- Positioning various GUI components
- In order to organized
the GUI components in graphical user interfaces,
you need to
control
the placement of the components
inside a
container
(i.e., inside a JPanel or inside the contentPane of a JFrame )
- A layout manager is a Java object to help you organize components added onto a panel
- In order to organized
the GUI components in graphical user interfaces,
you need to
control
the placement of the components
inside a
container
- Java provide are many different
layout managers
Some examples:
- FlowLayout:
lines components up in a row -
click here
- BorderLayout: put components in
a square at one of the position of
North, South, East, West and Center -
click here
- GridLayout:
put components into a rectangular grid -
click here
- BoxLayout:
a picture paints a thousand words, here, take a look:
click here
- CardLayout:
a picture paints a thousand words, here, take a look:
click here
- GridBag:
a picture paints a thousand words, here, take a look:
click here
- I will only discuss the first 3 layout managers, but
once you understand the principle, it is easy to learn
to use the other ones.
- To learn more about Layout Manager, here is an online tutorial available at Sun MicroSystems: click here
- FlowLayout:
lines components up in a row -
click here
- To select a
layout manager
for a container object
(JPanel or the contentPane of a JFrame):
ContainerObject.setLayout( new LayoutManagerName( parameters ) );
- How to select a layout manager
for a JPanel:
JPanel MyPanel = new JPanel(); MyPanel.setLayout( new LayoutManagerName(...) );
- How to select a layout manager
for a JFrame:
JFrame MyFrame = new JFrame(); MyFrame.getContentPane().setLayout( new LayoutManagerName(...) );
- Default layout manager:
- Each container
JPanel and
JFrame)
component
has a
default layout manager
- If you do not select a layout manager, then the container (JPanel or JFrame) object will use the default layout manager
- The default layout managers:
- For the
contentPane of a JFrame is
the Border Layout Manager :
- For a JPanel is the
Flow Layout Manager :
- For the
contentPane of a JFrame is
the Border Layout Manager :
- Each container
JPanel and
JFrame)
component
has a
default layout manager
I will now show you how to use 3 of these layout managers
- You don't
need to learn
how to use layout managers
on the
contentPane
of a JFrame
- Programming Trick:
- Create one
top-level JPanel
- Then create/use as many JPanel objects as you need to organize your components.
- Stick (add) all the "organizational" JPanels onto the top-level JPanel
- Stick (add) the top-level JPanel into the Center position of contentPane of the JFrame (using the default Border Layout Manager of contentPane)
- Then create/use as many JPanel objects as you need to organize your components.
- Create one
top-level JPanel
|
|