Abstract Window Toolkit_Event Handling_python

AWT Classes
• The classes and interfaces of the AWT are
used to develop stand alone applications and
to implement the GUI controls used by
Applets.

Window Fundamentals
• The AWT defines windows according to a class
hierarchy that adds functionality and
specificity with each level.
• The two most common windows are:
1. Panel, which is used by applets
2. Derived from Frame, which creates a
standard application window.

Frame
• Subclass of window and has a title bar,
menubar, borders and resizing corners.
• Creating Frame:
Frame f1=new Frame();
Frame f2=new Frame(“New Example”);

Frame: Setting Window’s Dimensions
void setSize(int width, int height)
void setSize(Dimension size)

Frame: Hiding and Showing
Syntax: void setVisible(boolean)
Example: void setVisible(true);
Frame: Setting Windows Title
Syntax:void setTitle(String title)
Example: void setTitle(New Example);

Closing the Frame Window
void windowClosing();

Write a program to display a frame with a button. The caption of the button should be “Change Color”. For every click of the button, the background color of the
frame should change randomly.
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import java.util.*;
public class ButtonFrame extends Frame
implements ActionListener
{
Button b;
Random rand;
Color c;

public ButtonFrame()
{
addWindowListener(new MyWindowAdapter());
b=new Button("Change Color");
b.addActionListener(this);
add(b);
rand=new Random();
}
public void paint(Graphics g)
{ }

public static void main(String args[])
{
ButtonFrame ob= new ButtonFrame();
ob.setSize(new Dimension(300, 200));
ob.setTitle("An AWT-Based Application--Buttons in
frame");
ob.setLayout(new FlowLayout());
ob.setVisible(true);
}

public void actionPerformed(ActionEvent ie)
{
//repaint();
float r=rand.nextFloat();
float gr=rand.nextFloat();
float b=rand.nextFloat();
c=new Color(r,gr,b);
setBackground(c);
}
}

class MyWindowAdapter extends WindowAdapter
{
public void windowClosing(WindowEvent we)
{
System.exit(0);
}
}

Layout Manager
• The Layout Managers are used to arrange
controls in a particular manner.
• Layout Manager is an interface that is
implemented by all the classes of layout
managers.

Types of Layout Manager
• Flow Layout
• Grid Layout
• Border Layout
• CardLayout

Fields of FlowLayout
• public static final int LEFT
• public static final int RIGHT
• public static final int CENTER
• public static final int LEADING
• public static final int TRAILING

Flow Layout
• The FlowLayout is used to arrange the components in a
line, one after another (in a flow).
• It is the default layout of applet or panel.
Constructors of FlowLayout class
 FlowLayout(): creates a flow layout with centered
alignment and a default 5 unit horizontal and vertical gap.
 FlowLayout(int align): creates a flow layout with the given
alignment and a default 5 unit horizontal and vertical gap.
 FlowLayout(int align, int hgap, int vgap): creates a flow
layout with the given alignment and the given horizontal
and vertical gap.

Flow Layout - Example
import java.awt.*;
public class MyFlowLayout
{
Frame f=new Frame();
MyFlowLayout()
{
Button b1=new Button("1");
f.add(b1);f.add(b2);f.add(b3);f.add(b4);f.add(b5);
f.setLayout(new FlowLayout(FlowLayout.RIGHT));
//setting flow layout of right alignment
f.setSize(300,300);
f.setVisible(true);
}
public static void main(String[] args)
{
MyFlowLayout= new MyFlowLayout();
} }

GridLayout
• The GridLayout is used to arrange the components in
rectangular grid.
• Constructors of GridLayout class
GridLayout(): creates a grid layout with one column
per component in a row.
GridLayout(int rows, int columns): creates a grid
layout with the given rows and columns but no gaps
between the components.
GridLayout(int rows, int columns, int hgap, int vgap):
creates a grid layout with the given rows and columns
alongwith given horizontal and vertical gaps.

GridLayout
import java.awt.*;
public class MyGridLayout
{
Frame ff=new Frame();;
MyGridLayout(){
f.add(b1);f.add(b2);f.add(b3);f.add(b4);f.add(b5);
f.add(b6);f.add(b7);f.add(b8);f.add(b9);
f.setLayout(new GridLayout(3,3));
//setting grid layout of 3 rows and 3 columns
f.setSize(300,300);
f.setVisible(true);
}
{
MyGridLayout= new MyGridLayout();
} }

BorderLayout
• The BorderLayout is used to arrange the
components in five regions: north, south, east,
west and center.
• Each region (area) may contain one
component only.
• It is the default layout of frame or window

Constructors - BorderLayout
public static final int NORTH
public static final int SOUTH
public static final int EAST
public static final int WEST
public static final int CENTER
Constructors of BorderLayout class:
BorderLayout(): creates a border layout but with no gaps
BorderLayout(int hgap, int vgap): creates a border
layout with the given horizontal and vertical gaps

Example - BorderLayout
import java.awt.*;
import javax.swing.*;
public class Border {
Frame f;
Border()
{
f=new Frame();
Button b1=new Button("NORTH");;
Button b2=new Button("SOUTH");;
Button b3=new Button("EAST");;
Button b4=new Button("WEST");;
Button b5=new Button("CENTER");;

BorderLayout
f.add(b1,BorderLayout.NORTH);
f.add(b2,BorderLayout.SOUTH);
f.add(b3,BorderLayout.EAST);
f.add(b4,BorderLayout.WEST);
f.add(b5,BorderLayout.CENTER);
f.setSize(300,300);
f.setVisible(true);
}
{
new Border();
}
}

Control Fundamentals
• Button
• Label
• CheckBox
• List
• MenuBar

AWT Button Example with ActionListener
import java.awt.*;
public class ButtonExample {
public static void main(String[] args) {
Frame f=new Frame("Button Example");
TextField tf=new TextField();
tf.setBounds(50,50, 150,20);
Button b=new Button("Click Here");
b.setBounds(50,100,60,30);
b.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
tf.setText("Welcome to Javatpoint.");
}
});
f.add(b);f.add(tf);
f.setSize(400,400); > javac ButtonExample.java
>java ButtonExample
f.setLayout(null);
f.setVisible(true);
}
}

AWT TextField Example with ActionListener
import java.awt.*;
public class TextFieldExample extends Frame implements ActionListener{
TextField tf1,tf2,tf3;
Button b1,b2;
TextFieldExample(){
tf1=new TextField();
tf1.setBounds(50,50,150,20);
tf2.setBounds(50,100,150,20);
tf3.setBounds(50,150,150,20);
tf3.setEditable(false);
b1=new Button("+");
b1.setBounds(50,200,50,50);
b2=new Button("-");
b2.setBounds(120,200,50,50);
b1.addActionListener(this);
b2.addActionListener(this);

add(tf1);add(tf2);add(tf3);add(b1);add(b2);
setSize(300,300);
setLayout(null);
setVisible(true);
}
public void actionPerformed(ActionEvent e) {
String s1=tf1.getText(); s1=“10” =10
String s2=tf2.getText(); s2=“5” =5
int a=Integer.parseInt(s1);
int b=Integer.parseInt(s2);
int c=0;
if(e.getSource()==b1){
c=a+b;
}else if(e.getSource()==b2){
c=a-b;
}
String result=String.valueOf(c);
tf3.setText(result);
}
new TextFieldExample();
}
}

TextArea
import java.awt.*;
public class TextAreaExample extends Frame implements ActionListener{
Label l1,l2;
TextArea area;
Button b;
TextAreaExample(){
l1=new Label();
l1.setBounds(50,50,100,30);
l2=new Label();
l2.setBounds(160,50,100,30);
area=new TextArea();
area.setBounds(20,100,300,300);
b=new Button("Count Words");
b.setBounds(100,400,100,30);
b.addActionListener(this);
add(l1);add(l2);add(area);add(b);
setSize(400,450);
setLayout(null);
setVisible(true);
}

public void actionPerformed(ActionEvent e){
String text=area.getText();
String words[]=text.split("s");
l1.setText("Words: "+words.length);
l2.setText("Characters: "+text.length());
}
new TextAreaExample();
}
}

Choice Example with ActionListener
import java.awt.*;
public class ChoiceExample
{ ChoiceExample(){
Frame f= new Frame();
Label label = new Label();
label.setAlignment(Label.CENTER);
label.setSize(400,100);
Button b=new Button("Show");
b.setBounds(200,100,50,20);
Choice c=new Choice();
c.setBounds(100,100, 75,75);
c.add("C");
c.add("C++");
c.add("Java");
c.add("PHP");
c.add("Android");
f.add(c);f.add(label); f.add(b);

Choice Example with ActionListener
f.setSize(400,400);
f.setLayout(null);
f.setVisible(true);
b.addActionListener(new ActionListener()
{public void actionPerformed(ActionEvent e)
{
String data = "Programming language Selected: "+
c.getItem(c.getSelectedIndex());
label.setText(data);
}
});
}
{
new ChoiceExample();
}
}

Java AWT List Example with ActionListener
import java.awt.*;
public class ListExample
{ ListExample(){
Label label = new Label();
label.setAlignment(Label.CENTER);
label.setSize(500,100);
Button b=new Button("Show");
b.setBounds(200,150,80,30);
List l1=new List(4, false);
l1.setBounds(100,100, 70,70);
l1.add("C");
l1.add("C++");
l1.add("Java");
l1.add("PHP");
final List l2=new List(4, true);
l2.setBounds(100,200, 70,70);
l2.add("Turbo C++");
l2.add("Spring");
l2.add("Hibernate");

Java AWT List Example with ActionListener
l2.add("CodeIgniter");
f.add(l1); f.add(l2); f.add(label); f.add(b);
f.setSize(450,450);
f.setLayout(null);
f.setVisible(true);
b.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String data = "Programming language Selected: "+l1.getItem(l1.getSelectedIndex());
data += ", Framework Selected:";
for(String frame:l2.getSelectedItems()){
data += frame + " ";
}
label.setText(data);
}
});
}
{
new ListExample();
} }

Java AWT MenuItem and Menu
import java.awt.*;
class MenuExample
{
MenuExample(){
Frame f= new Frame("Menu and MenuItem Example");
MenuBar mb=new MenuBar();
Menu m=new Menu("Menu");
Menu sm=new Menu("Sub Menu");
MenuItem i1=new MenuItem("Item 1");
m.add(i1);
m.add(i2);
m.add(i3);
sm.add(i4);
sm.add(i5);

Java AWT MenuItem and Menu
m.add(sm);
mb.add(m);
f.setMenuBar(mb);
f.setSize(400,400);
f.setLayout(null);
f.setVisible(true);
}
{
MenuExample me= new MenuExample();
}
}

Java AWT Dialog
• The Dialog control represents a top level
window with a border and a title used to take
some form of input from the user. It inherits
the Window class.
• Unlike Frame, it doesn't have maximize and
minimize buttons.

Java AWT Dialog
import java.awt.*;
public class DialogExample {
private static Dialog d;
DialogExample() {
d = new Dialog(f , "Dialog Example", true);
d.setLayout( new FlowLayout() );
Button b = new Button ("OK");
b.addActionListener ( new ActionListener()
{
public void actionPerformed( ActionEvent e )
{
DialogExample.d.setVisible(false);
}
});

Java AWT Dialog
d.add( new Label ("Click button to continue."));
d.add(b);
d.setSize(300,300);
d.setVisible(true);
}
{
new DialogExample();
}
}

FileNameFilter - Interface
import java.io.*;
• FileNameFilter interface has method
• boolean accept(File dir, String name)
• Should be implemented and every file is
tested for this method to be included in the
file list.

Java Swings
 Java Swing is a lightweight Graphical User
Interface (GUI) toolkit that includes a rich set
of widgets.
It includes package to create GUI components
for your Java applications
It is platform independent.

Java Swings
 Swing API is a set of extensible GUI
Components to ease the developer's life to
create JAVA based Front End/GUI Applications.
Swing component follows a Model-View-
Controller architecture to fulfill the following
criteria.
 A single API is to be sufficient to support
multiple look and feel.

• Unlike AWT, Java Swing provides platform-
independent and lightweight components.
• The javax.swing package provides classes for java
swing API such as JButton, JTextField, JTextArea,
JRadioButton, JCheckbox, JMenu, JColorChooser
etc.
import javax.swing.*;
Java Swings

Java Swings- Features
Light Weight
Rich Controls - Swing provides a rich set of
advanced controls like Tree, TabbedPane, slider,
colorpicker, and table controls.
Highly Customizable - Swing controls can be
customized in a very easy way as visual
apperance is independent of internal
representation.
Pluggable look-and-feel - SWING based GUI
Application look and feel can be changed at run-
time, based on available values.

Abstract Window Toolkit_Event Handling_python

Abstract Window Toolkit_Event Handling_python

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