Error:
Invalid command android
UnityEditor.HostView:OnGUI()
CommandInvokationFailure:
Unable to list target platforms. Ple
These are the steps that eventually worked for me...
Install JDK jdk1.8.0_131 (yes, this specific version, not a later version) and set it as the JDK Path in Unity.
Delete android sdk tools folder : [android_sdk_root]/tools
Download SDK Tools v25.2.5 (this specific version) from http://dl-ssl.google.com/android/repository/tools_r25.2.5-windows.zip
Extract the tools folder in that archive to Android SDK root
Build your project