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Flutter项目出现问题：
For those whose Gradle Sync failed, follow these steps:

• Do flutter clean in your project terminal.
• Open android folder of your project using Android Studio -Android Studio->File->Open->Your_Project->Android.
• Now do Gradle Sync.
• Close your android project.
• Do flutter pub get in your flutter project terminal now.

** Android Studio打不开Android项目(Flutter右键),改为使用AS打开新项目的形式打开。