前面的安裝這裏就不敘述了。看這裏：技術胖的Flutter（http://jspang.com/post/flutte...）
按照步驟安裝後，還是一直報錯，到絕望。。。
錯誤代碼如下：
Error running Gradle:
ProcessException: Process "D:\project\Flutter\flutter_app\android\gradlew.bat" exited abnormally:
> Configure project :app
Checking the license for package Android SDK Platform 27 in C:\Users\Administrator.WINMICR-H4QQDHF\AppData\Local\Android\Sdk\licenses
Warning: License for package Android SDK Platform 27 not accepted.
FAILURE: Build failed with an exception.
* Where:
Build file 'D:\project\Flutter\flutter_app\android\build.gradle' line: 26
* What went wrong:
A problem occurred evaluating root project 'android'.
> A problem occurred configuring project ':app'.
> Failed to install the following Android SDK packages as some licences have not been accepted.
platforms;android-27 Android SDK Platform 27
To build this project, accept the SDK license agreements and install the missing components using the Android Studio SDK Manager.
Alternatively, to transfer the license agreements from one workstation to another, see http://d.android.com/r/studio-ui/export-licenses.html
Using Android SDK: C:\Users\Administrator.WINMICR-H4QQDHF\AppData\Local\Android\Sdk
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
* Get more help at https://help.gradle.org
BUILD FAILED in 1s
Command: D:\project\Flutter\flutter_app\android\gradlew.bat app:properties
Finished with error: Please review your Gradle project setup in the android/ folder.
解決辦法：
把項目的android/app目錄下的build.gradle文件中的sdk版本號改掉，原本是27，改成28.
路徑：
代碼如下：
