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java - 选择列表中的项目后在面板上设置标签

转载 作者：行者123 更新时间：2023-11-30 07:25:41 26 4
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为什么标签不显示？

package javaapplication4;


import java.awt.Color;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.GridBagLayout;
import javax.swing.GroupLayout;
import javax.swing.GroupLayout.Alignment;
import javax.swing.JButton;
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class settingPanel extends javax.swing.JPanel {
    static JPanel con = new JPanel();
    static JFrame frame = new JFrame();
    JLabel jLabel1 = new JLabel();
    public JEditorPane htmlvi = new JEditorPane();

    /** Creates new form settingPanel */
    public settingPanel() {
        initComponents();
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {

        jTabbedPane1 = new javax.swing.JTabbedPane();
        jPanel1 = new javax.swing.JPanel();
        jScrollPane1 = new javax.swing.JScrollPane();
        jList1 = new javax.swing.JList();

        jList1.setModel(new javax.swing.AbstractListModel() {
            String[] strings = { "Item 1", "Item 2", "Item 3", "Item 4",
                    "Item 5" };

            public int getSize() {
                return strings.length;
            }

            public Object getElementAt(int i) {
                return strings[i];
            }
        });
        jList1.addListSelectionListener(new javax.swing.event.ListSelectionListener() {
            public void valueChanged(javax.swing.event.ListSelectionEvent evt) {
                jList1ValueChanged(evt);
            }
        });
        jScrollPane1.setViewportView(jList1);

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(
                jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(jPanel1Layout.createParallelGroup(
                javax.swing.GroupLayout.Alignment.LEADING).addGroup(
                jPanel1Layout
                        .createSequentialGroup()
                        .addComponent(jScrollPane1,
                                javax.swing.GroupLayout.PREFERRED_SIZE, 70,
                                javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addContainerGap(325, Short.MAX_VALUE)));
        jPanel1Layout.setVerticalGroup(jPanel1Layout.createParallelGroup(
                javax.swing.GroupLayout.Alignment.LEADING).addComponent(
                jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 272,
                Short.MAX_VALUE));

        jTabbedPane1.addTab("tab1", jPanel1);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
        this.setLayout(layout);
        layout.setHorizontalGroup(layout.createParallelGroup(
                javax.swing.GroupLayout.Alignment.LEADING).addComponent(
                jTabbedPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 400,
                Short.MAX_VALUE));
        layout.setVerticalGroup(layout.createParallelGroup(
                javax.swing.GroupLayout.Alignment.LEADING).addComponent(
                jTabbedPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 300,
                Short.MAX_VALUE));
    }// </editor-fold>

    private void addpanel() {
        JPanel pnl = new JPanel();
        pnl.setOpaque(false);
        pnl.setLayout(new GridBagLayout());
        pnl.add(new JButton());
        pnl.setVisible(true);
        jPanel1.setLocation(10, 30);
        jPanel1.add(pnl);
    }

    private void jList1ValueChanged(javax.swing.event.ListSelectionEvent evt) {

        JLabel write = new JLabel();

        // if(evt.getValueIsAdjusting()){
        String read = "<html><h2>" + jList1.getSelectedValue().toString()
                + "<UL>USB";
        addpanel();

        jPanel1.add(write);

    }

    // Variables declaration - do not modify
    private javax.swing.JList jList1;
    public static javax.swing.JPanel jPanel1;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTabbedPane jTabbedPane1;

    // End of variables declaration
    public static void main(String args[]) {

        frame.add(new settingPanel());
        // jPanel2.setLayout(new GridBagLayout());
        // jPanel2.add(new JButton());
        // jPanel2.setVisible(false);
        frame.pack();
        frame.setVisible(true);
        frame.setDefaultCloseOperation(3);
    }
}

最佳答案

您将 JLabel 添加到 jPanel1，它使用 GroupLayout 来显示其组件。 GroupLayout 需要知道每个组件必须放置在其垂直和水平组中的什么位置，并且它不知道将新标签放在哪里，因为您没有告诉。

我非常怀疑您的最终目标是在每次选择更改时向您的 GUI 添加一个新标签。您可能应该在 GUI 初始化时添加一个带有默认文本的唯一标签，并在选择更改时更改此标签的文本。

关于java - 选择列表中的项目后在面板上设置标签，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/10780024/

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