Uninstall Xcode 4 when it was installed via the App Store
This help for Xcode before MAS install/Library/Developer/Shared/uninstall-devtools
If you install it from MAS you can remove from launchpad, but also need to remove some folders** and files created by this app, you can use some helper application that found this files and safely remove it :)
** ex.: ~/Library/Developer, ~/Library/Application Support/Xcode, ~/Library/iPhone Simulator, Logs and etc.
From the above comment, the correct way is to:
- Run sudo /Developer/Library/uninstall-devtools –mode=all
- Delete "/Applications/Install Xcode" if you want the app store to allow you to reinstall it.
If you have installed xcode from Mac App store, then you need to delete it from Launch pad. You can do this by locating xcode icon in launch pad, long click on the icon till it starts dancing. Then delete it and wait for a while till the xcode.app is deleted from /Application. If you manually delete xcode.app from /Application, App store will continue to think its installed and will not allow you to reinstall in future.