Java tutorial
// -*- mode: java; c-basic-offset: 2; -*- // Copyright 2009-2011 Google, All Rights reserved // Copyright 2011-2012 MIT, All rights reserved // Released under the Apache License, Version 2.0 // http://www.apache.org/licenses/LICENSE-2.0 package com.google.appinventor.client.wizards; import static com.google.appinventor.client.Ode.MESSAGES; import com.google.gwt.user.client.Command; import com.google.gwt.user.client.DOM; import com.google.gwt.user.client.Element; import com.google.gwt.user.client.Event; import com.google.gwt.user.client.Window; import com.google.gwt.user.client.ui.AbsolutePanel; import com.google.gwt.user.client.ui.Button; import com.google.gwt.user.client.ui.ClickListener; import com.google.gwt.user.client.ui.DeckPanel; import com.google.gwt.user.client.ui.DialogBox; import com.google.gwt.user.client.ui.HorizontalPanel; import com.google.gwt.user.client.ui.Panel; import com.google.gwt.user.client.ui.ScrollPanel; import com.google.gwt.user.client.ui.VerticalPanel; import com.google.gwt.user.client.ui.Widget; /** * A wizard controls a dialog box that cycles through a series of pages. * <p> * The user may decide to cancel the wizard before viewing or completing * all of the pages. In that case, the wizard is closed and no further * action is taken. * <p> * After all pages have been cycled through, the user may invoke * a finish command. Immediately before the command is invoked, * the wizard dialog will be closed automatically. * */ public abstract class Wizard extends DialogBox { // UI for button panel to switch between wizard pages private final HorizontalPanel buttonPanel; private final Button backButton; private final Button cancelButton; private final Button nextButton; private final Button okButton; // Wizard pages private final AbsolutePanel pagePanel; private final DeckPanel pageDeck; private int currentPageIndex; // Command to execute upon finishing the wizard (not executed on cancel) private Command finishCommand; // Command to execute upon canceling the wizard (can be null) private Command cancelCommand; // Indicates whether the browser area size should be considered when calculating the wizard size private final boolean adaptiveSizing; // Indicates modality of the wizard private final boolean modal; /** * Creates a new wizard. * <p> * Implementations are expected to build the wizard dialog in their * constructor. In particular, it is expected that * {@link #addPage(Panel)} and {@link #initFinishCommand(Command)} * will be called before the constructor terminates. * * @param title title displayed in wizard dialog box * @param modal indicates modality of the wizard * @param adaptiveSizing instead of using the minimal size for the * wizard also considers the size of the browser area */ protected Wizard(String title, boolean modal, boolean adaptiveSizing) { // Initialize UI // TODO(lizlooney) - investigate using built-in modality support. The // reasons for not using it initially are no longer valid. super(false, false); this.modal = modal; this.adaptiveSizing = adaptiveSizing; setStylePrimaryName("ode-DialogBox"); setText(title); ClickListener buttonListener = new ClickListener() { @Override public void onClick(Widget sender) { if (sender == cancelButton) { handleCancelClick(); } else if (sender == nextButton) { showNextPage(); } else if (sender == backButton) { showPreviousPage(); } else if (sender == okButton) { handleOkClick(); } } }; cancelButton = new Button(MESSAGES.cancelButton()); cancelButton.addClickListener(buttonListener); backButton = new Button(MESSAGES.backButton()); backButton.addClickListener(buttonListener); nextButton = new Button(MESSAGES.nextButton()); nextButton.addClickListener(buttonListener); okButton = new Button(MESSAGES.okButton()); okButton.addClickListener(buttonListener); buttonPanel = new HorizontalPanel(); buttonPanel.add(cancelButton); buttonPanel.add(backButton); buttonPanel.add(nextButton); buttonPanel.add(okButton); buttonPanel.setSize("100%", "24px"); pageDeck = new DeckPanel(); pageDeck.setSize("100%", "100%"); pagePanel = new AbsolutePanel(); pagePanel.add(pageDeck); pagePanel.setWidth("100%"); VerticalPanel contentPanel = new VerticalPanel(); contentPanel.add(pagePanel); contentPanel.add(buttonPanel); contentPanel.setSize("100%", "100%"); add(contentPanel); } @Override public boolean onEventPreview(Event event) { // Always allow event if capturing is enabled if (DOM.getCaptureElement() != null) { return true; } // If this is a modal wizard then only allow it if the target element is a child of this wizard if (modal) { Element target = DOM.eventGetTarget(event); return (target != null && DOM.isOrHasChild(getElement(), target)); } else { return super.onEventPreview(event); } } /** * {@inheritDoc} * * Subclasses may override this to perform additional actions * after the wizard is shown, such as explicitly setting the * initially focused widget. Remember to call {@code super.show()} * as the first action in such overriding methods. */ @Override public void show() { ensureInited(); // Wizard size (having it resize between page changes is quite annoying) int width = 480; int height = 320; if (adaptiveSizing) { width = Math.max(width, Window.getClientWidth() / 3); height = Math.max(height, Window.getClientHeight() / 2); } setPixelSize(width, height); super.show(); if (pageDeck.getWidgetCount() == 1) { buttonPanel.remove(backButton); buttonPanel.remove(nextButton); } // Show first wizard page currentPageIndex = 0; showCurrentPage(); } /** * Adds a new page to the end of the wizard. */ protected void addPage(Panel page) { page = new ScrollPanel(page); pageDeck.add(page); } public void setPagePanelHeight(int height) { pagePanel.setHeight(height + "px"); } /** * Sets the command to be executed upon finish (not on cancel). * May only be invoked once. */ protected void initFinishCommand(Command finishCommand) { if (this.finishCommand != null) { throw new IllegalStateException(); } this.finishCommand = finishCommand; } /** * Sets the command to be executed upon cancel. * May be invoked no more than once. */ protected void initCancelCommand(Command cancelCommand) { this.cancelCommand = cancelCommand; } /** * Ensures that this class is fully initialized. */ private void ensureInited() { if (pageDeck.getWidgetCount() == 0 || finishCommand == null) { throw new IllegalStateException(); } } /** * Invoked immediately after showing a new page * * @param pageNumber number of page to be shown */ protected void onPageInit(int pageNumber) { } /** * Invoked immediately before moving away from the current page. * * @param pageNumber number of current page */ protected void onPageFinish(int pageNumber) { } /** * Invoked immediately before closing the wizard. */ protected void onHide() { } /** * Shows the previous page. */ protected void showPreviousPage() { onPageFinish(currentPageIndex); currentPageIndex--; showCurrentPage(); onPageInit(currentPageIndex); } /** * Shows the next page. */ protected void showNextPage() { onPageFinish(currentPageIndex); currentPageIndex++; showCurrentPage(); onPageInit(currentPageIndex); } protected final void handleCancelClick() { hideWizard(); if (cancelCommand != null) { cancelCommand.execute(); } } protected final void handleOkClick() { if (okButton.isEnabled()) { hideWizard(); finishCommand.execute(); } } protected final Button getConfirmButton() { return okButton; } protected void disableOkButton() { okButton.setEnabled(false); } protected void enableOkButton() { okButton.setEnabled(true); } /* * Hides the wizard. * Note that we are not overriding hide() because it is called by center() which can some * ugliness! */ private void hideWizard() { onPageFinish(currentPageIndex); onHide(); hide(); } /* * Shows the wizard page for the currentPageIndex in the dialog box. */ private void showCurrentPage() { // Enable back button if the current page is not the first page backButton.setEnabled(currentPageIndex > 0); // Enable next button if the current page is not the last page otherwise enable finish button boolean isLastPage = currentPageIndex == pageDeck.getWidgetCount() - 1; nextButton.setEnabled(!isLastPage); okButton.setEnabled(isLastPage); // Show page pageDeck.showWidget(currentPageIndex); // Because pages are embedded in scroll panels it is important to set the size of the page to // the current height of the content panel pageDeck.getWidget(currentPageIndex).setHeight(pagePanel.getOffsetHeight() + "px"); } }