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

How to Use FlowLayout

The FlowLayout (in the API reference documentation) class provides a very simple layout manager that is used, by default, by JPanels. Here's an applet that shows a flow layout in action:

Click this figure to run the applet.
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.

FlowLayout puts components in a row, sized at their preferred size. If the horizontal space in the container is too small to put all the components in one row, FlowLayout uses multiple rows. Within each row, components are centered (the default), left-aligned, or right-aligned as specified when the FlowLayout is created.

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

Container contentPane = getContentPane();
contentPane.setLayout(new FlowLayout());

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 FlowLayout API

The FlowLayout class has three constructors:
public FlowLayout()
public FlowLayout(int alignment)
public FlowLayout(int alignment,
                  int horizontalGap, int verticalGap)
The alignment argument must have the value FlowLayout.LEFT, FlowLayout.CENTER, or FlowLayout.RIGHT. The horizontalGap and verticalGap arguments specify the number of pixels to put between components. If you don't specify a gap value, FlowLayout uses 5 for the default gap value.

Examples that Use FlowLayout

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

Example Where Described Notes
FlowWindow This page Sets up a content pane to use FlowLayout.
ButtonDemo How to Use Buttons, Check Boxes, and Radio Buttons (in the Creating a GUI with JFC/Swing trail) Uses the default FlowLayout of a JPanel.

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