Android.intent.category.LAUNCHER and Android.intent.action.MAIN

An application can have more than one activity, and each activity is at the same level, which activity is started first when the program is started?

Some programs may need to be displayed in the list of programs, some of which are not required. How do you define it?

Android.intent.action.MAIN
Determine the activity that the application starts first

Android.intent.category.LAUNCHER
Determine if the application appears in the program list

As long as there is such a intent-filter in the XML configuration file, and there is this launcher in it, then this activity is the activity that first runs when the program is clicked.