Java Front end components like buttons etc explained in simple terms.
After having the basic idea of GUI, let us know how many Java AWT Components classes exist with java.awt package. This knowledge is essential to go further in the tutorial. As you can observe from the above hierarchy, Component is the super class of all Java components and is declared as abstract. That is, we …
After knowing what a component is, let us go to the list of containers Java supports. For this, the container hierarchy is separated from the earlier component hierarchy and displayed here. Infact, the Container is a component as it is a subclass of Component class. It can use all the methods of Component class and …
The java.awt package comes with many GUI components of which Button is the most important and most frequently used. A button functionality (what for it is) can be known by its label like OK or Cancel etc. A mouse click on the button generates an action. Following is the class signature public class Button extends …
The GUI components can be placed in a frame or an applet (as both are containers). We have seen many programs with frame and now let us write an applet with GUI, say button. While developing applet GUI, the class should extend Applet instead of Frame. The constructor is replaced with init() method. In the …
After validating user name and password using TextField in an application (application extends frame), let us rewrite the same program using applets but with a different functionality. We take two numbers from the user and display the sum of two numbers. The following program comes with 3 text fields. In two text fields, user enters …
After learning GUI creation through 8 steps, for more command over button event handling, apart this one, another two programs are given – Changing Button Label and Making Button Enabled. Example on Java make Button Invisible In the following program, three buttons are created with labels Red, Green and Blue. When Red button is clicked, …
After learning GUI creation through 8 steps, for more command over button event handling, apart this one, another two programs are given – Changing Button Label and Making Button Invisible. In the following program, three buttons are created with labels Red, Green and Blue. When Red button is clicked, the Blue button is enabled and …
After learning the GUI creation through 8 steps, for more command over button event handling, apart this one, another two programs are given – Making Button Enabled and Making Button Invisible. In this program, the same button label toggles between Bharath and India. When Bharath is clicked, the button label changes to India and when …
Label component displays text just like a drawString(). The difference is Label gets the status of a component so that it can be added in position format using layout manager. Label displays text in one line only. User cannot edit the text of the label. It is meant only for the programmer to display some …
After Button, the most used AWT component is TextField. TextField is useful to take input from the user and also to display output to the user by the programmer. User can write and edit the text in the TextField. Programmatically, the TextField can be made non-editable. Pressing Enter key generates ActionEvent and can be handled …
1. What is Radio button? Infact, there is no radio button class in Java. Radio buttons are nothing but checkboxes only but grouped as one unit. 2. What the advantage of grouping checkboxes? Once grouped, in the group if one checkbox is selected, the other gets automatically deselected. This is the only advantage. Sometimes, it …
To develop user friendly and good look environment, the layout of the components in a container is very important to the programmer like the selection of colors and fonts for graphics. The user should feel free and comfortable to stay some time in GUI. To give attractive graphical user interface design, the AWT package comes …
The paint() method is called by the JVM implicitly in two circumstances. One is when the first time frame is created and displayed. The other is when the frame is resized (by dragging the frame border with mouse) by the user. If the programmer would like to call the paint() method in the middle of …
Java AWT Panels play a very important role in layout management. Panels in combination with layout managers render the desired layout to the programmer. Following hierarchy gives the place of Panel in AWT API. java.lang.Object –> java.awt.Component –> java.awt.Container –> java.awt.Panel –> java.applet.Applet Properties of Java AWT Panels As you can see from the hierarchy, …
This is second program on TextField, first being User Name Password Validation (applet version is also available). The methods like setColumns(), setText() and setFont(), getColumns() and getText() are used to set and get the properties. Example on using Java TextField Methods import java.awt.*; public class TextFieldProperties extends Frame { TextField tf1, tf2, tf3; public TextFieldProperties() …
Checkbox is another Java component used by the programmer when the user is left with two options only – either yes or no, that is, want or don't want. The check box when selected by the user, returns true and when deselected returns false. The checkbox toggles between two states – true or false. The …
Canvas, in general sense, is a cloth where a painter can put some painting. But for us, Canvas is a class from java.awt package on which a programmer can draw some shapes or display images. A mouse click or a keyboard key press on the canvas can generate events and these events can be converted …
The scrollbar scrolls through a range of integer values. It is a very convenient component to take a value from the user within a range of values. Scrollbar have two orientations: Vertical or Horizontal. Scrollbar can be set with maximum and minimum values within which the scrollbar moves. The scroll bar may be given an …
Radio buttons give a more user friendly environment when the user has to select only one option among many. There is no radio button class in java.awt package. Radio buttons are a group of checkboxes grouped as one unit. In the unit, if another radio button is selected, the earlier gets automatically deselected. Because radio …
List permits the selection of multiple items (Choice allows single selection). Programmer prefers List when checkboxes are many to display (in case of Choice, when radio buttons are many to display). List adds a scrollbar with which items can be scrolled and seen. List can be designed for single selection or multiple selection (Java AWT …
