In this example we shall show you how to create a MouseListener example using the Google Web Toolkit, that is an open source set of tools that allows web developers to create and maintain complex JavaScript front-end applications in Java. The MouseListener is an Event listener interface for mouse events.To create a MouseListener we have performed the following steps:
- The
MouseListenerExampleclass implements thecom.google.gwt.core.client.EntryPointinterface to allow the class to act as a module entry point. It overrides itsonModuleLoad()method. - Create a Label widget.
- Attach a new MouseListener to the Label. Implement the MouseListener methods,
onMouseEnter(Widget sender),onMouseLeave(Widget sender),onMouseDown(Widget sender, int x, int y),onMouseMove(Widget sender, int x, int y)andonMouseUp(Widget sender, int x, int y)methods. - Add the Label to the Label to the
RootPanel, that is the panel to which all other widgets must ultimately be added,
as described in the code snippet below.
package com.javacodegeeks.snippets.enterprise;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.MouseListener;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.Widget;
public class MouseListenerExample implements EntryPoint {
@Override
public void onModuleLoad() {
// Create Label widget
final Label label = new Label("Play with me");
// Attach mouse listener to label
label.addMouseListener(new MouseListener() {
// Implement the onMouseEnter method
@Override
public void onMouseEnter(Widget sender) {
label.setText("Mouse cursor just entered the Label widget");
}
// Implement the onMouseLeave method
@Override
public void onMouseLeave(Widget sender) {
label.setText("Mouse cursor just left from the Label widget");
}
// Implement the onMouseDown method
@Override
public void onMouseDown(Widget sender, int x, int y) {
label.setText("You clicked me!");
}
// onMouseMove method (does nothing)
@Override
public void onMouseMove(Widget sender, int x, int y) {
// do nothing
}
// onMouseUp method (does nothing)
@Override
public void onMouseUp(Widget sender, int x, int y) {
// do nothing
}
});
// Add label widget to Root Panel
RootPanel.get().add(label);
}
}
This was an example of how to create a MouseListener example using the Google Web Toolkit.
