Principles of OOP

CLASS Class is made of data and functions. OBJECTS Objects are basic run time entity in object oriented system. They represent a place, a bank account,  or person.  Objects are the instance of class or a variable of user defined data types. When you declare a class there is no memory for data, after creation of class memory is allocated for data and this process is called as instantiation. Each object has its own copy of instance variable of its class. It means any changes to the variable of one object have no…Read more

Introduction to HTML 103

Paragraphs and headings We're definitely making good progress! We've learned when and why we use HTML. We've also learned how to: a. Set up an HTML file with tags b. Title the webpage (in the <head>) c. Create paragraphs (in the <body> with <p> tags) The next step is to give our paragraphs headings using heading tags. Let's start with the <h1> tag. The content between this tag will be the biggest! Do it Yourself Create a new html file with Notepad++ and name it as test.html. Copy the code lines below and…Read more

Handling GUI Generated Events 3

Developing Event Listener:- In this section, you will learn about a design and implementation choices for implementing event listeners. Event Adapters:- It is a lot of work to implement all of the methods in each of the listener interfaces, particularly the MouseListener interface and WindowListener interface. For example, the MouseListener interface declares the following methods: public void mouseClicked(MouseEvent event) public void mouseEntered(MouseEvent event) public void mouseExited(MouseEvent event) public void mousePressed(MouseEvent event) public void mouseReleased(MouseEvent event) As a convenience, the java programming language provides adapter classes that implement each interface containing more than one…Read more
Introduction to HTML 102

Introduction to HTML 102

In our previous lesson we have learned how to create a HTML document using Notepad++. Today we will go a little further. We will learn the basic parts of a web-page i.e.: head, title, body and paragraph. Make the head Everything in our HTML file will go between the opening and closing tags. There are always two parts to the file: the head and body. Let’s focus on the head. a. It has an opening and a closing tag. b. The head includes important information about the webpage, such as its title. c.…Read more

Handling GUI Generated Events 2

GUI Behavior:- This section describes the event categories. Event Categories:- The general mechanism for receiving events from components has been described in the context of a single type of event. Many of the event classes reside in the java.awt.event package, but other exist in the API. For each category of events, an interface has to be implemented by the class objects that want to receive the events. That interface demands that one or more methods be defined as well. Those methods are called when particular events arise. The given below lists these categories…Read more

Handling GUI Generated Events 1

What is an Event? When the user performs an action at the user interface level (clicks a mouse or presses a key), this causes an event to be issued. Events are objects that describe what has happened. A number of different types of event classes exist to describe different categories of user action. When a user clicks a GUI button, an event object is created by the JVM and the button sends this event to the event handler for that button by calling the actionPerformed method. Event Sources:- An event source is the…Read more

Java GUI’s Using the Swing API 4

GUI Construction:- A Java technology GUI can be created using either of the following technique: Programming construction This technique uses code to create the GUI. This technique is useful for learning GUI construction. However, it is very laborious for use in production environments. Construction using a GUI builder tool This technique uses a GUI builder tool to create the GUI. The GUI developer uses a visual approach to drag and drop containers and components to a work area. The tool permits the positioning and resizing of containers and components using a pointer device…Read more

Java GUI’s Using the Swing API 3

Layout Manager:- A layout manager does determine the size and position of the components within a container. The alternative to using layout managers is absolute positioning by pixel coordinates. Absolute positioning is achieved through setting a containers layout property to null. Absolute positioning is not platform portable. Issues such as a size of fonts and screens ensure that a layout that is correct based on coordinates can potentially be unusable on other platforms. Unlike absolute positioning, layout managers have mechanisms to cope with the following situations: The resizing of the GUI by the…Read more

Java GUI’s Using the Swing API 2

Swing Packages:- The Swing API has a rich and convenient set of packages that makes it powerful and flexible. The given below lists each package name and the purpose of each package. 1.     javax.swing:- Provides a set of light weight components such as, JFrame, JButton, JCheckBox and much more. 2.     javax.swing.border:- Provides classes and interfaces for drawing specialized border such as line, etched, bevel, matte and more. 3.     javax.swing .event:- Provides support for events fired by Swing components. 4.     javax.swing.undo:- Allows developers to provide support for undo/redo in applications such as text editor.…Read more

Java GUI’s Using the Swing API 1

What are the Java Foundation Classes (JFC)? JFC, or Java Foundation Classes, is a set of Graphical User Interface (GUI) support packages that are available as part of the java SE platform and which became core application program interfaces (APIs) in JDK 1.2. As a result of this, some of the boundaries between JFC and core JDK have become blurred, but in this, JFC includes the following features: The Swing component set: - The Swing is an enhanced component set that provides replacement components for those in the original AWT and a number…Read more