fr.putnami.pwt.core.widget.client.base.SimpleDropdown.java Source code

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Here is the source code for fr.putnami.pwt.core.widget.client.base.SimpleDropdown.java

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/**
 * This file is part of pwt.
 *
 * pwt is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser
 * General Public License as published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * pwt is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the
 * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
 * General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with pwt. If not,
 * see <http://www.gnu.org/licenses/>.
 */
package fr.putnami.pwt.core.widget.client.base;

import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.EventTarget;
import com.google.gwt.event.logical.shared.ValueChangeEvent;
import com.google.gwt.event.logical.shared.ValueChangeHandler;
import com.google.gwt.event.shared.HandlerRegistration;
import com.google.gwt.user.client.Event;
import com.google.gwt.user.client.Event.NativePreviewEvent;
import com.google.gwt.user.client.Event.NativePreviewHandler;
import com.google.gwt.user.client.History;
import com.google.gwt.user.client.Window;

import fr.putnami.pwt.core.theme.client.CssStyle;
import fr.putnami.pwt.core.widget.client.util.StyleUtils;

public class SimpleDropdown extends AbstractDropdown {

    private static final CssStyle STYLE_DROPDOWN = new SimpleStyle("dropdown");
    private static final CssStyle STYLE_MENU = new SimpleStyle("dropdown-menu");
    private static final CssStyle STYLE_TOGGLE = new SimpleStyle("dropdown-toggle");

    private static final CssStyle STYLE_OPEN = new SimpleStyle("open");
    private static final CssStyle STYLE_OPEN_UP = new SimpleStyle("open-up");
    private static final CssStyle STYLE_OPEN_LEFT = new SimpleStyle("open-left");

    private HandlerRegistration nativePreviewHandlerRegistration;
    private HandlerRegistration historyHandlerRegistration;

    private boolean open;

    public SimpleDropdown(String tagName) {
        super(tagName);

        StyleUtils.addStyle(this.anchor, SimpleDropdown.STYLE_TOGGLE);
        StyleUtils.addStyle(this.menuContainer, SimpleDropdown.STYLE_MENU);

        StyleUtils.addStyle(this, SimpleDropdown.STYLE_DROPDOWN);
    }

    public SimpleDropdown(String tagName, String label) {
        this(tagName);
        this.setLabel(label);
    }

    @Override
    public void close() {
        StyleUtils.removeStyle(this, SimpleDropdown.STYLE_OPEN);
        StyleUtils.removeStyle(this, SimpleDropdown.STYLE_OPEN_UP);
        StyleUtils.removeStyle(this, SimpleDropdown.STYLE_OPEN_LEFT);
        this.open = false;
        this.updateHandlers();
    }

    @Override
    public void open() {
        StyleUtils.addStyle(this, SimpleDropdown.STYLE_OPEN);
        Element menuElt = this.menuContainer.getElement();
        int topMenu = menuElt.getAbsoluteTop() - Window.getScrollTop();
        int menuHeight = menuElt.getOffsetHeight();
        int anchorHeight = this.anchor.getOffsetHeight();
        int clientHeight = Window.getClientHeight();
        if (topMenu + menuHeight > clientHeight && topMenu >= anchorHeight + menuHeight) {
            StyleUtils.addStyle(this, SimpleDropdown.STYLE_OPEN_UP);
        }
        int leftMenu = menuElt.getAbsoluteLeft() - Window.getScrollLeft();
        int menuWidth = menuElt.getOffsetWidth();
        int anchorWidth = this.anchor.getOffsetWidth();
        int clientWidth = Window.getClientWidth();
        if (leftMenu + menuWidth > clientWidth && leftMenu >= anchorWidth + menuWidth) {
            StyleUtils.addStyle(this, SimpleDropdown.STYLE_OPEN_LEFT);
        }
        this.open = true;
        this.updateHandlers();
    }

    @Override
    public void toggleOpen() {
        if (this.open) {
            this.close();
        } else {
            this.open();
        }
        this.anchor.setFocus(true);
    }

    public boolean isOpen() {
        return this.open;
    }

    private boolean eventTargetsDropDown(NativePreviewEvent event) {
        Event nativeEvent = Event.as(event.getNativeEvent());
        EventTarget target = nativeEvent.getEventTarget();
        if (Element.is(target)) {
            return this.getElement().isOrHasChild(Element.as(target));
        }
        return false;
    }

    private void updateHandlers() {
        if (this.nativePreviewHandlerRegistration != null) {
            this.nativePreviewHandlerRegistration.removeHandler();
            this.nativePreviewHandlerRegistration = null;
        }
        if (this.historyHandlerRegistration != null) {
            this.historyHandlerRegistration.removeHandler();
            this.historyHandlerRegistration = null;
        }

        if (this.open) {
            this.nativePreviewHandlerRegistration = Event.addNativePreviewHandler(new NativePreviewHandler() {
                @Override
                public void onPreviewNativeEvent(NativePreviewEvent event) {
                    if (!SimpleDropdown.this.eventTargetsDropDown(event)) {
                        int type = event.getTypeInt();
                        switch (type) {
                        case Event.ONMOUSEDOWN:
                        case Event.ONTOUCHSTART:
                            SimpleDropdown.this.close();
                            break;
                        default:
                            break;
                        }
                    }
                }
            });
            this.historyHandlerRegistration = History.addValueChangeHandler(new ValueChangeHandler<String>() {
                @Override
                public void onValueChange(ValueChangeEvent<String> event) {
                    SimpleDropdown.this.close();
                }
            });
        }
    }
}