Java awt

JAVA
AWT
Prepared by
Miss. Arati A. Gadgil

•Java AWT (Abstract Windowing Toolkit) is an API to develop
GUI or window-based application in java.
•Java AWT components are platform-dependent i.e. components
are displayed according to the view of operating system. AWT is
heavyweight i.e. its components uses the resources of system.
•The java.awt package provides classes for AWT api such as
TextField, Label, TextArea, RadioButton, CheckBox, Choice,
List etc.
AWT
2

Container
The Container is a component in AWT that can contain another
components like buttons, textfields, labels etc. The classes that extends
Container class are known as container such as Frame, Dialog and Panel.
Window
The window is the container that have no borders and menu bars. You
must use frame, dialog or another window for creating a window
Panel
The Panel is the container that doesn't contain title bar and menu bars. It
can have other components like button, textfield etc.
Frame
The Frame is the container that contain title bar and can have menu bars.
It can have other components like button, textfield etc.
4

5
Useful Methods of Component class
public void add(Component c)
inserts a component on this component
public void setSize(int width,int height)
sets the size (width and height) of the component.
public void setLayout(LayoutManager m)
defines the layout manager for the component.
public void setVisible(boolean status)
changes the visibility of the component, by default false.

import java.awt.*;
class frm1 extends Frame
{
frm1(String s)
{
super(s);
setSize(400,400);
setVisible(true);
}
public static void main(String []ar)
{
frm1 a=new frm1("first
window");
}
}
First frame
Output
6

import java.awt.*;
class First extends Frame
{
First()
{
Button b=new Button("click me");
b.setBounds(30,100,80,30) ;// setting button position
add(b);//adding button into frame
setSize(300,300);//frame size 300 width and 300 height
setLayout(null);//no layout manager
setVisible(true);//now frame will be visible, by default not
visible
}
public static void main(String args[])
{
First f=new First();
}
} 7

Output
The setBounds(int xaxis, int yaxis, int width,
int height)
Method is used in the above example that sets
the position of the awt button.
b.setBounds(30,100,80,30)
8

Changing the state of an object is known as an
event. For example, click on button, dragging
mouse etc. The java.awt.event package provides
many event classes and Listener interfaces for
event handling.
Event Classes Listener Interfaces
ActionEvent ActionListener
MouseEvent MouseListener and
MouseMotionListener
MouseWheelEvent MouseWheelListener
KeyEvent KeyListener
ItemEvent ItemListener
TextEvent TextListener
AdjustmentEvent AdjustmentListener
WindowEvent WindowListener
ComponentEvent ComponentListener
ContainerEvent ContainerListener
FocusEvent FocusListener
Event and Listener (Java Event Handling)
9

import java.awt.*; import java.awt.event.*;
class eventi extends Frame implements
ActionListener
{ TextField tf;
eventi()
{
tf=new TextField();
tf.setBounds(60,50,170,20);
Button b=new Button("click me");
b.setBounds(100,120,80,30);
b.addActionListener(this);
add(b);add(tf);
setSize(300,300);
setLayout(null);
setVisible(true);
}
public void actionPerformed(ActionEvent
e)
{ tf.setText("Welcome");
}
public static void main(String args[])
{ new eventi();
}
10

AWT UI Elements
Label
constructors
Label() Constructs an empty label.
Label(String text) Constructs a new label with the specified
string of text, left justified.
Label(String text, int alignment)
Constructs a new label that presents the specified string of
text with the specified alignment.
static int CENTER -- Indicates that the label should be centered.
static int LEFT -- Indicates that the label should be left justified.
static int RIGHT -- Indicates that the label should be right justified
11

Methods
int getAlignment()
Gets the current alignment of this label.
String getText()
Gets the text of this label.
void setAlignment(int alignment)
Sets the alignment for this label to the specified alignment.
void setText(String text)
Sets the text for this label to the specified text
12

Button
Constructors
Button()
Constructs a button with an empty string for its
label.
Button(String text)
Constructs a new button with specified label.
13

Methods
void addActionListener(ActionListener l) Adds the specified action
listener to receive action events from this button.
String getActionCommand()
Returns the command name of the action event fired by this button.
String getLabel()
Gets the label of this button
void removeActionListener(ActionListener l)Removes the specified
action listener so that it no longer receives action events from this button
void setActionCommand(String command)
Sets the command name for the action event fired by this button.
void setLabel(String label)
Sets the button's label to be the specified string 14

CheckBox
Constructors
Checkbox()
Creates a check box with an empty string for its label.
Checkbox(String label, boolean state) Creates a check box with
the specified label and sets the specified state.
Checkbox(String label, boolean state, CheckboxGroup group)
Constructs a Checkbox with the specified label, set to the specified
state, and in the specified check box group.
Checkbox(String label, CheckboxGroup group, boolean state)
Creates a check box with the specified label, in the specified check
box group, and set to the specified state.
15

void addItemListener(ItemListener l)
Adds the specified item listener to receive item events from this
check box.
CheckboxGroup getCheckboxGroup()
Determines this check box's group.
String getLabel()
Gets the label of this check box
boolean getState()
Determines whether this check box is in the on or off state.
void setCheckboxGroup(CheckboxGroup g)
Sets this check box's group to the specified check box group.
void setState(boolean state)
Sets the state of this check box to the specified state. 16

List
The List represents a list of text items. The list can be configured to that
user can choose either one item or multiple items.
Constructors
List()
Creates a new scrolling list.
List(int rows) Creates a new scrolling list initialized with the specified
number of visible lines
List(int rows, boolean multipleMode)
Creates a new scrolling list initialized to display the specified
number of rows.
17

void add(String item)
Adds the specified item to the end of scrolling list.
void add(String item, int index) Adds the specified item to the the
scrolling list at the position indicated by the index.
void addActionListener(ActionListener l) Adds the specified
action listener to receive action events from this list
void clear()
Deprecated. As of JDK version 1.1, replaced by removeAll().
void delItem(int position)
Deprecated. replaced by remove(String) and remove(int).
void deselect(int index)
Deselects the item at the specified index.
18

String getItem(int index)
Gets the item associated with the specified index.
int getItemCount()
Gets the number of items in the list
String[] getItems()
Gets the items in the list.
int getRows()
Gets the number of visible lines in this list
int getSelectedIndex()
Gets the index of the selected item on the list
19

boolean isMultipleMode()
Determines whether this list allows multiple selections.
void remove(int position)
Removes the item at the specified position from this scrolling
list.
void remove(String item)
Removes the first occurrence of an item from the list
20

TextField
Constructor
TextField()
Constructs a new text field.
TextField(int columns)
Constructs a new empty text field with the specified number of
columns.
TextField(String text)
Constructs a new text field initialized with the specified text.
TextField(String text, int columns)
Constructs a new text field initialized with the specified text to be
displayed, and wide enough to hold the specified number of
columns. 21

void addActionListener(ActionListener l)
Adds the specified action listener to receive action
events from this text field.
int getColumns()
Gets the number of columns in this text field
void setColumns(int columns)
Sets the number of columns in this text field
void setText(String t)
Sets the text that is presented by this text component
to be the specified text.
22

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