1. What is UI? ?
UI is the component that the user can see and interact with.
2.View is a rectangular area on the screen, responsible for drawing and event handling; it is the base class of controls (widget).
3.ViewGroup is a subclass of View, which is an invisible container responsible for managing other Views and their layout properties; it is the base class for layout and view containers
4. What is a layout?
The layout
is an invisible container (ViewGroup)
Define the visual structure of the UI
Define the size and position of child elements through layout parameters (LayoutParams)
5. View inheritance structure:
6. Some basic controls and their uses
TextView displays text
ImageView displays pictures
EditText input box, you can set the pop-up method of the soft keyboard
Button button
checkBox checkbox
RadioButton radio button, generally used with RadioGroup
There are many more that are not listed one by one. . .
7. View properties (how to use)
8. Properties of TextView:
