This app can help you to query when you start some apps, and find out it's activity name.
With four convenient query function, you can easy find out what you want.
You can also store, export thorse event to .csv file.
This is a usage of UsageStatsManager API, which is add after Android L.
Note: Android OS will clear usage event after 7 days, and some event older than 1 day might need a reboot to let it able to query.