Introduction to AWT Layout

• Layout means arranging the components within the container.

• The task of lay outing can be done automatically by the Layout manager.

• The layout manager is set by the setLayout( ) method.

• If no call to setLayout( ) is made, then the default layout manager is used.

• Whenever a container is resized (or sized for the first time), the layout manager is used to

• position each of the components within it.

Layout Manager is an interface that is implemented by all the classes of layoutmanagers. There are following classes that represents the layout managers:

•  FlowLayout

•  BorderLayout

•  GridLayout

•  CardLayout

•  GridBagLayout

• FlowLayout is the default layout manager.

• FlowLayout implements a simple layout style, which is similar to how words flow in a text editor.

• Components are laid out from the upper-left corner, left to right and top to bottom.

• When no more components fit on a line, the next one appears on the next line.

• A small space is left between each component, above and below,as well as left and right.

The BorderLayout class implements a common layout style for toplevel windows.

 It has four narrow, fixed-width components at the edges and one large area in the center.

 The four sides are referred to as

GridLayout lays out components in a two-dimensional grid.

 When we instantiate a GridLayout, we define the number of rows and columns.

• The CardLayout class is unique among the other layout managers in that it stores several different layouts.

• Each layout can be thought of as being on a separate index card in a deck that can be shuffled so that any card is on top at a given time.

• This can be useful for user interfaces with optional components that can be dynamically enabled and disabled upon user input.

• We can prepare the other layouts and have them hidden, ready to be activated when needed.

Each GridBagLayout object maintains a dynamic rectangular grid of cells, with each component occupying one or   more cells, called its display area.

Each component managed by a grid bag layout is associated with an instance of GridBagConstraints that specifies how the component is laid out within its display area.