如何将键绑定附加到 JSplitPane 分隔符的向上和向下箭头

Question

我有JSplitPane，将oneTouchExpandable设置为true。

JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT);
        splitPane.setDividerSize(10);
        splitPane.setOneTouchExpandable(true);

问题是我不知道如何将键绑定附加到 JSplitPane 分隔符上的向上和向下箭头。对于向上箭头，我想要 Ctrl+U，对于向下 - Ctrl + D。

谢谢！

Answer 1

OneTouchExpandable显示的箭头按钮的实现是 UI 标签，并且会不必要地花费额外的工作来绑定它们。您可以轻松地在JSplitPane本身上使用键绑定，以使用 setDividerLocation(int) 控制JSplitPane分隔符位置。Ctrl + U增加，Ctrl + D减少。例如：

    Action incrDividerLoc = new AbstractAction() {
    public void actionPerformed(ActionEvent e) {
        JSplitPane srcSplitPan = (JSplitPane) e.getSource();
        (srcSplitPan).setDividerLocation(srcSplitPan.getDividerLocation()+10);
     }
   };
  Action decrDividerLoc = new AbstractAction() {
    public void actionPerformed(ActionEvent e) {
        JSplitPane srcSplitPan = (JSplitPane) e.getSource();
        (srcSplitPan).setDividerLocation(srcSplitPan.getDividerLocation()-10);
    }
   };
    jSplitPane1.getInputMap().put(KeyStroke.getKeyStroke(KeyEvent.VK_U, KeyEvent.CTRL_DOWN_MASK),
                                "increaseDivider");
    jSplitPane1.getInputMap().put(KeyStroke.getKeyStroke(KeyEvent.VK_D, KeyEvent.CTRL_DOWN_MASK),
                                "decreaseDivider");
    jSplitPane1.getActionMap().put("increaseDivider", incrDividerLoc);
    jSplitPane1.getActionMap().put("decreaseDivider", decrDividerLoc);

注意：方法 传递给setDividerLocation(int)小于 0 的值意味着应将除法器重置为尝试遵循左/上组件的首选大小的值。通知侦听器后，通过 setLastDividerLocation 更新最后一个分隔符位置。

Answer 2

问题是我不知道如何将键绑定附加到 JSplitPane 分隔符上的向上和向下箭头。

通常，您会尝试访问按钮的"操作"。在许多情况下，组件已经定义了您可以使用的操作。有关 JSplitPane 的默认绑定的列表，请参阅键绑定。不幸的是，没有支持一键式单击选项的操作。

因此，我们需要直接从UI访问按钮：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.plaf.basic.*;
public class SplitPaneDividerAction extends AbstractAction
{
    private boolean leading;
    public SplitPaneDividerAction(boolean leading)
    {
        this.leading = leading;
    }
    @Override
    public void actionPerformed(ActionEvent e)
    {
        JSplitPane splitPane = (JSplitPane)e.getSource();
        BasicSplitPaneUI ui = (BasicSplitPaneUI)splitPane.getUI();
        BasicSplitPaneDivider divider = ui.getDivider();
        if (leading)
            ((JButton)divider.getComponent(0)).doClick();
        else
            ((JButton)divider.getComponent(1)).doClick();
    }
    private static void createAndShowUI()
    {
        JPanel leading = new JPanel();
        leading.setPreferredSize( new Dimension(200, 100) );
        leading.setBackground( Color.BLUE );
        leading.setFocusable(true);
        JPanel trailing = new JPanel();
        trailing.setPreferredSize( new Dimension(200, 100) );
        trailing.setBackground( Color.RED );
        trailing.setFocusable(true);
        JSplitPane splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, leading, trailing);
        splitPane.setOneTouchExpandable(true);
        splitPane.setDividerLocation(100);
        InputMap im = splitPane.getInputMap(JSplitPane.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
        ActionMap am = splitPane.getActionMap();
        im.put(KeyStroke.getKeyStroke("control U"), "leading");
        im.put(KeyStroke.getKeyStroke("control D"), "trailing");
        am.put("leading", new SplitPaneDividerAction(true));
        am.put("trailing", new SplitPaneDividerAction(false));
        JFrame frame = new JFrame("SSCCE");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add( splitPane );
        frame.setSize(200, 200);
        frame.setLocationByPlatform( true );
        frame.setVisible( true );
    }
    public static void main(String[] args)
    {
        EventQueue.invokeLater(new Runnable()
        {
            public void run()
            {
                createAndShowUI();
            }
        });
    }
}

当然，这种方法只有在您的 LAF 从 BasicSplitPaneUI 扩展时才有效。