Common properties of view
1. The width and height of the control
android:layout_width="30dp"
android:layout_height="30dp"
Values can be:
wrap_content
match_parent
dp value
2. Visibility of controls: (three states)
android:"visible"
Optional values:
visible
invisible Invisible, occupying position
gone is invisible and does not take up space
3. The background of the control: (color, picture)
android:background="#F00"
optional value
color value
Transparency can be enacted
picture
margin and padding