我正在尝试运行我正在我的设备上编写的 flutter 应用程序，但是当我尝试运行时，我从未通过“assembleDebug”阶段并在终端中收到此消息：
Launching lib\main.dart on SM N950U in debug mode...
Running Gradle task 'assembleDebug'...
FAILURE: Build failed with an exception.
* What went wrong:
A problem occurred configuring root project 'android'.
> Could not resolve all artifacts for configuration ':classpath'.
> Could not find com.android.tools.build:gradle:5.6.2.
Searched in the following locations:
- https://dl.google.com/dl/android/maven2/com/android/tools/build/gradle/5.6.2/gradle-5.6.2.pom
- https://dl.google.com/dl/android/maven2/com/android/tools/build/gradle/5.6.2/gradle-5.6.2.jar
- https://jcenter.bintray.com/com/android/tools/build/gradle/5.6.2/gradle-5.6.2.pom
- https://jcenter.bintray.com/com/android/tools/build/gradle/5.6.2/gradle-5.6.2.jar
Required by:
project :
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option …