Question

在我的项目中，我有一个滚动窗格，可以包含各种面板，具体取决于用户操作。顺便说一下，我想让每个面板都有一个固定的高度，然后再添加它们，它们应该显示在前面的下面。相反，他们根据现有面板的数量改变高度。我写了一个主要课程，目的是重现当前的行为，以及一个应该解释我的目标的图像。

图像：

代码：

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.ScrollPaneConstants;
import javax.swing.SwingUtilities;


public class MyClass {

    static JScrollPane myScrollPaneContent;
    static Box panelContainer;
    static int i=0;

    public static void main(String[] args)  {       
        SwingUtilities.invokeLater(new Runnable() {
            public void run(){   
                int i=0;
                //mainWindow
                    JFrame mainWindow = new JFrame("MyFrame");
                    mainWindow.setLayout(new BorderLayout());
                    mainWindow.setMinimumSize(new Dimension(1050,300));

                //panel to be placed in mainwindow (borderlayout.Center)
                //contains a menu + scrollpane
                    JPanel centerPanel = new JPanel();

                //Box for myScrollPaneContent
                panelContainer = Box.createVerticalBox(); 

                    //button for centerPanel
                    JButton button = new JButton("addPanel");
                    button.setBackground(Color.green);
                    button.addMouseListener(new MouseListener() {
                        @Override
                        public void mouseReleased(MouseEvent e) {
                            //nothing
                        }
                        @Override
                        public void mousePressed(MouseEvent e) {
                            //nothing
                        }

                        @Override
                        public void mouseExited(MouseEvent e) {
                            //nothing
                        }

                        @Override
                        public void mouseEntered(MouseEvent e) {
                            //nothing
                        }

                        @Override
                        public void mouseClicked(MouseEvent e) {
                            addPanel();
                        }

                    });
                    centerPanel.add(button);


                    myScrollPaneContent = new JScrollPane(panelContainer);
                    myScrollPaneContent.setPreferredSize(new Dimension(600,250));
                    myScrollPaneContent.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);

                    //all panels are added to the Box


                    //the box do not need to be added to scroll pane since it has been given into it s constructor

                    //the scrollpane is added to the centralpanel
                    centerPanel.add(myScrollPaneContent);

                    mainWindow.add(centerPanel,BorderLayout.CENTER);
                    mainWindow.add(Box.createVerticalGlue(),BorderLayout.SOUTH);


                    mainWindow.setVisible(true);
            }
        });
    }




    public static void addPanel(){
        switch(i++){
        case 0:
            //panel 1 for Box
            JPanel one = new JPanel();
            JLabel labOne = new JLabel("hello");
            one.add(labOne);
            one.setPreferredSize(new Dimension(1000,25));
            one.setBackground(Color.white);
            panelContainer.add(one);

            break;
        case 1:
            //panel 2 for Box
            JPanel two = new JPanel();
            JLabel labTwo = new JLabel("i am a label");
            two.add(labTwo);
            two.setPreferredSize(new Dimension(1000,30));
            two.setBackground(Color.yellow);
            panelContainer.add(two);
            break;
        case 2:
            //panel 3 for Box
            JPanel three = new JPanel();
            JLabel labThree = new JLabel("Bye bye");
            three.add(labThree);
            three.setPreferredSize(new Dimension(1000,30));
            three.setBackground(Color.gray);
            panelContainer.add(three);
            break;
        case 3:
            //panel 4 for Box
            JPanel four = new JPanel();
            JLabel labFour = new JLabel("boyz");
            four.add(labFour);
            four.setPreferredSize(new Dimension(1000,30));
            four.setBackground(Color.blue);
            panelContainer.add(four);
            break;
        default: 
            i=0;
            break;
        }
        myScrollPaneContent.revalidate();
        myScrollPaneContent.repaint();
    }
}

Answer 1

你想要这样的东西：

JPanel scrollPaneContainer = new JPanel( new BorderLayout() );
Box panelContainer = Box.createVerticalBox(); 
scrollPaneContainer.add(panelContainer, BorderLayout.PAGE_START);
JScrollPane myScrollPaneContent = new JScrollPane(scrollPaneContainer);

现在将尊重panelContainer的首选高度。如果有任何额外的空间，它将进入中心。如果空间不足，则会出现滚动条。

此外，您不应该使用静态变量。这是设计不佳的GUI的标志。您不应该在main（）方法中创建GUI组件。看看Swing tutorial的演示。它们向您展示了如何创建一个面板来保持Swing组件，然后将面板添加到框架中。

将固定大小的JPanel添加到jScrollPane

1 个答案: