Flutter入门-创新互联

Dart语言中文网 http://dart.goodev.org/

Flutter官网 https://flutter.dev/

Flutter中文网  https://flutterchina.club/

一、windows环境搭建

• 配置镜像（加快FlutterSDK下载）       

官方写的这个export是用在linux上的

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

window上要将export换成set，但是去环境变量界面查看竟然没有

cmd 输入set，会查看所有的环境变量，发现有设置的环境变量。

• 下载FlutterSDK

  下载FlutterSDK,在path里配置“flutter\bin”的环境变量。

  执行flutter doctor，下载FlutterSDK相关的依赖。

• Android Studio上安装Flutter和Dart插件

二、创建Flutter项目

• 创建项目

这里的flutter sdk path就是flutter文件夹位置

*****和创建Android APP项目对比可发现，没有了minSdk、targetSdk这些个选项。（意思）

• 运行项目

首次运行，可能会有以下错误：

Launching lib\main.dart on SM N9009 in debug mode...
Initializing gradle...
Finished with error: ProcessException: Process "F:\Work\Flutter\flutter_app\android\gradlew.bat" exited abnormally:
Downloading https://services.gradle.org/distributions/gradle-4.10.2-all.zip
..................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

Exception in thread "main" javax.net.ssl.SSLException: Connection has been shutdown: javax.net.ssl.SSLException: java.net.SocketException: Connection reset
	at sun.security.ssl.SSLSocketImpl.checkEOF(SSLSocketImpl.java:1551)
	at sun.security.ssl.AppInputStream.available(AppInputStream.java:60)
	at java.io.BufferedInputStream.available(BufferedInputStream.java:410)
	at sun.net.www.MeteredStream.available(MeteredStream.java:170)
	at sun.net.www.http.KeepAliveStream.close(KeepAliveStream.java:85)
	at java.io.FilterInputStream.close(FilterInputStream.java:181)
	at sun.net.www.protocol.http.HttpURLConnection$HttpInputStream.close(HttpURLConnection.java:3448)
	at org.gradle.wrapper.Download.downloadInternal(Download.java:77)
	at org.gradle.wrapper.Download.download(Download.java:44)
	at org.gradle.wrapper.Install$1.call(Install.java:61)
	at org.gradle.wrapper.Install$1.call(Install.java:48)
	at org.gradle.wrapper.ExclusiveFileAccessManager.access(ExclusiveFileAccessManager.java:65)
	at org.gradle.wrapper.Install.createDist(Install.java:48)
	at org.gradle.wrapper.WrapperExecutor.execute(WrapperExecutor.java:128)
	at org.gradle.wrapper.GradleWrapperMain.main(GradleWrapperMain.java:61)
Caused by: javax.net.ssl.SSLException: java.net.SocketException: Connection reset
	at sun.security.ssl.Alerts.getSSLException(Alerts.java:208)
	at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1959)
	at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1916)
	at sun.security.ssl.SSLSocketImpl.handleException(SSLSocketImpl.java:1880)
	at sun.security.ssl.SSLSocketImpl.handleException(SSLSocketImpl.java:1825)
	at sun.security.ssl.AppInputStream.read(AppInputStream.java:116)
	at java.io.BufferedInputStream.read1(BufferedInputStream.java:284)
	at java.io.BufferedInputStream.read(BufferedInputStream.java:345)
	at sun.net.www.MeteredStream.read(MeteredStream.java:134)
	at java.io.FilterInputStream.read(FilterInputStream.java:133)
	at sun.net.www.protocol.http.HttpURLConnection$HttpInputStream.read(HttpURLConnection.java:3375)
	at sun.net.www.protocol.http.HttpURLConnection$HttpInputStream.read(HttpURLConnection.java:3368)
	at org.gradle.wrapper.Download.downloadInternal(Download.java:62)
	... 7 more
Caused by: java.net.SocketException: Connection reset
	at java.net.SocketInputStream.read(SocketInputStream.java:210)
	at java.net.SocketInputStream.read(SocketInputStream.java:141)
	at sun.security.ssl.InputRecord.readFully(InputRecord.java:465)
	at sun.security.ssl.InputRecord.readV3Record(InputRecord.java:593)
	at sun.security.ssl.InputRecord.read(InputRecord.java:532)
	at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:983)
	at sun.security.ssl.SSLSocketImpl.readDataRecord(SSLSocketImpl.java:940)
	at sun.security.ssl.AppInputStream.read(AppInputStream.java:105)
	... 14 more
  Command: F:\Work\Flutter\flutter_app\android\gradlew.bat -v

这个是在下载gradle，网络不好的原因。如果网络好了，run会自动下载gradle，run成功之后，控制台会显示：

    Launching lib\main.dart on SM N9009 in debug mode...
Initializing gradle...
Resolving dependencies...
[{"event":"app.progress","params":{"appId":"d62136c6-30c8-4426-8e6e-e1ec5bdf918e","id":"2","progressId":null,"message":"Running Gradle task 'assembleDebug'..."}}]Running Gradle task 'assembleDebug'...

Built build\app\outputs\apk\debug\app-debug.apk.
Installing build\app\outputs\apk\app.apk...
[{"event":"app.progress","params":{"appId":"d62136c6-30c8-4426-8e6e-e1ec5bdf918e","id":"4","progressId":null,"message":"Syncing files to device SM N9009..."}}]Syncing files to device SM N9009...

赶紧体验了一把“热重载”特性，实在是非常爽！！！

 另外，通过控制台日志可以发现：

Launching lib\main.dart on SM N9009 in debug mode...
Initializing gradle...
Resolving dependencies...
Running Gradle task 'assembleDebug'...
Built build\app\outputs\apk\debug\app-debug.apk.
Installing build\app\outputs\apk\app.apk...
Syncing files to device SM N9009...

项目第一次run的时候，也会生成apk文件。

• 打开项目出现一直提示加载的问题    

   Android Studio使用flutter upgrade等时提示waiting for another flutter command to release the startup lock

解决办法：

    先打开任务管理器，结束掉所有dart.exe。然后打开你的flutter安装文件夹，找到\bin\cache中的lockfile文件删除。之后重启Android Studio。

• 依赖package

****更新yaml文件之后，点击Packages get，即可将包下载下来。

然后在dart里import

**** yaml文件，点击Get dependencies，会报下面的错误，不用管就行。

Working dir: F:\Work\Flutter\startup_namer
G:\Android\flutter_windows_v1.7.8+hotfix.4-stable\flutter\bin\cache\dart-sdk\bin\pub.bat upgrade
Resolving dependencies...
Because startup_namer depends on flutter_test any from sdk which doesn't exist (the Flutter SDK is not available), version solving failed.

Flutter users should run `flutter pub get` instead of `pub get`.
Process finished with exit code 69

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