comparison java/src/uk/ac/qmul/eecs/ccmi/gui/LoopComboBox.java @ 0:78b7fc5391a2

first import, outcome of NIME 2014 hackaton

+/*  
+ CCmI Editor - A Collaborative Cross-Modal Diagram Editing Tool
+  
+ Copyright (C) 2011  Queen Mary University of London (http://ccmi.eecs.qmul.ac.uk/)
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program 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 General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+package uk.ac.qmul.eecs.ccmi.gui;
+
+import java.awt.event.ItemEvent;
+import java.awt.event.KeyEvent;
+import java.util.Vector;
+
+import javax.swing.ComboBoxModel;
+import javax.swing.JComboBox;
+
+/**
+ * A ComboBox component which overrides the default behaviour when selecting items by the keyboard
+ * up and down arrow keys. When the top is reached, if the user presses the up arrow key  
+ * instead of blocking on the first item, the LoopComboBox loops forward to the last item. Likewise,
+ * when the bottom is reached and the user presses the down arrow key the LoopComboBox 
+ * loops back to the first item.  
+ *
+ */
+@SuppressWarnings("serial")
+public class LoopComboBox extends JComboBox {
+	public LoopComboBox(){
+		super();
+	}
+	
+	public LoopComboBox(Object[] items){
+		super(items);
+	}
+	
+	public LoopComboBox(ComboBoxModel aModel){
+		super(aModel);
+	}
+	
+	public LoopComboBox(Vector<?> items){
+		super(items);
+	}
+	
+	@Override
+	public void	processKeyEvent(KeyEvent e) {
+		if(dataModel.getSize() == 0){
+			super.processKeyEvent(e);
+		}else{
+			if(e.getKeyCode() == KeyEvent.VK_DOWN 
+					&& e.getID()==KeyEvent.KEY_PRESSED 
+					&& getSelectedIndex() == getItemCount()-1){
+				setSelectedIndex(0);
+				if(getItemCount() == 1)
+					fireOneItemStateChanged();
+			}else if(e.getKeyCode() == KeyEvent.VK_UP 
+					&& e.getID()==KeyEvent.KEY_PRESSED 
+					&& getSelectedIndex() == 0){
+				setSelectedIndex(getItemCount()-1);
+				if(getItemCount() == 1)
+					fireOneItemStateChanged();
+			}else
+				super.processKeyEvent(e);
+		}
+	}
+	
+	/*
+	 * when the comboBox has only one item the ItemStateChanged listeners ain't fired by default.
+	 * This behaviour has to be forced in order to have the item label to be spoken out by  
+	 * the narrator, in spite of the item number .  
+	 */
+	private void fireOneItemStateChanged(){
+		fireItemStateChanged(new ItemEvent(
+				this,
+				ItemEvent.ITEM_STATE_CHANGED,
+				getSelectedItem(),
+				ItemEvent.SELECTED
+		));
+	}
+}