錯誤描述：

Warning! This package referenced a Flutter repository via the .packages file that is no longer available. The repository from which the 'flutter' tool is currently executing will be
used instead.
  running Flutter tool: /Users/sunyd/Desktop/DevelopTool/flutter
  previous reference  : /Users/sunyd/Desktop/DevelopTool/flutter-stable
This can happen if you deleted or moved your copy of the Flutter repository, or if it was on a volume that is no longer mounted or has been mounted at a different location. Please
check your system path to verify that you are running the expected version (run 'flutter --version' to see which flutter is on your path).

起因：
本地使用的flutter sdk版本是1.9.1。想體驗(yàn)下官方的最新版本，所有在現(xiàn)有的flutter 同級目錄，下載了官方stable分支下的最新版本。
但是打開現(xiàn)有錯誤卻報(bào)錯了。

錯誤位置：
通過錯誤提示可以看出.packages文件出了問題。

打開.packages文件，發(fā)現(xiàn)工程中的員sdk路徑都變成了新的。

解決方案一：
（我沒有嘗試，因?yàn)檫@樣會重新下載所有插件依賴。對于我們的項(xiàng)目來說很多插件不好下載。）
刪除.packages重新build。

解決方案二：
（解決我的問題）
打開.packages，將新的flutter sdk路徑，全局替換成之前的路徑。