GridLayout ButtonPanel 未显示指定的行/列

Question

所以这段代码明确表示JPanelselectPanel 应该有三行一列，但是，当我运行它时，我得到了这个结果，只是无法弄清楚我做错了什么。大部分代码与我认为的问题无关。开头是我制作给我带来问题的面板（selectPanel），结尾是将该面板添加到 JFrame 的地方（roiguide）。

代码结果：

    JPanel selectPanel = new JPanel();
    selectPanel.setLayout(new GridLayout(3,1,0,0));
    selectPanel.setBorder(BorderFactory.createEmptyBorder(10,10,10,10));

    imp.getWindow().toFront();
    IJ.setTool(Toolbar.RECTANGLE);

    referenceButton = new JButton("Add reference region");
    referenceButton.setEnabled(true);
    referenceButton.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            refDefine();
        }
    });
    refLabel = new JLabel(" ("+printformat.format(rno)+"/1)");
    selectPanel.add(referenceButton);
    selectPanel.add(refLabel);

    backgroundButton = new JButton("Add background region");
    backgroundButton.setEnabled(true);
    backgroundButton.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            brDefine();
        }
    });
    backgroundLabel = new JLabel(" ("+printformat.format(bno)+"/"+printformat.format(spotno)+")");
    selectPanel.add(backgroundButton);
    selectPanel.add(backgroundLabel);

    spotButton = new JButton("Add spot");
    spotButton.setEnabled(true);
    spotButton.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            spotDefine();
        }
    });
    spotLabel = new JLabel(" ("+printformat.format(sno)+"/"+printformat.format(spotno)+")");
    selectPanel.add(spotButton);
    selectPanel.add(spotLabel);

    JPanel editPanel = new JPanel();
    selectPanel.setLayout(new GridLayout(2,1,20,20));
    selectPanel.setBorder(BorderFactory.createEmptyBorder(10,10,10,10));

    jComboBox1 = new JComboBox();
    editPanel.add(jComboBox1);

    JButton editButton = new JButton("Edit ROIs");
    editButton.setEnabled(true);
    editButton.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            String item = (String) jComboBox1.getSelectedItem();
            Roi roi = overlay.get(overlay.getIndex(item));
        }
        });
    editPanel.add(editButton);

    // Create the buttonPanel, which has the "Cancel" and "OK" buttons
    JPanel buttonPanel = new JPanel();
    buttonPanel.setLayout(new GridLayout(1,2,20,20));
    buttonPanel.setBorder(BorderFactory.createEmptyBorder(10,10,10,10));
    JButton cancelButton = new JButton("Cancel");
    cancelButton.setEnabled(true);
    cancelButton.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            didCancel = true;
            roiguide.dispose();
            overlay.clear();
        }
    });
    buttonPanel.add(cancelButton);

    JButton okButton = new JButton("OK");
    okButton.setEnabled(true);
    okButton.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            if(current!=roino){
                IJ.error("ROI Manager","Please select " + roino + " regions of interest.");
            }else{
                canContinue=true;
                roiguide.dispose(); 
            }
        }
    });
    buttonPanel.add(okButton);

    // Create and populate the JFrame
    roiguide = new JFrame("Add regions of interest:");
    roiguide.getContentPane().add(selectPanel, BorderLayout.NORTH);
    roiguide.getContentPane().add(editPanel, BorderLayout.WEST);
    roiguide.getContentPane().add(buttonPanel, BorderLayout.EAST);
    roiguide.pack();
    roiguide.setLocation(400,400);
    roiguide.setVisible(true);
    roiguide.setResizable(false);

Answer 1

新功能的添加打破了显示

那么你知道你改变了什么，所以你应该知道从哪里开始寻找：

这看起来很可疑：

JPanel editPanel = new JPanel();
selectPanel.setLayout(new GridLayout(2,1,20,20));