AWT Layout Managers

How Layout Managers Work

A layout manager positions and resizes components inside a container automatically, so the GUI survives window resizing. Set one with setLayout(manager).

FlowLayout

Places components left to right, wrapping when the edge is reached:

setLayout(new FlowLayout());
add(new Button("One"));
add(new Button("Two"));

BorderLayout

Five regions: NORTH, SOUTH, EAST, WEST, CENTER. The default for Frame.

setLayout(new BorderLayout());
add(new Button("Top"), BorderLayout.NORTH);
add(new Button("Center"), BorderLayout.CENTER);

GridLayout and CardLayout

// Equal cells in a grid
setLayout(new GridLayout(2, 3));

// Stacked cards, one visible at a time
setLayout(new CardLayout());

GridBagLayout

The most flexible manager: components specify grid cells, weights and fills with GridBagConstraints.

GridBagLayout gb = new GridBagLayout();
GridBagConstraints c = new GridBagConstraints();
setLayout(gb);
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 0; c.gridy = 0;
add(new Button("A"), c);

Key Points

• Layout managers resize components when the window changes size.
• Frame defaults to BorderLayout; Panel defaults to FlowLayout.
• GridBagLayout gives precise control for complex forms.