可拖拽文本範例

文件：

• draganddrop/draggabletext/draglabel.cpp
• draganddrop/draggabletext/draglabel.h
• draganddrop/draggabletext/dragwidget.cpp
• draganddrop/draggabletext/dragwidget.h
• draganddrop/draggabletext/main.cpp
• draganddrop/draggabletext/draggabletext.pro
• draganddrop/draggabletext/draggabletext.qrc