如何在左侧扩展jframe？

Question

我有三个JPanel 。 左右面板被隐藏。 默认情况下，只有中间面板可见。

当我按下一个按钮时，边框宽度将增加右侧面板的宽度，并且右侧面板变为可见。

我的问题是左侧面板，因为无法向左增加框架。

我的解决方案是：

public void mousePressed(MouseEvent e) {
    int frameWidth = frame.getBounds().width;
    int frameHeight = frame.getBounds().height;
    int panelWidth = leftPanel.getPreferredSize().width;
    Point currCoords = frame.getLocationOnScreen();

    if(!_leftPanelOpened) {
        frame.setSize(new Dimension(frameWidth + panelWidth, frameHeight));
        leftPanel.setVisible(true);
        frame.setLocation(currCoords.x - panelWidth, currCoords.y);
        _leftPanelOpened = true;
    }
    else {
        leftPanel.setVisible(false);
        frame.setSize(new Dimension(frameWidth - panelWidth, frameHeight));
        frame.setLocation(currCoords.x + panelWidth, currCoords.y);
        _leftPanelOpened = false;
    }
}

它可以工作，但是画面不久会闪烁。 我可以避免这种短暂的眨眼吗？

编辑：

public class Main {

    private static JPanel leftoption = new JPanel();
    private static JPanel rightoption = new JPanel();
    private static JFrame frame = new JFrame();
    private static JPanel leftPanel =  new JPanel();
    private static JPanel rightPanel =  new JPanel();
    private static JPanel _centerPanel =  new JPanel();
    private static boolean _leftPanelOpened = false;
    private static boolean _rightPanelOpened = false;

    public static void main(String[] args) {
        leftoption.setPreferredSize(new Dimension(50, 40));
        leftoption.setBackground(Color.CYAN);
        leftoption.addMouseListener(new MouseAdapter() {
            @Override
            public void mousePressed(MouseEvent e) {
                int frameWidth = frame.getBounds().width;
                int frameHeight = frame.getBounds().height;
                int panelWidth = leftPanel.getPreferredSize().width;
                Point currCoords = frame.getLocationOnScreen();

                if(!_leftPanelOpened) {
                    frame.setBounds(currCoords.x - panelWidth, currCoords.y, frameWidth + panelWidth, frameHeight);
                    leftPanel.setVisible(true);
                    _leftPanelOpened = true;
                }
                else {
                    leftPanel.setVisible(false);
                    frame.setBounds(currCoords.x + panelWidth, currCoords.y, frameWidth - panelWidth, frameHeight);
                    _leftPanelOpened = false;
                }
            }
            @Override
            public void mouseReleased(MouseEvent e) {

            }
        });

        rightoption.setPreferredSize(new Dimension(50, 40));
        rightoption.setBackground(Color.ORANGE);
        rightoption.addMouseListener(new MouseAdapter() {
            @Override
            public void mousePressed(MouseEvent e) {
                int frameWidth = frame.getBounds().width;
                int frameHeight = frame.getBounds().height;
                int panelWidth = rightPanel.getPreferredSize().width;
                if(!_rightPanelOpened) {
                    frame.setSize(new Dimension(frameWidth+panelWidth, frameHeight));
                    rightPanel.setVisible(true);
                    _rightPanelOpened = true;
                }
                else {
                    rightPanel.setVisible(false);
                    frame.setSize(new Dimension(frameWidth-panelWidth, frameHeight));
                    _rightPanelOpened = false;
                }
            }
            @Override
            public void mouseReleased(MouseEvent e) {

            }
        });


        _centerPanel.setPreferredSize(new Dimension(300, 600));
        _centerPanel.setBackground(Color.WHITE);
        _centerPanel.add(leftoption);
        _centerPanel.add(rightoption);

        leftPanel.setPreferredSize(new Dimension(300, 600));
        leftPanel.setBackground(Color.BLUE);
        leftPanel.setVisible(false);

        rightPanel.setPreferredSize(new Dimension(300, 600));
        rightPanel.setBackground(Color.RED);
        rightPanel.setVisible(false);

        frame.add(leftPanel, BorderLayout.LINE_START);
        frame.add(_centerPanel, BorderLayout.CENTER);
        frame.add(rightPanel, BorderLayout.LINE_END);

        frame.setSize(new Dimension(300, 600));
        frame.getContentPane().setBackground(Color.WHITE);

        frame.setVisible(true);
    }

}

Answer 1

您可以调用setBounds() ，它允许您同时设置位置和大小。 实际上，在后台， setSize()和setLocation()最终都会调用setBounds() 。

此外，您可以避免在面板安装到位之前调用setVisible(true) 。

因此，如何将您的方法更改为：

if(!_leftPanelOpened) {
    frame.setBounds(currCoords.x - panelWidth, currCoords.yframeWidth + panelWidth, frameHeight);
    leftPanel.setVisible(true);
    _leftPanelOpened = true;
}