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COMPUTER SOFTWARE APPLICATION - CITS

Introduction to AWT Layouts

Introduction

Layout means the arrangement of components within the container. In other way we can say that placing the
components at a particular position within the container. The task of layouting the controls is done automatically
by the Layout Manager.

Layout Manager:-
The layout manager automatically positions all the components within the container. If we do not use layout
manager then also the components are positioned by the default layout manager. It is possible to layout the
controls by hand but it becomes very difficult because of the following two reasons.
1 It is very tedious to handle a large number of controls within the container.
2 Oftenly the width and height information of a component is not given when we need to arrange them
Java provide us with various layout manager to position the controls. The properties like size,shape and arrangement
varies from one layout manager to other layout manager. When the size of the applet or the application window
changes the size, shape and arrangement of the components also changes in response i.e. the layout managers
adapt to the dimensions of appletviewer or the application window.
The layout manager is associated with every Container object. Each layout manager is an object of the class that
implements the LayoutManager interface.
Following are the interfaces defining functionalities of Layout Managers.
Interface & Description
1 LayoutManager

The LayoutManager interface declares those methods which need to be implemented by the class whose object
will act as a layout manager.
2 LayoutManager2

The LayoutManager2 is the sub-interface of the LayoutManager.This interface is for those classes that know how
to layout containers based on layout constraint object.
AWT Layout Manager Classes:
Following is the list of commonly used controls while designed GUI using AWT.

LayoutManager & Description
1 BorderLayout
The borderlayout arranges the components to fit in the five regions: east, west, north, south and center.
2 CardLayout
The CardLayout object treats each component in the container as a card. Only one card is visible at a time.

3 FlowLayout
The FlowLayout is the default layout.It layouts the components in a directional flow.
4 GridLayout
The GridLayout manages the components in form of a rectangular grid.

5 GridBagLayout
This is the most flexible layout manager class.The object of GridBagLayout aligns the component
vertically,horizontally or along their baseline without requiring the components of same size.

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CITS : IT&ITES - Computer Software Application - Lesson 116 - 119