Should I include the app's logo in a mobile app's action bar?

1. How do I add an icon to my action bar on Android?
2. What is the difference between app bar and nav bar?
3. What is action bar icon?

How do I add an icon to my action bar on Android?

Add Action Buttons

To add actions to the action bar, create a new XML file in your project's res/menu/ directory. The app:showAsAction attribute specifies whether the action should be shown as a button on the app bar.

What is the difference between app bar and nav bar?

Bottom app bars focus on actions while bottom navigation bars focus on navigation to top-level destinations that need to be accessible from anywhere in the app.

What is action bar icon?

The ActionBar, now known as the App Bar, is a consistent navigation element that is standard throughout modern Android applications. The ActionBar can consist of: An application icon. An "upward" navigation to logical parent. An application or activity-specific title.