Which checkbox was clicked?

[Laurence Turpin]

Hello,

I'm using GWT 2.4 on Windows 7.
I am writing a program with 3 checkboxes
marked as Red Green and Blue.
Inside the onClick() method I wish to identify which checkbox was clicked.
The program I have at the moment is shown below:

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.CheckBox;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.VerticalPanel;


public class GWTEventsCheckBox2 implements EntryPoint, ClickHandler {

  public void onModuleLoad() {
    VerticalPanel verticalPanel = new VerticalPanel();
    CheckBox chkRedCheckBox = new CheckBox("red");
    chkRedCheckBox.addClickHandler(this);
    CheckBox chkGreenCheckBox = new CheckBox("Green");
    chkGreenCheckBox.addClickHandler(this);
    CheckBox chkBlueCheckBox = new CheckBox("Blue");
    chkBlueCheckBox.addClickHandler(this);
    verticalPanel.add(chkRedCheckBox);
    verticalPanel.add(chkGreenCheckBox);
    verticalPanel.add(chkBlueCheckBox);
    RootPanel.get().add(verticalPanel);
  }
  

  @Override
  public void onClick(ClickEvent event) {
    Window.alert("Want to put the name of checkbox that was clicked here");
    
  }
}

Inside the Window.alert() method I wish to put the checkbox that was clicked, but do not know how to identify it.
It can be done with 3 different handler classes.
One for each checkbox but that does not seem to be an efficient way of doing it.
Has anyone any ideas?

[Maneesh Godbole]

ClickEvent has a getSource() method which returns the event origin. In your case it will be a CheckBox. So, if you use this method you will need to type cast it to a CheckBox. Once you get the CheckBox, you can use the getText to see which check box was clicked.

[Laurence Turpin]

Thank you Manesh Godbole for your reply which has solved my problem.
Below is the corrected program.

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.CheckBox;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.VerticalPanel;


public class GWTEventsCheckBox2 implements EntryPoint, ClickHandler {
  private CheckBox chkRedCheckBox = null;
  private CheckBox chkGreenCheckBox = null;
  private CheckBox chkBlueCheckBox = null;

  public void onModuleLoad() {
    VerticalPanel verticalPanel = new VerticalPanel();
    chkRedCheckBox = new CheckBox("red");
    chkRedCheckBox.addClickHandler(this);
    chkGreenCheckBox = new CheckBox("Green");
    chkGreenCheckBox.addClickHandler(this);
    chkBlueCheckBox = new CheckBox("Blue");
    chkBlueCheckBox.addClickHandler(this);
    verticalPanel.add(chkRedCheckBox);
    verticalPanel.add(chkGreenCheckBox);
    verticalPanel.add(chkBlueCheckBox);
    RootPanel.get().add(verticalPanel);
  }
  
  @Override
  public void onClick(ClickEvent event) {
    Window.alert(((CheckBox)event.getSource()).getText());
    
  }
}