GWT-Wizard Sample Code

README.md

Sample code from a page of the Fresno Pacific University Vehicle Reservation Wizard.

RequesterInfoPage.java defines the business logic for the page, as well as the Display interface for the UI; RequesterInfoPageView.java implements the Display interface. Notice that the view extends LazyComposite to lazily create the view on demand (the first time the page is shown).

RequesterInfoPage.java

package edu.fresno.gwt.vehiclereservation.client.page;

import java.util.ArrayList;
import java.util.List;

import net.binarymuse.gwt.client.ui.wizard.WizardPage;
import net.binarymuse.gwt.client.ui.wizard.event.NavigationEvent;

import com.allen_sauer.gwt.log.client.Log;
import com.google.gwt.event.dom.client.KeyPressHandler;
import com.google.gwt.user.client.Command;
import com.google.gwt.user.client.DeferredCommand;
import com.google.gwt.user.client.ui.HasHTML;
import com.google.gwt.user.client.ui.HasValue;
import com.google.gwt.user.client.ui.Widget;

import edu.fresno.gwt.vehiclereservation.shared.VehicleReservationContext;

public class RequesterInfoPage extends WizardPage<VehicleReservationContext> {

    // The Display interface here defines methods that the
    // view for this page must define. The presenter (this object)
    // uses these methods to manipulate the view, without knowing
    // the details of exactly how the view is implemented.
    public interface Display {
        // HasX methods for getting fields that present a value
        HasValue<String> getRequesterNameValue();
        HasValue<String> getRequesterEmailValue();
        HasValue<String> getRequesterPhoneValue();
        HasValue<String> getDepartmentBilledValue();
        HasValue<String> getAccountNumberValue();

        HasHTML getErrorHTML();

        // Methods to implement various view functionality
        void addKeyPressHandlers(KeyPressHandler handler);
        void focusFirstBlankField();
        void showErrors(List<String> errors);

        // asWidget() allows the page to be added to the wizard
        Widget asWidget();
    }

    public final static PageID PAGEID = new PageID();
    public final Display view;

    // Not technically good MVP practice here; ideally, we
    // would use Dependency Injection to inject the view.
    public RequesterInfoPage() {
        view = new RequesterInfoPageView();
    }

    @Override
    public PageID getPageID() {
        return PAGEID;
    }

    @Override
    public Widget asWidget() {
        return view.asWidget();
    }

    @Override
    public String getTitle() {
        return "Requester Information";
    }

    // Fires only the first time the page is shown (before it is actually
    // shown). Gets any values from the context that may have been set
    // from previous pages (e.g. the login page) and sets the data
    // in the view.
    //
    // Also does some other basic view setup, such as injecting a
    // KeyPressHandler into the fields (so the user can go next by pressing
    // the enter key) and setting the focus to the first blank field (using
    // a DeferredCommand so that the code executes once the other events
    // finish.)
    @Override
    public void beforeFirstShow() {
        if(getContext().authFullname != null)
            view.getRequesterNameValue().setValue(getContext().authFullname);
        if(getContext().authEmail != null)
            view.getRequesterEmailValue().setValue(getContext().authEmail);

        view.addKeyPressHandlers(getWizard().getView().getHandlerFactory().getEnterKeyNextHandler());

        DeferredCommand.addCommand(new Command() {
            @Override
            public void execute() {
                view.focusFirstBlankField();
            }
        });
    }

    @Override
    public void beforeShow() {
        view.showErrors(null);
    }

    // Commits the data to the context when moving to the next page
    // (assuming the data validates).
    @Override
    public void beforeNext(NavigationEvent event) {
        if(!validate())
            event.cancel();

        getContext().requesterName = view.getRequesterNameValue().getValue();
        getContext().requesterEmail = view.getRequesterEmailValue().getValue();
        getContext().requesterPhone = view.getRequesterPhoneValue().getValue();
        getContext().departmentName = view.getDepartmentBilledValue().getValue();
        getContext().accountNumber = view.getAccountNumberValue().getValue();
    }

    @Override
    public void afterNext() {
        Log.debug("RequesterInfoPage afterNext()");
        Log.debug(context.toString());
    }

    public boolean validate() {
        List<String> errors = new ArrayList<String>();
        if(view.getRequesterNameValue().getValue().isEmpty())
            errors.add("You must provide your name.");
        if(view.getRequesterEmailValue().getValue().isEmpty())
            errors.add("You must provide your email address.");
        if(view.getRequesterPhoneValue().getValue().isEmpty())
            errors.add("You must provide your phone number.");
        if(view.getDepartmentBilledValue().getValue().isEmpty())
            errors.add("You must specify the department to be billed.");
        if(view.getAccountNumberValue().getValue().isEmpty())
            errors.add("You must specify the account number of the department to be billed.");


        if(errors.size() == 0) {
            view.showErrors(null);
            return true;
        } else {
            view.showErrors(errors);
            return false;
        }
    }

}

RequesterInfoPageView.java

package edu.fresno.gwt.vehiclereservation.client.page;

import java.util.Iterator;
import java.util.List;

import net.binarymuse.gwt.client.ui.wizard.view.LazyComposite;

import com.google.gwt.event.dom.client.KeyPressHandler;
import com.google.gwt.user.client.ui.FlowPanel;
import com.google.gwt.user.client.ui.Grid;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.HasHTML;
import com.google.gwt.user.client.ui.HasValue;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.TextBox;
import com.google.gwt.user.client.ui.Widget;

// View extends LazyComposite and doesn't use initWidget()--this allows
// the wizard to initialize the view only when it's ready to be displayed
// for the first time.
public class RequesterInfoPageView extends LazyComposite implements RequesterInfoPage.Display {

    private FlowPanel panel;
    private Grid grid;
    private TextBox requesterName;
    private TextBox requesterEmail;
    private TextBox requesterPhone;
    private TextBox departmentBilled;
    private TextBox accountNumber;
    private HTML errorHTML;

    public RequesterInfoPageView() {
        requesterName = new TextBox();
        requesterEmail = new TextBox();
        requesterPhone = new TextBox();
        departmentBilled = new TextBox();
        accountNumber = new TextBox();
        errorHTML = new HTML();

        requesterName.setWidth("200px");
        requesterEmail.setWidth("200px");
        requesterPhone.setWidth("200px");
        departmentBilled.setWidth("200px");
        accountNumber.setWidth("200px");
        errorHTML.addStyleDependentName("error");
    }

    @Override
    public Widget createWidget() {
        panel = new FlowPanel();

        grid = new Grid(5, 2);

        grid.setWidget(0, 0, new Label("Requester Name:"));
        grid.setWidget(0, 1, requesterName);
        grid.setWidget(1, 0, new Label("Requester Email:"));
        grid.setWidget(1, 1, requesterEmail);
        grid.setWidget(2, 0, new Label("Requester Phone:"));
        grid.setWidget(2, 1, requesterPhone);
        grid.setWidget(3, 0, new Label("Dept. to be Billed:"));
        grid.setWidget(3, 1, departmentBilled);
        grid.setWidget(4, 0, new Label("Account Number:"));
        grid.setWidget(4, 1, accountNumber);

        panel.add(new HTML("<h1>Requester Information</h1>"));
        panel.add(grid);
        panel.add(errorHTML);

        return panel;
    }

    @Override
    public HasValue<String> getAccountNumberValue() {
        return accountNumber;
    }

    @Override
    public HasValue<String> getDepartmentBilledValue() {
        return departmentBilled;
    }

    @Override
    public HasHTML getErrorHTML() {
        return errorHTML;
    }

    @Override
    public HasValue<String> getRequesterEmailValue() {
        return requesterEmail;
    }

    @Override
    public HasValue<String> getRequesterNameValue() {
        return requesterName;
    }

    @Override
    public HasValue<String> getRequesterPhoneValue() {
        return requesterPhone;
    }

    @Override
    public void focusFirstBlankField() {
        if(accountNumber.getValue().isEmpty())
            accountNumber.setFocus(true);
        if(departmentBilled.getValue().isEmpty())
            departmentBilled.setFocus(true);
        if(requesterPhone.getValue().isEmpty())
            requesterPhone.setFocus(true);
        if(requesterEmail.getValue().isEmpty())
            requesterEmail.setFocus(true);
        if(requesterName.getValue().isEmpty())
            requesterName.setFocus(true);
    }

    @Override
    public void showErrors(List<String> errors) {
        if(errors == null || errors.size() == 0) {
            errorHTML.setHTML("");
            return;
        }

        Iterator<String> iter = errors.iterator();
        StringBuilder sb = new StringBuilder(iter.next());
        while(iter.hasNext()) {
            sb.append("<br />").append(iter.next());
        }

        errorHTML.setHTML(sb.toString());
    }

    @Override
    public void addKeyPressHandlers(KeyPressHandler handler) {
        requesterName.addKeyPressHandler(handler);
        requesterEmail.addKeyPressHandler(handler);
        requesterPhone.addKeyPressHandler(handler);
        departmentBilled.addKeyPressHandler(handler);
        accountNumber.addKeyPressHandler(handler);
    }

}