I know how to add Splash Screen for Web exported version but don’t know how to add it in Android exported version?
On Web cocos creator uses simple HTML page to show the game loading progress but how to achieve the same thing on Android…Do I need to implement it in C++ and listen for the event when the loading is done progressing?
Do you want the correct Android app way, then you should follow: https://plus.google.com/u/0/+AndroidDevelopers/posts/Z1Wwainpjhd. Everything else is just a faked splash/launch screen. Your idea with a custom scene should be followed after the official launch screen.
Maybe @slackmoehrle can discuss with the team, if they want to implement a sample in the template, like in the iOS app.