VSCode中Flutter调试模式无法启动应用，Gradle assembleDebug失败

The Exact Scenario (Matching Your Issue) #

I had a fully working Flutter setup where launching apps via AVD or physical Android devices in VS Code debug mode was smooth—until suddenly it broke. The error I got was identical to yours:

Launching lib\main.dart on Android SDK built for x86 in debug mode... Gradle task assembleDebug failed with exit code 1 Exited (sigterm)

I ran through the standard checks first:

• flutter doctor -v showed all environment configurations were completely normal
• flutter run -v threw a "no connected devices" message, even though my AVD/physical device was clearly connected and recognized by Android Studio

The Quick Fix That Resolved Everything #

After testing a few troubleshooting steps, this one command fixed the problem instantly:

flutter clean

Why This Worked (Likely Root Causes) #

While we can't confirm the exact issue without deeper log analysis, this kind of unexplained failure almost always traces back to corrupted or conflicting build caches:

• Damaged build artifacts: Previous builds may have left corrupted cache files in the project's build directory, causing Gradle to crash during the assembleDebug task
• Stale device connection cache: Flutter sometimes caches device connection state; if this cache glitches, it can fail to recognize a connected device even when it's active
• Temporary Gradle config conflicts: Minor dependency tweaks or project setting changes can leave Gradle in a broken state, and flutter clean wipes all these temporary states to start fresh

The flutter clean command deletes the project-wide build folder plus platform-specific build caches (like Android's .gradle directories), essentially resetting your project to a clean slate for building. It's the go-to fix for most weird, unexplained Flutter build failures.

内容的提问来源于stack exchange，提问作者nooxouille