http://www.uml.org.cn/mobiledev/201209102.asp
1、View
View
extends Object
implements Drawable.Callback KeyEvent.Callback AccessibilityEventSource
java.lang.Object
android.view.View
- Known Direct Subclasses（直接子类，SurfaceView是View的子类）
AnalogClock,ImageView,KeyboardView,MediaRouteButton,ProgressBar,Space,SurfaceView,TextView,TextureView,ViewGroup,ViewStu
- Known Indirect Subclasses（间接子类）
AbsListView,AbsSeekBar,AbsSpinner,AbsoluteLayout,AdapterView<T extends Adapter>,AdapterViewAnimator,AdapterViewFlipper,AppWidgetHostView,AutoCompleteTextView, Button, CalendarView, CheckBox, CheckedTextView, Chronometer, and 53 others.
Class Overview
This class represents the basic building block for user interface components. A View occupies a rectangular area on the screen and is responsible for drawing and event handling. View is the base class forwidgets, which are used to create interactive UI components (buttons, text fields, etc.). TheViewGroup subclass is the base class forlayouts, which are invisible containers that hold other Views (or other ViewGroups) and define their layout properties.
View类为用户界面提供了最基础的组件，View类组件负责更换屏幕与处理事件。同时，View类也是widgets类的基础类，widgets类可以创建基础的UI组件，如Bottons、Textview等等。View类的其中一个直接子类ViewGroup是layous的基础类，layous是用来装载View或者其他的ViewGrous的，并且可以定义这些装载内容的特性。
2、 从上述的Overview可知，SurfaceView是继承于View类的，（GLSurfaceView是继承于SurfaceView的）
