com.retech.reader.web.client.ui.widget.DateButton.java Source code

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Here is the source code for com.retech.reader.web.client.ui.widget.DateButton.java

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/*
 * Copyright 2011 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */
package com.retech.reader.web.client.ui.widget;

import com.google.gwt.editor.client.IsEditor;
import com.google.gwt.editor.client.LeafValueEditor;
import com.google.gwt.editor.client.adapters.TakesValueEditor;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
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.i18n.client.DateTimeFormat;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.user.client.ui.HasValue;
import com.google.gwt.user.client.ui.PopupPanel;
import com.google.gwt.user.datepicker.client.DatePicker;

import java.util.Date;

/**
 * A button that shows a {@link DatePicker} when clicked.
 */
public class DateButton extends Composite implements HasValue<Date>, IsEditor<LeafValueEditor<Date>> {

    private final Button button;
    private Date date;
    private final DateTimeFormat dateFormat = DateTimeFormat.getFormat("EE, MMM d, yyyy");
    private final DatePicker datePicker;
    private final PopupPanel datePickerPopup;
    private LeafValueEditor<Date> editor;

    public DateButton() {
        button = new Button();
        initWidget(button);

        // Create the DatePicker popup.
        datePicker = new DatePicker();
        datePickerPopup = new PopupPanel(true, false);
        datePickerPopup.setWidget(datePicker);
        datePickerPopup.setGlassEnabled(true);

        // Show the DatePicker popup on click.
        button.addClickHandler(new ClickHandler() {
            @Override
            public void onClick(final ClickEvent event) {
                datePicker.setValue(date, false);
                datePickerPopup.center();
            }
        });

        // Push the new value into the button.
        datePicker.addValueChangeHandler(new ValueChangeHandler<Date>() {
            @Override
            public void onValueChange(final ValueChangeEvent<Date> event) {
                setValue(event.getValue(), true);
                datePickerPopup.hide();
            }
        });

        // Set the default date.
        setValue(null);
    }

    @Override
    public HandlerRegistration addValueChangeHandler(final ValueChangeHandler<Date> handler) {
        return addHandler(handler, ValueChangeEvent.getType());
    }

    @Override
    public LeafValueEditor<Date> asEditor() {
        if (editor == null) {
            editor = TakesValueEditor.of(this);
        }
        return editor;
    }

    @Override
    public Date getValue() {
        return date;
    }

    @Override
    public void setValue(final Date value) {
        setValue(value, false);
    }

    @Override
    public void setValue(final Date value, final boolean fireEvents) {
        Date oldValue = getValue();
        this.date = value;
        if (value == null) {
            button.setText("");
        } else {
            button.setText(dateFormat.format(date));
        }

        if (fireEvents) {
            ValueChangeEvent.fireIfNotEqual(this, oldValue, value);
        }
    }
}