What is the structure of the Android PackageManagerService?

I would like to know , what are the sequence of steps that happen once t开发者_C百科he user clicks on the "installApp"??

I need to disable the installation of apps(when user tries to install the app by clicking on install), based on certain conditions, how can i do it?? Any suggestions will help.Thank you.

You have no control over the installation process. If there is an APK, the user can install it, and your code will not be executed until the installation is complete.