclients'); } |
单个表的model
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import 'package:flutter/cupertino.dart'; import 'package:hive_flutter/adapters.dart'; import 'hive.dart'; @HiveType(typeId: 1) class MClient { @HiveField(0) String? clientId; @HiveField(1) String? host; @HiveField(2) String? port; @HiveField(3) String? user; @HiveField(4) String? password; MClient({this.clientId, this.host, this.port, this.user, this.password}); } class MClientAdapter extends TypeAdapter<MClient> { @override final typeId = 0; @override MClient read(BinaryReader reader) { return MClient() ..clientId = reader.read() ..host = reader.read() ..password = reader.read() ..user = reader.read() ..password = reader.read(); } @override void write(BinaryWriter writer, MClient obj) { writer.write(obj.clientId); writer.write(obj.host); writer.write(obj.port); writer.write(obj.user); writer.write(obj.password); } } void clientCreate(clientId, host, port, user, password) { var cc = MClient( clientId: clientId, host: host, port: port, user: user, password: password); MClients.put(clientId, cc); } MClient? clientGet(clientId) { if (MClients.get(clientId) != null) { var cc1 = MClients.get(clientId); return cc1; } else { return null; } } List<MClient> clientGetList() { var res = MClients.values.toList(); List<MClient> cc = res.cast<MClient>(); debugPrint("查到list: $cc"); return cc; } void clientDel(clientId) { MClients.delete(clientId); } |
使用model
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late List<String> clientids; getClientids() { clients = ClientGetList(); clientidsd = List.generate(clients.length, (index) => clients[index].clientid); clientids = clientidsd.cast<String>(); } |
结束。
这篇文章主要讨论的是Fluter中CustomPainter中使用repaint属性实现自动paint的原理。
首先使用CustomPaint创建一个StatefulWidget，demo中根据点击位置，对蓝色的圆进行位置变换。
代码如下
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import 'package:flutter/material.dart'; void main() => runApp(MyPaint()); class MyPaint extends StatefulWidget { const MyPaint({Key? key}) : super(key: key); @override _MyPaintState createState() => _MyPaintState(); } class _MyPaintState extends State<MyPaint> { ValueNotifier<double> _vn = ValueNotifier<double>(0); @override Widget build(BuildContext context) { return GestureDetector( onPanUpdate: parse, child: CustomPaint( painter: BoxPainter(vn: _vn), ), ); } dynamic parse(DragUpdateDetails details) { _vn.value = details.globalPosition.dy; } } class BoxPainter extends CustomPainter { ValueNotifier<double> vn; BoxPainter({@required this.vn}) : super(repaint: vn); @override void paint(Canvas canvas, Size size) { canvas.translate(size.width / 2, 0); canvas.drawCircle(Offset(0, vn.value), 66, Paint()..color = Colors.blue); } @override bool shouldRepaint(BoxPainter oldDelegate) => false; @override bool shouldRebuildSemantics(BoxPainter oldDelegate) => false; } |
flutter 升级到 3.3.9 后，代码编译报错，如下：
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$ flutter run Launching lib/main.dart on iPhone in debug mode... Automatically signing iOS for device deployment using specified development team in Xcode project: 4XS4BW9489 Running Xcode build... └─Compiling, linking and signing... 7.6s Xcode build done. 35.3s (lldb) dyld[627]: Library not loaded: @rpath/libswiftCore.dylib Referenced from: <8B0D72DF-EF41-3748-B8B5-8EF789672FF7> /private/var/containers/Bundle/Application/89C785E1-48B5-4139-8D0B-F392A3865D0B/Runner.app/Runner Reason: tried: '/private/var/containers/Bundle/Application/89C785E1-48B5-4139-8D0B-F392A3865D0B/Runner.app/Frameworks/libswiftCore.dylib' (errno=2), '/private/var/containers/Bundle/Application/89C785E1-48B5-4139-8D0B-F392A3865D0B/Runner.app/Frameworks/libswiftCore.dylib' (errno=2), '/private/preboot/Cryptexes/OS@rpath/libswiftCore.dylib' (errno=2), '/private/var/containers/Bundle/Application/89C785E1-48B5-4139-8D0B-F392A3865D0B/Runner.app/Frameworks/libswiftCore.dylib' (errno=2), '/private/var/containers/Bundle/Application/89C785E1-48B5-4139-8D0B-F392A3865D0B/Runner.app/Frameworks/libswiftCore.dylib' (errno=2), '/usr/local/lib/libswiftCore.dylib' (errno=2), '/usr/lib/libswiftCore.dylib' (errno=2, not in dyld cache) * thread #1, stop reason = signal SIGABRT frame #0: 0x00000001e6efeebc -> 0x1e6efeebc: b.lo 0x1e6efeedc 0x1e6efeec0: pacibsp 0x1e6efeec4: stp x29, x30, [sp, #-0x10]! 0x1e6efeec8: mov x29, sp Target 0: (Runner) stopped. Installing and launching... 26.6s Error launching application on iPhone. |
解决方法就是在工程的 "Build Settings->Linking->Runpath Search Paths" 加上 "/usr/lib/swift" 。
如下图：
继续阅读flutter升级到3.3.9后报错“Library not loaded: @rpath/libswiftCore.dylib”
在今天晚上 ubuntu 22.04 执行如下升级命令之后
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$ sudo apt-get dist-upgrade 正在读取软件包列表... 完成 正在分析软件包的依赖关系树... 完成 正在读取状态信息... 完成 正在计算更新... 完成 下列【新】软件包将被安装： cpp-12 gcc-12 libasan8 libgcc-12-dev libtsan2 下列软件包将被升级： apport apport-gtk dkms firmware-sof-signed libexpat1 libexpat1:i386 libexpat1-dev libflac8 libfreerdp-client2-2 libfreerdp-server2-2 libfreerdp2-2 libwinpr2-2 python3-apport python3-problem-report rsync xserver-common xserver-xephyr xserver-xorg-core xserver-xorg-legacy xwayland 升级了 20 个软件包，新安装了 5 个软件包，要卸载 0 个软件包，有 0 个软件包未被升级。 |
再次执行 flutter 的构建命令，报错。
操作过程如下：
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$ flutter run Launching lib/main.dart on Linux in debug mode... Building Linux application... /usr/include/glib-2.0/glib/glib-typeof.h:39:10: fatal error: 'type_traits' file not found /usr/include/glib-2.0/glib/glib-typeof.h:39:10: fatal error: 'type_traits' file not found Exception: Build process failed $ flutter --version Flutter 3.3.9 • channel stable • https://github.com/flutter/flutter.git Framework • revision b8f7f1f986 (2 天前) • 2022-11-23 06:43:51 +0900 Engine • revision 8f2221fbef Tools • Dart 2.18.5 • DevTools 2.15.0 $ flutter clean $ flutter run Multiple devices found: Linux (desktop) • linux • linux-x64 • Ubuntu 22.04.1 LTS 5.15.0-53-generic Chrome (web) • chrome • web-javascript • Chromium 107.0.5304.110 [1]: Linux (linux) [2]: Chrome (chrome) Please choose one (To quit, press "q/Q"): 1 Running "flutter pub get" in xxxx... 6.2s Launching lib/main.dart on Linux in debug mode... CMake Error at /usr/share/cmake-3.22/Modules/CMakeTestCXXCompiler.cmake:62 (message): The C++ compiler "/usr/bin/clang++" is not able to compile a simple test program. It fails with the following output: Change Dir: /home/xxxx/xxxx/xxxxx/build/linux/x64/debug/CMakeFiles/CMakeTmp Run Build Command(s):/usr/bin/ninja cmTC_8cfda && [1/2] Building CXX object CMakeFiles/cmTC_8cfda.dir/testCXXCompiler.cxx.o [2/2] Linking CXX executable cmTC_8cfda FAILED: cmTC_8cfda : && /usr/bin/clang++ CMakeFiles/cmTC_8cfda.dir/testCXXCompiler.cxx.o -o cmTC_8cfda && : /usr/bin/ld: 找不到 -lstdc++: 没有那个文件或目录 clang: error: linker command failed with exit code 1 (use -v to see invocation) ninja: build stopped: subcommand failed. CMake will not be able to correctly generate this project. Call Stack (most recent call first): CMakeLists.txt:3 (project) Building Linux application... Exception: Unable to generate build files |
解决方法是手工安装依赖：
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$ sudo apt install lib32stdc++-12-dev |
之后再执行构建命令。