Can you have multiple action listeners Java?
6 Answers. You can either use ActionEvent. getSource() to decide the source and act accordingly or you can define different ActionListeners for each of them. You just need to create new instance of the ActionListener each time.
How do you add a listener to a button in Java?
Java ActionListener Example: On Button click
- import java.awt.*;
- import java.awt.event.*;
- //1st step.
- public class ActionListenerExample implements ActionListener{
- public static void main(String[] args) {
- Frame f=new Frame(“ActionListener Example”);
- final TextField tf=new TextField();
- tf.setBounds(50,50, 150,20);
How do I get more than one ActionListener?
All you have to do to work with multiple listeners is: Create a class that extends JFrame and implements ActionListener . Create an number of these JFrames and put them in an array. This array could easily hold any class as long as it implements the ActionListener interface.
What are action listeners in Java?
ActionListener in Java is a class that is responsible for handling all action events such as when the user clicks on a component. Mostly, action listeners are used for JButtons. An ActionListener can be used by the implements keyword to the class definition.
Can a button have multiple action listeners?
What is e getSource method in Java?
Description. object getSource() Returns the object on which the event occurred. You can use the getSource method to determine which component sourced the event when the listener is registered as an event listener with more than one component.
How do you make a button perform an action in Java?
In short, to set action command for JButton one should follow these steps:
- Create a class that extends JFrame and implements ActionListener .
- Create a new JButton .
- Use JButton. addActionListener to add a specific ActionListener to this component.
- Use JButton.
- Override actionPerformed method and use ActionEvent.
What are action listeners?
You implement an action listener to define what should be done when an user performs certain operation. 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.
How do listeners work in Java?
An event listener in Java is designed to process some kind of event — it “listens” for an event, such as a user’s mouse click or a key press, and then it responds accordingly. An event listener must be connected to an event object that defines the event.
What is the purpose of a listener in Java?
An event listener in Java is designed to process some kind of event — it “listens” for an event, such as a user’s mouse click or a key press, and then it responds accordingly. An event listener must be connected to an event object that defines the event.
Is ActionListener a thread in Java?
No, an action listener is an interface. You can implement that interface by defining what its actionPerformed()method does (assuming you refer to this ActionListener). That method is going to run in the thread that calls it. So if you call it from one of your threads, it will run in that thread.
What is listener in Java?
Listener is a common form of implementing the observer design patter in Java. This technique is also referred to as the callback, which is a term coming from the world of procedural languages.