Can actionPerformed return a value?
The actionPerformed method is a void type, so it cannot return values.
What does actionPerformed do in Java?
The Action Listener API
| Method | Purpose |
|---|---|
| actionPerformed(actionEvent) | Called just after the user performs an action. |
What is actionPerformed ActionEvent E in Java?
The actionPerformed() method is invoked automatically whenever you click on the registered component. public abstract void actionPerformed(ActionEvent e);
How does ActionListener work in Java?
To determine where the user clicked on the screen, Java provides an interface called “ActionListener” through which we determine where the user clicked and generates an event to perform several tasks, like calculation, print a value, print a specific character, etcetera using a button.
What events do JButton generate?
JButton. A JButton object draws itself and processes mouse, keyboard, and focus events on its own. You only hear from the JButton when the user triggers it by clicking on it or pressing the space bar while the button has the input focus.
What does GetText do in Java?
GetText returns the text from the single-line text field. It returns only the first line of a multi-line text field.
What is the return type of getSource method?
The getSource method is used in the actionPerformed method to determine which button was clicked….Java For Dummies Quick Reference by.
| Method | Description |
|---|---|
| object getSource() | Returns the object on which the event occurred |
How do action listeners work in Java?
What is ActionListener interface 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.
How do you add onclick events in Java?
After adding the components to the interface, I’m adding action listeners to every component so that when text area button is clicked, focus changes to text area and when text field button is clicked, focus changes to text field. Don’t use TextArea , that is an AWT component. Use a JTextArea .
What is the return type of getText ()?
it actually returns Editable and not CharSequence but you can store it in a String variable by calling toString() on it.
What is the return value type of the function getText ()?
What is e getSource () 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.
What is the return type of the method getID () defined in AWTEvent class?
Explanation : : Int is the return type of the method getID() in AWTEvent Class.
How does an event listener 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. Have a look at the AWT/Swing event model in Java for example.
Why is ActionListener an interface?
Interface ActionListener 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.