How to get application open and close time for all installed application

How can I get open and close time for all installed 开发者_如何学运维app. I have to create a app that will calculate app usages statics on phone.

Thanks, Ajay

On the application level you would need to run a service that periodically checks and tracks statistics itself. At the platform level, you should be able to easily make modifications to track this fairly accurately..

I donot think it is at all possible.