Flutter入门-成都快上网建站

Flutter入门

Dart语言中文网 http://dart.goodev.org/

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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

        Flutter入门

        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

      Flutter入门

        这里的flutter sdk path就是flutter文件夹位置

        Flutter入门

       *****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。

       Flutter入门

        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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