menuelementcomboshift.java

国外的j2me播放器软件

package no.auc.one.portableplayer.userinterface;

import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.Font;

/**
 * MenuElement which displays it's children at it's name tag, 
 * instead of normal browsing.
 */
public class MenuElementComboShift extends MenuElementContainer {
    private int currentChildIndex = 0;
    
    public MenuElementComboShift(String name) {
        super(name + ':');
    }
    
    public MenuElementComboShift(String name, MenuEventListener listener) {
        super(name + ':', listener);
    }

    public MenuElementComboShift(
        String name, 
        MenuEventListener listener,
        MenuElement[] children) 
    {
        super(name + ':', listener, children);
    }

    // XXX To be deprecated!
    public int getCurrentIndex() {
        return currentChildIndex;
    }
    
    // XXX To be deprecated!
    public MenuElement getCurrentChild() {
        return (MenuElement)children.elementAt(currentChildIndex);
    }

    public void paint(Graphics g) {
        // Draw "name:" at the left and "childname" at the right

        g.drawString(
            name,
            g.getClipX(),
            g.getClipY(),
            Graphics.TOP | Graphics.LEFT);

        if (children != null && children.size() > 0) {
            Font f = g.getFont();

            g.setClip(
                g.getClipX() + 
                ((100 > f.stringWidth(name)) ? 100 : f.stringWidth(name)), 
                g.getClipY(), 
                g.getClipWidth(), 
                g.getClipHeight());
                        
            String itemNameSuffix = "<->";
            int maxItemNameLength = g.getClipX() - f.stringWidth(itemNameSuffix); 
            
            String itemName = ((MenuElement)children.elementAt(
                    currentChildIndex)).toString();
            if (f.stringWidth(itemName) > maxItemNameLength) {                
                while(f.stringWidth(itemName) > maxItemNameLength + f.stringWidth("..")) {
                    itemName = itemName.substring(0, itemName.length() - 1);
                }
                
                itemName += "..";
            }
            
            itemName += itemNameSuffix;
            
            g.drawString(
                itemName,
                g.getClipWidth(),
                g.getClipY(),
                Graphics.TOP | Graphics.RIGHT);
        }
    }

    public void invokeAction() {
        if (children.size() > 0) {
            System.out.println("Invoke action of current child");
            ((MenuElement)children.elementAt(
                currentChildIndex)).invokeAction();
        }
    }

    public boolean prepareNavigateLeft() {
        if (currentChildIndex > 0) {
            currentChildIndex--;
        } else {
            currentChildIndex = (children.size() - 1);
        }

        return false;
    }

    public boolean prepareNavigateRight() {
        if (currentChildIndex < (children.size() - 1)) {
            currentChildIndex++;
        } else {
            currentChildIndex = 0;
        }

        return false;
    }
}