In this example we shall show you how to create a CheckBox 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. To create a CheckBox example one should perform the following steps:
- The
CheckBoxExampleclass implements thecom.google.gwt.core.client.EntryPointinterface to allow the class to act as a module entry point. It overrides itsonModuleLoad()method. - Create a new VerticalPanel.
- Create a few instances of CheckBox.
- Add a ClickHandler to the check box and override its
onClick(ClickEvent event)method to handle the click events. - Add the check box to the VerticalPanel.
- Add the VerticalPanel 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.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 CheckBoxExample implements EntryPoint {
final String[] Items = { "Item0", "Item1", "Item2", "Item3", "Item4", "Item5" };
@Override
public void onModuleLoad() {
// Create new Instance of vertical panel to align the check boxes
VerticalPanel vp = new VerticalPanel();
// Create i Instances of CheckBox()
for (int i = 0; i < Items.length; i++) {
// Add Item
final CheckBox checkBox = new CheckBox(Items[i]);
// Add ClickHandler
checkBox.addClickHandler(new ClickHandler(){
@Override
public void onClick(ClickEvent event) {
check(checkBox);
}
});
//Set some checkBoxes disabled by default
if (i > 3)
checkBox.setEnabled(false);
//Add checkBox to Vertical Panel
vp.add(checkBox);
}
//Add Vertical Panel to Root Panel
RootPanel.get().add(vp);
}
// Method that notifies the user whether a checkBox is checked or not
public void check(CheckBox checkBox){
boolean checked = checkBox.getValue();
Window.alert(checkBox.getText() + " is " + (checked ? "" : "not ") + "checked");
}
}
This was an example of how to create a CheckBox example using the Google Web Toolkit.
