Laying Out Components Within a Container

How to Use GridLayout

Here's an applet that shows a GridLayout 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.

A GridLayout places components in a grid of cells. Each component takes all the available space within its cell, and each cell is exactly the same size. If you resize the GridLayout window, you'll see that the GridLayout changes the cell size so that the cells are as large as possible, given the space available to the container.

Below is the code that creates the GridLayout and the components it manages. You can find the whole program in GridWindow.java. The program runs either within an applet (with the help of AppletButton) or as an application.

Container contentPane = getContentPane();

contentPane.setLayout(new GridLayout(0,2));

contentPane.add(new JButton("Button 1"));
contentPane.add(new JButton("2"));
contentPane.add(new JButton("Button 3"));
contentPane.add(new JButton("Long-Named Button 4"));
contentPane.add(new JButton("Button 5"));

The constructor tells the GridLayout class to create an instance that has two columns and as many rows as necessary.

The GridLayout API

The GridLayout class has two constructors:

public GridLayout(int rows, int columns)
public GridLayout(int rows, int columns,
                  int horizontalGap, int verticalGap)

At least one of the rows and columns arguments must be nonzero. The horizontalGap and verticalGap arguments to the second constructor allow you to specify the number of pixels between cells. If you don't specify gaps, their values default to zero. In the applet above, any apparent gaps are the result of the buttons reserving extra space around their apparent display area.

Examples that Use GridLayout

The following table lists some of the examples that use grid layout.

Example	Where Described	Notes
GridWindow.java	This page	Uses a 2-column grid.
LabelDemo.java	How to Use Labels	Uses a 3-row grid.
Converter.java	The Anatomy of a Swing-Based Application	Uses the 4-argument GridLayout constructor.

Laying Out Components Within a Container