What is an action event in Java?
An action event occurs, whenever an action is performed by the user. Examples: When the user clicks a button, chooses a menu item, presses Enter in a text field. The result is that an actionPerformed message is sent to all action listeners that are registered on the relevant component.
What is the use of getSource in Java?
The getSource method is used in the actionPerformed method to determine which button was clicked.
What is a event listener?
An event listener is a procedure or function in a computer program that waits for an event to occur. Examples of an event are the user clicking or moving the mouse, pressing a key on the keyboard, disk I/O, network activity, or an internal timer or interrupt.
What are the types of event listeners?
Add Event Listener DOM Event Types
- Mouse Events: click, dblclick, mousedown, mouseup, contextmenu, mouseout, mousewheel, mouseover.
- Touch Events: touchstart, touchend, touchmove, touchcancel.
- Keyboard Events: keydown, keyup, keypress.
- Form Events: focus, blur, change, submit.
What are the different kinds of event listeners in Java?
The Event listener represent the interfaces responsible to handle events. Java provides us various Event listener classes but we will discuss those which are more frequently used. Every method of an event listener method has a single argument as an object which is subclass of EventObject class.
What is action listener interface in Java?
The listener interface for receiving action events. The class that is interested in processing an action event implements this interface, and the object created with that class is registered with a component, using the component’s addActionListener method.
What does event getSource () do?
event. getSource() helps you determine which component fired an event. Let’s say you have several buttons that reuse the same onclick handler. To retrieve the name of the button that fired the event, use event.
What is event listener used for?
How do event listeners work?
Often an event listener is registered with the object that generates the event. When the event occurs, the object iterates through all listeners registered with it informing them of the event.
Why do we use event listener?
Event listeners are among the most frequently used JavaScript structures in web design. They allow us to add interactive functionality to HTML elements by “listening” to different events that take place on the page, such as when the user clicks a button, presses a key, or when an element loads.
What is setLayout in Java?
The setLayout(…) method allows you to set the layout of the container, often a JPanel, to say FlowLayout, BorderLayout, GridLayout, null layout, or whatever layout desired. The layout manager helps lay out the components held by this container.