The module of the Run button app in Android Studio shows the Red Fork

app出现红叉提示找不到Android SDK

I. Direct and effective

1.              ?File -> Invalidate Caches -> Invalidate2.              ?File -> Close Project.3.              ?Remove the project from the AS project selector window.4.              ?Quit from Android Studio5.              ?Start AS and open project again

Ii. Fundamental Analysis

Item switch to: Project mode, in the app module found a file name: App.iml file, click Ctrl+f, Search Jdkname, if the dependency here is not the Android SDK related, it is probably the problem here, normal is this:

   <orderEntry type="jdk" jdkName="Android API 27 Platform" jdkType="Android SDK" />改成你自己的“Platform”就可以了。   

The project may have referenced other plug-ins, such as Kotlin and Java hybrid development, when built in a Mac environment, the Jdkname in the iML file becomes the Kotlin SDK, causing the project's app to find a red Cross without the Android SDK.

The module of the Run button app in Android Studio shows the Red Fork