如何制作可编辑的 SWT 组合，允许用户仅键入组合中的项目

Question

我有一个 SWT，Combo其中我有一些字符串列表设置为Combo.

Combo 应该可以这样编辑：

1. 当用户输入一个不存在的项目时，不应允许输入和
2. 当用户输入现有项目时，应根据键入的每个键进行提示。

请让我知道您对如何实现这一目标的建议？

Answer 1

我在这里找到了一个例子：

http://my.oschina.net/uniquejava/blog/87573

我稍微修改了一下，所以Combo如果没有找到匹配，它会清除：

private static String[] items   = new String[] { "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday" };

public static void main(String[] args)
{
    Display display = new Display();
    Shell shell = new Shell(display);
    shell.setText("StackOverflow");
    shell.setLayout(new FillLayout());

    Combo combo = new Combo(shell, SWT.BORDER);
    for (int i = 0; i < items.length; i++)
    {
        combo.add(items[i]);
    }

    addAutoCompleteFeature(combo);

    shell.pack();
    shell.open();
    while (!shell.isDisposed())
    {
        if (!display.readAndDispatch())
        {
            display.sleep();
        }
    }
    display.dispose();
}

public static void addAutoCompleteFeature(Combo combo)
{
    // Add a key listener
    combo.addKeyListener(new KeyAdapter()
    {
        public void keyReleased(KeyEvent keyEvent)
        {
            Combo cmb = ((Combo) keyEvent.getSource());
            setClosestMatch(cmb);
        }

        // Move the highlight back by one character for backspace
        public void keyPressed(KeyEvent keyEvent)
        {
            if (keyEvent.keyCode == SWT.BS)
            {
                Combo cmb = ((Combo) keyEvent.getSource());
                Point pt = cmb.getSelection();
                cmb.setSelection(new Point(Math.max(0, pt.x - 1), pt.y));
            }
        }

        private void setClosestMatch(Combo combo)
        {
            String str = combo.getText();
            String[] cItems = combo.getItems();
            // Find Item in Combo Items. If full match returns index
            int index = -1;
            for (int i = 0; i < cItems.length; i++)
            {
                if (cItems[i].toLowerCase().startsWith(str.toLowerCase()))
                {
                    index = i;
                    break;
                }
            }

            if (index != -1)
            {
                Point pt = combo.getSelection();
                combo.select(index);
                combo.setText(cItems[index]);
                combo.setSelection(new Point(pt.x, cItems[index].length()));
            }
            else
            {
                combo.setText("");
            }
        }
    });
}