This section contains the detail about the Event Classes in java Swing.
Java has a number of classes that describe different categories of events. The following figure shows the hierarchy of a Java event class :
The Action Event class
? ActionEvent is generated by an AWT component, such as a button, when a
component-specific action is performed.
? The action event is generated when a button is pressed, a list item is double-clicked, or a menu item is selected.
? The following syntax shows the declaration of the constructor of the ActionEvent class is:
public ActionEvent(Object source, int id, String command)
? The main methods included in the Action Event class are:
? String getActionCommand
The MouseEvent class
? The MouseEvent class extends the java.awt.event.InputEvent class.
? The mouse event indicates that a mouse action has occurred on a component.
? The mouse events include:
? Pressing a mouse button
? Releasing a mouse button
? Clicking a mouse button
? Entering of mouse in a component area
? Exiting of mouse from a component area
? The mouse event class defines some integer constants that can be used to identify several types of mouse events.
Given below the various integer constants of the Event class :
|MOUSE_CLICKED||Identifies the event of mouse clicking.|
|MOUSE_DRAGGED||Identifies the event of dragging of
|MOUSE_MOVED||Identifies the event of mouse moving.|
|MOUSE_PRESSED||Identifies the event of mouse pressing.|
|MOUSE_RELEASED||Identifies the event of mouse
|MOUSE_ENTERED||Identifies the event of mouse
entering an AWT component.
|MOUSE_EXITED||Identifies the event of mouse exiting
an AWT component.
Given below Various methods of the MouseEvent class :
|public int getX()||Returns the horizontal x coordinate of
the mouse position relative to a source
|public int getY()||Returns the vertical y coordinate of the
mouse position relative to a source
|public point getPoint()||Returns the Point object. The Point
object contains the x and y coordinates
of the mouse position relative to a
|public void translatePoint(int x, int y)||Translates the coordinates of a mouse
event to a new position by adding x and
|public int getClickCount()||Returns the number of mouse clicks
associated with an event.