What is the difference between MouseEvent, ActionEvent and Event in JavaFX?

Event is the superclass of all event types.

Examples of event types:

• KeyEvents that are generated when a key is pressed.
• MouseEvents that are generated by mouse interaction, like moving or clicking a button.
• There are many more.

Events should not be generated by the JavaFX system alone. You can emit and consume your own custom events if you like, but generally most events are generated by the JavaFX system.

An ActionEvent is a kind of event that often makes it easier to code and react to something being triggered.

Often, multiple events are generated for one action. For example, if you click on a button with your mouse, you can get MOUSE_PRESSED , MOUSE_RELEASED, and MOUSE_CLICKED events in addition to ActionEvent.

If you want to respond to a button activation, you can listen for the MOUSE_CLICKED event, however this is not recommended. This is because there are other ways to activate the button, or the button might be disabled, in which case you do not want to take action on it. If this is the default button, the ENTER key can trigger the button, or the user can activate the button by pressing SPACE when they are focused on the button. When a button is activated by the keyboard, no associated mouse event occurs, so listening for mouse events to activate the mouse is not recommended. Usually, you just want to know what the button was activated, not what caused it, and you don't want to control all types of events yourself, what could lead to activation and under what conditions the activation should happen when the event is triggered.

JavaFX provides an ActionEvent that will be emitted whenever a button is activated, regardless of the method that was used to activate it. This makes the code a lot easier for you since all you have to write is button.setOnAction(event -> handleButtonAction());

.

ActionEvent is also used in many places where it is not practical or necessary to create a specific type of event, such as animating a KeyFrame when a keyframe is activated. Therefore, ActionEvents are not just used to handle button events, but can be used in many places.