How to show item icons on Android toolbar

you need to add this to your xml menu

xmlns:app="http://schemas.android.com/apk/res-auto"

      

        
        
        
      

    

then it android:showAsAction="always"

should look like this:

app:showAsAction="always"

      

        
        
        
      

    

the final conclusion will be something like this

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <item android:id="@+id/bno_bookmark"
        android:visible="true"
        android:title="@string/disable_draw"
        android:icon="@drawable/ic_pen"
        app:showAsAction="always">
    </item>
</menu>