Creating and Enriching Graphical User Interfaces - Beginning Java 7 - page 590

Button btnYes = new Button("Yes");
Note Iliketoprefixacomponentvariabletoindicateitskind.Forexample,Iprefix
buttons with btn .
Containers Overview
Buttons,labels,textfields,andothercomponentscannotbeplaceddirectlyonthescreen;
they need to be placed in a container window that is placed directly on the screen.
AWT provides several container classes in the java.awt package. Figure 7-3
presents their hierarchy.
Figure 7-3. AWT's container class hierarchy is rooted in Container .
AWT's Container classistherootclassforallAWTcontainers.Directlybeneath
Container are Panel , ScrollPane , and Window :
• Panel isthesimplestcontainer.Itprovidesspaceinwhichanapplicationcan
attach any other component, including other panels.
• ScrollPane implements automatic horizontal and/orvertical scrolling fora
single child (contained) component. A container that contains a component is
referred to as that component's parent .
• Window isatop-levelwindowwithnoborders.Its Dialog subclassdescribes
a dialog box (awindowforsolicitinginputfromtheuser)andits Frame sub-
class describes a frame window (a top-level window with borders, including a
titlebar). Dialog 's FileDialog subclass describes a dialog box for select-
ing a file.
Container declaresmanycontainer-orientedmethods.Forexample, Component
add(Component comp) appends component comp to the container, Compon-