GUI

1.package:

android.widget，

android.view :ViewGroup

     /                  \

View            ViewGroup

子组件分布依赖于ViewGroup.LayoutParams,ViewGroup.MarginLayoutParams

recommend layout：XML布局

setContentView(R.layout.<source name>);

findViewById(R.id.<android.id attribute>);

2.Layout way:

LinearLayout:TableLayout:Shrinkable,Stretchable,Collapsed

FrameLayout

RelativeLayout

GridLayout

AbsoluteLayout