001    /*
002     * Copyright 2006 Mat Gessel <mat.gessel@gmail.com>
003     * 
004     * Licensed under the Apache License, Version 2.0 (the "License"); you may not
005     * use this file except in compliance with the License. You may obtain a copy of
006     * the License at
007     * 
008     * http://www.apache.org/licenses/LICENSE-2.0
009     * 
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
012     * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
013     * License for the specific language governing permissions and limitations under
014     * the License.
015     */
016    package asquare.gwt.tk.client.ui;
017    
018    /**
019     * Implement if you wish to be notified of a DropDownPanel opening/closing.
020     * Useful if you need to modify your layout to accommodate changes in the DropDownPanel.
021     */
022    public interface DropDownListener
023    {
024            /**
025             * Called after a DropDownPanel's content element is made visible. 
026             * 
027             * @param sender the panel which was opened
028             */
029            void dropDownOpened(DropDownPanel sender);
030            
031            /**
032             * Called after a DropDownPanel's content element is hidden. 
033             * 
034             * @param sender the panel which was closed
035             */
036            void dropDownClosed(DropDownPanel sender);
037    }