Docsity
Docsity

Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity


Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan


Guidelines and tips
Guidelines and tips

GUI Components-Java Network Programming-Lecture Slides, Slides of Java Programming

This lecture is delivered by Prem Vikas at Jaypee Institute of Information Technology University for discussing following points of Java Network Programming: Components, Hierarchy, GUI, Classes, Properties, JBuilder7, AWT, Components, Event, Handling

Typology: Slides

2011/2012

Uploaded on 07/03/2012

aapti
aapti 🇮🇳

4.6

(28)

82 documents

1 / 24

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
Java Programming
Day-04
Docsity.com
pf3
pf4
pf5
pf8
pf9
pfa
pfd
pfe
pff
pf12
pf13
pf14
pf15
pf16
pf17
pf18

Partial preview of the text

Download GUI Components-Java Network Programming-Lecture Slides and more Slides Java Programming in PDF only on Docsity!

Java Programming

Day-

Outline

  • Applets Once again
  • GUI-Components
  • Components hierarchy
  • Packages
  • The Java AWT Package
  • Exploring Component Classes
  • Creating and Using Components
  • Exploring Components Properties
  • Using JBuilder7 design tool

Packages

  • Packages

 java.awt  jvax.swings

  • java.awt pacakge

 Abstract Windowing Kit  GUI-Components are drawn according to the underlying windowing system  Initial set of Components developed  AWT Components  Buttons  Text Fields  Labels  Text Areas  Check Boxes  Menus  Radio Buttons  Canvases  Lists  Scroll Panes  Choices

First Button

  • Two simple steps

 Create a Button

 Add button to the applet

 Don’t Forget to import the awt package.

  • Step-

public Button firstButton = new Button(“ Click It ”);

  • Step-

add(firstButton); Complete Program

import java.awt.*;

import java.applet.*;

public class ButtonApplet extends Applet{ public Button firstButton = new Button(“Click It public void init( ){ add(firstButton);

} }

Button applet output

  • Button Applet

Adding few more buttons

import java.awt.*;

import java.applet.*;

public class ButtonApplet extends Applet{

//creating the button component

public Button firstButton = new Button(“One”);

public Button secondButton = new Button(“Two”);

public Button thirdButton = new Button(“Threet”);

public void init( ){

//adding to the applet

add(firstButton); add(secondButton); add(thirdButton); }

}

Layout Managers

  • How your components should be organized

 Layout Managers draw place your components at relative positions

 Absolute position can cause problems

 Necessary for application intended for different platforms

 Layout Managers are classes

 AWT Layout Managers

 Flow Layout  GridLayout  Border Layout  CardLayout  GridBagLayout

 So how did the previous applet worked

 The default layout manager

Using Layout managers

  • Few Simple Steps

 Prepare your container

 Create the container class e.g. applet  Set layout

 Create instance of a Components

 Set Initial conditions e.g. titles, x y position, size etc..

 Add component to the container

  • Setting layout

 The setLayout method

setLayout(Object of a Layout Class)

 Inherited from Applet class

Flow Layout…cont..

  • Example-

 Using Flow Layout constructor 1

import java.awt.; import java.applet.;

public class flowLayoutTest extends Applet{

public FlowLayout myFlowLayout=new FlowLayout(); Button B=new Button(“Click It”);

public void init(){ setLayout(myFlowLayout);

add(B); } }

Flow layout cont..

  • Example-

 Using a different constructor

import java.awt.; import java.applet.;

public class flowLayoutTest extends Applet{

public FlowLayout myFlowLayout=newFlowLayout(FlowLayout.Right);

Button B=new Button(“Click It”);

public void init(){ setLayout(myFlowLayout); add(B); } }

Using Labels

  • String for descriptions or decoration
  • Constructors

 public Label()

 public Label( String text)

 public Label( String text, int alignment)

  • Alignments

 Label.LEFT

 Label.RIGHT

  • Important methods

 coid setText(String text) //to set the label text

 String getText() // to get the label text

 void setAlignment(int Alignment) //set alignment of the label

 public int getAlignment() // get alignment of the label

Labels..

  • Example-

 A label for a button import java.awt.; import java.applet.;

public class flowLayoutTest extends Applet{

public FlowLayout myFlowLayout= newFlowLayout((FlowLayout.Right );

Label label_save=new Label( “Save”); Button B=new Button(“Save”);

public void init(){

setLayout(myFlowLayout); add(label_save); add(B); }}

Using Text Areas

  • Multi-line input component
  • Constructors

 public TextArea()

 Creates an empty text area with default size (9 rows,47 columns)

 public TextArea(Strig initialText)

 Creates a text area and displays the given text

 public TextArea(int numrows,int numcolumns)

 Creates a text area according to the given number of rows and coumns

 public TextArea(String initialText,int numRows,int numcolumns)

  • Important methods

 pubic void appendText(String text)

 Adds text at the end of the current text in the text area

 public void insert(String text,int position)

 Adds text at specified character position

 public void replaceText(String text,int start,int end)

Event Handling

  • Events are raised when

 The state of a component is changed

 A button click  Clicking a check box

 User performs some action on a component

 Writing text to a field  Clicking on the applet surface

  • Handling events

 Interfaces

 action() method

 Depricated method previously used for handling events  Cannot deal all sorts of events  Syntax public boolean action(Event evnt, Object obj){ -------code to perform some actions----------- }