Toast: basic usage.
Toast: self layout.
Style: 01, Android Style. 02, self-define style.
Theme: 01, Android Theme. 02, Self define Theme.
Search: dialog search.
Search: search widget.
Search: search history.
View: basic usage of self-define View.
View: invalidate self-define view.
View: onMeasure of self-define View.
DragAndDrop: simple example.