Flutter环境搭建及新建项目-编程知识

一、下载安装压缩包

https://storage.flutter-io.cn/flutter_infra_release/releases/stable/windows/flutter_windows_3.10.6-stable.zip

二、解压缩

解压之后，将里面的flutter整体拿出来

三、配置环境变量

将flutter/bin全路径配置到系统环境变量里面

四、运行flutter doctor

打开cmd命令窗口，运行flutter doctor 命令

这个命令运行比较慢，需要耐心等一会儿，注意观察一些错误信息：

五、解决flutter doctor检测出来的问题

1，X cmdline-tools component is missing

X cmdline-tools component is missing

Run path/to/sdkmanager --install "cmdline-tools;latest"

See https://developer.android.com/studio/command-line for more details.

解决

打开Android Studio，进入SDK Manager，在SDK Tools栏，下载Android SDK Command-line Tools (latest)

解决完成！重新 flutter doctor，得到提示信息如下：

2，X Android license status unknown.

X Android license status unknown.

Run ' flutter doctor --android-licenses ' to accept the SDK licenses.

See Windows install | Flutter for more details.

根据错误提示，可以看到，运行flutter doctor --android-licenses命令，接受SDK许可

那就重新打开cmd命令床靠，运行flutter doctor --android-licenses命令

运行flutter doctor --android-licenses命令又报错了

好吧，先解决这个错误，然后再去运行flutter doctor --android-licenses命令，

3，UnsupportedClassVersionError

Error: A JNI error has occurred, please check your installation and try again

Exception in thread "main" java.lang.UnsupportedClassVersionError: com/android/sdklib/tool/sdkmanager/SdkManagerCli has been compiled by a more recent version of the Java Runtime (class file version 61.0), this version of the Java Runtime only recognizes class file versions up to 52.0

at java.lang.ClassLoader.defineClass1(Native Method)

at java.lang.ClassLoader.defineClass(ClassLoader.java:756)

at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)

at java.net.URLClassLoader.defineClass(URLClassLoader.java:473)

at java.net.URLClassLoader.access$100(URLClassLoader.java:74)

at java.net.URLClassLoader$1.run(URLClassLoader.java:369)

at java.net.URLClassLoader$1.run(URLClassLoader.java:363)

at java.security.AccessController.doPrivileged(Native Method)

at java.net.URLClassLoader.findClass(URLClassLoader.java:362)

at java.lang.ClassLoader.loadClass(ClassLoader.java:418)

at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:355)

at java.lang.ClassLoader.loadClass(ClassLoader.java:351)

at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:601)

解决方案：检查本地安装的JDK版本是不是java8，我的就是java8，然后查看一下Android Studio的SDK Manager中的Android sDK Command-line Tools (latest)，版本是多少，我的版本是11，与Java的版本8不匹配，这里要匹配上，所以我要重新下载Android sDK Command-line Tools (latest)版本号为8 的，删掉现有的版本号为11的

下载完之后，重新运行flutter doctor --android-licenses命令，不在报错

4，继续执行flutter doctor --android-licenses命令

上面说到，继续运行flutter doctor --android-licenses命令不再报错，但是会一直提示：

XXXXXX(y/N)?：

只需要一路都敲“y”，同意接受就行，这样就完成了SDK许可接受。

5，X Visual Studio not installed

完成了上面的授权许可操作，我们再次运行flutter doctor命令，此时看到的提示信息如下，一目了然，需要我们下载安装 Visual Studio，我们按照提示，下载安装Visual Studio就行

[X] Visual Studio - develop for Windows

X Visual Studio not installed; this is necessary for Windows development.

Download at Download Visual Studio Tools - Install Free for Windows, Mac, Linux

Please install the "Desktop development with C++" workload, including all of its default components

下载安装的时候需要注意，勾选C++桌面开发，否则再次flutter doctor还是会提示Visual Studio有问题。

6，Connected device (the doctor check crashed)

[☠] Connected device (the doctor check crashed)

X Due to an error, the doctor check did not complete. If the error message below is not helpful, please let us know

about this issue at https://github.com/flutter/flutter/issues.

X Exception: Unable to run "adb", check your Android SDK installation and ANDROID_SDK_ROOT environment variable:

D:\Development\Android\Sdk\platform-tools\adb.exe

安装完Visual Studio之后，再次cmd运行flutter doctor，报错信息如上，具体的截图如下：

解决：这个问题是因为连接不到我本地安装的Android Studio的虚拟机，无法启动adb.exe，百度半天没找到原因，后来发现，我电脑上的零信任环境下面正在运行Android Studio。零信任是我电脑单独分配空间安装了一个公司的虚拟机环境，做到代码物理隔绝。将零信任中的Android Studio关掉即可，上面错误就不存在了。实际上就是零信任环境运行AS占用了我们的adb资源，导致外面环境启动不了adb。

7，Network resources

[!] Network resources

X A network error occurred while checking "Dart packages": 信号灯超时时间已到

X A network error occurred while checking "https://maven.google.com/": 信号灯超时时间已到