Duration: 16:35 min
Summary: In this lesson, we will talk about two things: toggling system visibility and adding views dynamically. First, we will create a button centered in the middle of the activity. When the user clicks on the button the system visibility is toggled on and off. Second, we will add a button to the top of the activity. When the user clicks on the button, we will create a new button and add it to the current layout. When the user clicks on the newly created button, we will remove it from the layout.