Flutter & Dart 安装在window系统

一、系统环境

flutter最低要求

1，windows7 SP1 64位版本以上，我的系统就是windows 7 sp1 64bit

2，git for windows ，没有安装的需要到这里下载 并安装

3，powershell 5.0及以上，这个据说只有windows10和2016版windows server满足要求

window7 sp1以及自带Powershell，但是版本较低，我的系统中版本居然是2.0

启动：系统左下角-开始-点击搜索框-输入powershell-回车键
在powershell中输入 $PSVersionTable 然后回车，查看其中的PSVersion一行

Windows PowerShell
版权所有 (C)  Microsoft Corporation。保留所有权利。

PS C:\Users\gzg> $PSVersionTable

Name                           Value
----                           -----
CLRVersion                     2.0.50727.8793
BuildVersion                   6.1.7601.17514
PSVersion                      2.0
WSManStackVersion              2.0
PSCompatibleVersions           {1.0, 2.0}
SerializationVersion           1.1.0.1
PSRemotingProtocolVersion      2.1

PS C:\Users\gzg>

如何查看PowerShell版本

由于PS没有单独的发行包，只能下载WMF5.1的发行包

下载后展开，包含如下两个文件，右键点击Install-WMF5.1.ps1，选择用powershell运行安装，过程不赘述。

4，安装配置好android SDK，并建立一个模拟器

5，Android Studio，如果没有请安装http://www.androiddevtools.cn/。

二、下载安装flutter sdk

1，进入预存放flutter目录的父目录中，从github克隆flutter beta版

git clone -b beta https://github.com/flutter/flutter.git

2，设置环境变量

1）将  *\flutter\bin目录加入到环境变量path中

2）添加ANDROID_HOME环境变量，指向android SDK所在目录

3， 设置国内镜像代理，然后执行flutter doctor

打开dos窗口，设置国内镜像

 set PUB_HOSTED_URL=https://pub.flutter-io.cn
 set FLUTTER_STORAGE_BASE_URL=https://storage.flutter-io.cn 

备注：或者也可以直接添加系统变量，以备以后升级安装方便。

4，进行下一步之前，首先关闭杀毒杀木马程序，例如360之类，否则“flutter\bin\cache\artifacts\engine\android-arm64-release\windows-x64\gen_snapshot.exe” 会被认成木马，造成运行失败！

我这里的报错信息如下：

K:\Android\flutter>flutter doctor
Flutter assets will be downloaded from https://storage.flutter-io.cn. Make sure you trust this source!

Oops; flutter has exited unexpectedly.
Sending crash report to Google.

或者，给目录“flutter\bin”添加到信任白名单。如果还有问题，看一看flutter目录下的“flutter_##.log”文件查找原因，然后在解决即可。

5，运行flutter设置命令

flutter doctor

flutter会检测flutter SDK安装情况，然后下载dart SDK和其他依赖项目，由于网络问题运行时间较长，期间不免发生失败情况，需要多运行几次。

PS C:\Users\gzg> flutter doctor
Downloading android-arm-release/windows-x64 tools...
Download failed -- attempting retry 1 in 1 second...
Download failed -- attempting retry 2 in 2 seconds...
Download failed -- attempting retry 3 in 4 seconds...
Download failed -- attempting retry 4 in 8 seconds...
Download failed -- attempting retry 5 in 16 seconds...
Download failed -- attempting retry 6 in 32 seconds...
Download failed -- attempting retry 7 in 64 seconds...
Download failed -- attempting retry 8 in 64 seconds...
365.2s
Downloading android-arm64-profile/windows-x64 tools...           8.2s
Downloading android-arm64-release/windows-x64 tools...           7.6s
Downloading android-x86 tools...
Download failed -- attempting retry 1 in 1 second...
Download failed -- attempting retry 2 in 2 seconds...
142.8s
Downloading android-x64 tools...                                53.4s
Downloading android-arm tools...                                24.4s
Downloading android-arm-profile tools...

Oops; flutter has exited unexpectedly.
Sending crash report to Google.
Failed to send crash report due to a network error: SocketException: OS Error: 信号灯超时时间已到
, errno = 121, address = clients2.google.com, port = 60527
Crash report written to C:\Users\gzg\flutter_03.log;
please let us know at https://github.com/flutter/flutter/issues.
PS C:\Users\gzg> flutter doctor
Downloading android-arm-profile tools...
Download failed -- attempting retry 1 in 1 second...
Download failed -- attempting retry 2 in 2 seconds...
Download failed -- attempting retry 3 in 4 seconds...
Download failed -- attempting retry 4 in 8 seconds...
Download failed -- attempting retry 5 in 16 seconds...
Download failed -- attempting retry 6 in 32 seconds...
254.5s
Downloading android-arm-release tools...
Download failed -- attempting retry 1 in 1 second...
61.0s
Downloading android-arm64 tools...                              27.6s
Downloading android-arm64-profile tools...
Download failed -- attempting retry 1 in 1 second...
71.0s
Downloading android-arm64-release tools...
Download failed -- attempting retry 1 in 1 second...
Download failed -- attempting retry 2 in 2 seconds...
Download failed -- attempting retry 3 in 4 seconds...
Download failed -- attempting retry 4 in 8 seconds...
Download failed -- attempting retry 5 in 16 seconds...

6，最后，flutter doctor命令会给出环境检测结果，如果有些项目有问题，则按照其中说明修正，例如，我这里有两项有问题：

Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel unknown, v0.0.0-unknown, on Microsoft Windows [Version 6.1.7601], locale zh-CN)
[!] Android toolchain - develop for Android devices (Android SDK 28.0.3)
    ! Some Android licenses not accepted.  To resolve this, run: flutter doctor --android-licenses
[√] Android Studio (version 3.2)
[√] IntelliJ IDEA Community Edition (version 2018.2)
[!] Connected device
    ! No devices available

! Doctor found issues in 2 categories.

第二项问题依照蓝色提示操作即可解决。最后一项虚拟机，建立一个虚拟机并启动，再次运行检测，没问题了！

C:\Users\gzg>flutter doctor
Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel unknown, v0.0.0-unknown, on Microsoft Windows [Version 6.1.7601], locale zh-CN)
[√] Android toolchain - develop for Android devices (Android SDK 28.0.3)
[√] Android Studio (version 3.2)
[√] IntelliJ IDEA Community Edition (version 2018.2)
[√] Connected device (1 available)

• No issues found!

三、开始flutter之旅

在android studio中建立flutter项目

菜单“File--New--New Flutter Project...”，第一步选择“Flutter Application”，第二部输入项目名称，注意一定要选中下面的选项“create project offline”，否则在我的网络环境下就进行不下去了。