com.google.appinventor.client.widgets.properties.AdditionalChoicePropertyEditor.java Source code

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Here is the source code for com.google.appinventor.client.widgets.properties.AdditionalChoicePropertyEditor.java

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// -*- 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.widgets.properties;

import static com.google.appinventor.client.Ode.MESSAGES;
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.Button;
import com.google.gwt.user.client.ui.HorizontalPanel;
import com.google.gwt.user.client.ui.Panel;
import com.google.gwt.user.client.ui.PopupPanel;
import com.google.gwt.user.client.ui.TextBox;
import com.google.gwt.user.client.ui.VerticalPanel;

/**
 * Property editor for situations where a property involves additional choices,
 * e.g. when choosing a layout, the choice of layout requires other dependent
 * properties to be set (e.g. table layout - number of rows and columns).
 *
 */
public abstract class AdditionalChoicePropertyEditor extends PropertyEditor {
    // a little padding to keep the panel from hitting the
    // edge of the screen
    private static final int ADDITIONAL_CHOICE_ONSCREEN_PADDING = 10;

    // UI elements
    private final TextBox summary;
    private PopupPanel popup;

    /**
     * Creates a new additional choice dialog.
     */
    protected AdditionalChoicePropertyEditor() {
        summary = new TextBox();
        summary.setReadOnly(true);
        summary.addClickHandler(new ClickHandler() {
            @Override
            public void onClick(ClickEvent event) {
                openAdditionalChoiceDialog();
            }
        });

        initWidget(summary);
    }

    /**
     * Initializes the additional choice panel.
     *
     * <p>This method must be called from any implementor's constructor.
     *
     * @param panel  panel containing additional choices
     */
    protected void initAdditionalChoicePanel(Panel panel) {
        Button cancelButton = new Button(MESSAGES.cancelButton());
        cancelButton.addClickHandler(new ClickHandler() {
            @Override
            public void onClick(ClickEvent event) {
                closeAdditionalChoiceDialog(false);
            }
        });
        Button okButton = new Button(MESSAGES.okButton());
        okButton.addClickHandler(new ClickHandler() {
            @Override
            public void onClick(ClickEvent event) {
                closeAdditionalChoiceDialog(true);
            }
        });

        HorizontalPanel buttonPanel = new HorizontalPanel();
        buttonPanel.add(cancelButton);
        buttonPanel.add(okButton);
        buttonPanel.setWidth("100%");
        buttonPanel.setHorizontalAlignment(HorizontalPanel.ALIGN_RIGHT);

        VerticalPanel contentPanel = new VerticalPanel();
        contentPanel.add(panel);
        contentPanel.add(buttonPanel);

        popup = new PopupPanel(false, true);
        popup.setAutoHideEnabled(true);
        popup.setWidget(contentPanel);
        popup.setStylePrimaryName("ode-MultipleChoicePropertyEditor");
    }

    @Override
    protected void updateValue() {
        summary.setText(getPropertyValueSummary() + "...");
    }

    /**
     * Returns a textual summary of the edited property's current value.
     *
     * <p>This is displayed to the user in the property editor pane before the
     * user decides to actually modify the property.
     */
    protected String getPropertyValueSummary() {
        return property.getValue();
    }

    /**
     * Sets the number of visible characters in the text box for the summary.
     *
     * @param length the number of visible characters
     */
    protected void setSummaryVisibleLength(int length) {
        summary.setVisibleLength(length);
    }

    /**
     * Opens the additional choice dialog.
     */
    protected void openAdditionalChoiceDialog() {
        popup.setPopupPositionAndShow(new PopupPanel.PositionCallback() {
            public void setPosition(int offsetWidth, int offsetHeight) {
                // adjust the x and y positions so that the entire panel
                // is on-screen
                int xPosition = getAbsoluteLeft();
                int yPosition = getAbsoluteTop();
                int xExtrude = xPosition + offsetWidth - Window.getClientWidth() - Window.getScrollLeft();
                int yExtrude = yPosition + offsetHeight - Window.getClientHeight() - Window.getScrollTop();
                if (xExtrude > 0) {
                    xPosition -= (xExtrude + ADDITIONAL_CHOICE_ONSCREEN_PADDING);
                }
                if (yExtrude > 0) {
                    yPosition -= (yExtrude + ADDITIONAL_CHOICE_ONSCREEN_PADDING);
                }
                popup.setPopupPosition(xPosition, yPosition);
            }
        });
    }

    protected final boolean isOpen() {
        return popup != null && popup.isShowing();
    }

    protected final void closeAdditionalChoiceDialog(boolean ok) {
        if (ok) {
            if (!okAction()) {
                // Dialog is not allowed to close.
                return;
            }
        } else {
            updateValue(); // Restore previous property value
        }
        popup.hide();
    }

    /**
     * Invoked when the additional choice dialog was exited by pressing the OK
     * button, or because closeAdditionalChoiceDialog was called with true.
     *
     * @return true if the dialog is allowed to close
     */
    protected abstract boolean okAction();
}