Question

What method controls the visibility of swing components? a. visible () b. setVisible () c. show0 d. None of the above

Short answer

Option b (setVisible ()) is correct.

Step-by-step solution

Understand the Question

The question asks which method is used to control the visibility of Swing components in Java.

Review Options

Examine the provided options:a. visible ()b. setVisible ()c. show0d. None of the above

Recall Java Swing Methods

Recall that in Java's Swing library, the method used to change the visibility of a component like a JFrame, JPanel, etc., is `setVisible(boolean b)`.

Compare with Options

Compare the method `setVisible(boolean b)` with the given choices:- Option a is `visible ()`, which is not the correct method.- Option b is `setVisible ()`, which is correct.- Option c is `show0`, which is incorrect.- Option d is `None of the above`, which is incorrect since option b is correct.

Conclude the Answer

Based on the comparison, option b (`setVisible ()`) is the correct method to control the visibility of Swing components.

Key concepts

Java Swing Methods

Java Swing is a part of Java’s standard library that provides a rich set of GUI (Graphical User Interface) components. These components allow developers to create windows, buttons, text fields, and more. The Swing library is built on top of AWT (Abstract Window Toolkit) and is part of the javax.swing package. Swing components include JFrame, JPanel, JButton, JTextField, among others. Each of these components possesses various methods to manage their properties such as size, visibility, and behavior.
One of the main advantages of using Swing is that it is platform-independent. This means that a Swing application will look the same on any platform, whether it be Windows, macOS, or Linux.
Some common methods in Java Swing include:

• setSize(int width, int height): Sets the size of the component.
• setLocation(int x, int y): Sets the position of the component.
• setVisible(boolean b): Controls the visibility of the component.

setVisible(boolean)

The method `setVisible(boolean b)` is crucial in Java Swing for controlling the visibility of components. This method belongs to the java.awt.Component class, from which many Swing components inherit.
When you call `setVisible(true)`, the component is shown on the screen. Conversely, `setVisible(false)` will hide the component.
Here's an example:
JFrame frame = new JFrame('My Frame');
frame.setSize(300, 200);
frame.setVisible(true);
In this example, a new JFrame is created and its size is set to 300 pixels wide and 200 pixels tall. The `setVisible(true)` call ensures that the frame is displayed on the screen.
It is important to note that if you want to make a number of changes to a component that affect its appearance, it is often a good idea to set it to invisible (`setVisible(false)`), make the changes, and then set it back to visible (`setVisible(true)`), to avoid unnecessary repaints and flickers.

Java GUI Programming

Java GUI programming involves the creation and manipulation of graphical components to build user interfaces. Swing, as part of Java's GUI toolkit, is one of the most common libraries used for this purpose.
Creating a GUI in Java generally involves these steps:

• Define the main frame/window using `JFrame`.
• Add components like buttons, text fields, and panels to the frame.
• Set properties for each component such as size, location, and visibility.
• Implement event listeners to handle user actions like button clicks.

An example of a simple Java GUI application is:
public class MyGuiApp {
public static void main(String[] args) {
JFrame frame = new JFrame('Hello World');
frame.setSize(400, 300);
JButton button = new JButton('Click Me');
frame.add(button);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
This code creates a window with a button labeled 'Click Me'. When the application runs, the window will appear on the screen because of the `frame.setVisible(true);` call.
Java GUI programming enables you to create interactive and user-friendly applications that can run on any platform that supports Java.