The JavaTM Tutorial

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Trail: Creating a GUI with JFC/Swing
Lesson: Laying Out Components Within a Container

## How to Use BorderLayout

> Here's an applet that shows a `BorderLayout` in action.

> This is a picture of the applet's GUI. To run the applet, click the picture. The applet will appear in a new browser window.

> As the preceding applet shows, a `BorderLayout` has five areas: north, south, east, west, and center. If you enlarge the window, the center area gets as much of the available space as possible. The other areas expand only as much as necessary to fill all available space. Often, a container uses only one or two of the areas of the `BorderLayout` -- just the center, or center and south, for example.

> The following code creates the `BorderLayout` and the components it manages. You can find the whole program in `BorderWindow.java`. The program runs either within an applet (with the help of `AppletButton`) or as an application.

> >     Container contentPane = getContentPane();
> >     //Use the content pane's default BorderLayout.
> >     //contentPane.setLayout(new BorderLayout()); //unnecessary

> >     contentPane.add(new JButton("Button 1 (NORTH)"),
> >                     BorderLayout.NORTH);
> >     contentPane.add(new JButton("2 (CENTER)"),
> >                     BorderLayout.CENTER);
> >     contentPane.add(new JButton("Button 3 (WEST)"),
> >                     BorderLayout.WEST);
> >     contentPane.add(new JButton("Long-Named Button 4 (SOUTH)"),
> >                     BorderLayout.SOUTH);
> >     contentPane.add(new JButton("Button 5 (EAST)"),
> >                     BorderLayout.EAST);

> > Important: When adding a component to a container that uses `BorderLayout`, specify the component's location as one of the arguments to the `add` method. Do not rely on the component being added to the center, by default. If you find that a component is missing from a container controlled by a `BorderLayout`, make sure that you specified the component's location and that you didn't put another component in the same location.

> All our examples that use `BorderLayout` specify the component as the first argument to the `add` method. For example:

> >     add(component, BorderLayout.CENTER)  //preferred

> However, you might see code in other programs that specifies the component second. For example, the following are alternate ways of writing the preceding code:

> >     add(BorderLayout.CENTER, component)  //valid but old-fashioned
> >         or
> >     add("Center", component)             //valid but error prone

### The BorderLayout API

> By default, a `BorderLayout` puts no gap between the components it manages. In the preceding applet, any apparent gaps are the result of the buttons reserving extra space around their apparent display area. You can specify gaps (in pixels) using the following constructor:

> >     BorderLayout(int horizontalGap, int verticalGap)

> You can also use the following methods to set the horizontal and vertical gaps, respectively:

> >     void setHgap(int)
> >     void setVgap(int)

### Examples that Use BorderLayout

> The following table lists some of the many examples that use `BorderLayout`.

> Example | Where Described | Notes
> --- | --- | ---
> `BorderWindow` | This page | Puts a component in each of the five possible locations.
> `TabbedPaneDemo` | How to Use Tabbed Panes | One of many examples that puts a single component in the center of a content pane, so that the component is as large as possible.
> `CheckBoxDemo` | How to Use Check Boxes | Creates a `JPanel` that uses a `BorderLayout`. Puts components into the west and center locations.

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