MouseListener
This type of mouse listener is for events which typically don't happen very often
-- a mouse button is pressed, released, or the mouse enters or leaves the
area of the component with a listener. Here are the actions that a MouseListener
catches.
| press | one of the mouse buttons is pressed. |
| release | one of the mouse buttons is released. |
| click | a mouse button was pressed and released without moving the mouse.
This is perhaps the most commonly used. |
| enter | mouse cursor enters the component. Often used to change cursor. |
| exit | mouse cursor exits the component. Often used to restore cursor. |
To listen for these events you will use
addMouseListener.
MouseListener Interface
To implement a MouseListener interface, you must define the following methods.
You can copy these definitions into your program and only make a meaningful
body for those methods that are of interest.
public void mousePressed(MouseEvent e) {}
public void mouseReleased(MouseEvent e) {}
public void mouseClicked(MouseEvent e) {}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
| This method is called |
When the user does this action |
mouseClicked |
A click is the result of a press and a release.
This is probably the most common method to write. |
mousePressed |
A mouse button is pressed (any of three possible mouse buttons) |
mouseReleased |
A mouse button is released. |
mouseEntered |
The mouse cursor enters a component.
You might write this to change the cursor. |
mouseExited |
The mouse cursor leaves a component.
You might write this to restore the cursor. |
To Get the Mouse Coordinates
All coordinates are relative to the upper left corner
of the component with the mouse listener. Use the
following MouseEvent methods to get x and y coordinates
of where the mouse event occurred.
int getX() // returns the x coordinate of the event.int getY() // returns the y coordinate of the event.
To Check for Double Clicks
Use the following MouseEvent method to get a count of the number
of clicks.
int getClickCount() // number of mouse clicks