java jtable custemrender rowcolor相对于2个值变化

Question

我是java初学者，在使用java表custemrenderer时遇到困难..我有名为“info”的数据库，其中包含3列调用“pvalue”，“pbankmoney”，“minvalue”..我制作java应用程序以在java表上查看它们..但我想让行背景颜色仅在“bankmoney”<“minvalue”(bankmoney低于minvalue)时不同..所以我使用java custemrenderer..但我有一些问题..firstone 正在使用表 CustomTableCellRenderer 我如何更改行颜色..我解释一下我的意思..当我说 jTable1.getColumnModel().getColumn(0).setCellRenderer(new CustomTableCellRenderer());
CustomTableCellRenderer 类仅在特定行收到第 0 列值，那么我可以比较那里 2 列之间的差异吗？但我认为有一种方法可以使用自定义渲染来更改前两列的颜色，而不是在单个单元格中。

然后我使用另一个 boolean 变量来实现我的目标..我在一开始就设置了一个名为“tabledif”的变量..并检查差异并将其更改为真或假，然后渲染类检查它并更改列颜色..是的，这不起作用..我发现该变量根据与minvalue和bankmoney值的差异正确更改..但是当我请求我的“rowidenty”类的 boolean 值时，每次它是我启动的值时它都会给出错误..为什么这个发生 boolean 问题？重要

1)我想使用 java custemrender 根据两个值之间的差异(从数据库获取)更改前 2 列颜色。

2)我想知道为什么 boolean 值总是给出 false，这是初始值，即使我已经更改为 true ??????

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package tablerowcustemrender;

import java.awt.Color;
import java.awt.Component;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.util.Vector;
import javax.swing.JTable;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableModel;

/**
 *
 * @author Madhawa
 */
public class rowidenty extends javax.swing.JFrame {

    public boolean tabledif=false;
    /**
     * Creates new form rowidenty
     */
    public rowidenty() {
        initComponents();
     jTable1.setShowGrid(true);
     jTable1.setShowVerticalLines(true);
     //jTable1.setGridColor(Color.gray);
    }

        public void search()
    {
       try{
           DefaultTableModel dm = (DefaultTableModel) jTable1.getModel();  
           Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
           Connection con = DriverManager.getConnection("jdbc:odbc:info");
           java.sql.Statement st=con.createStatement();
           ResultSet rs=st.executeQuery("select * from Table1");
           while(rs.next()){
               String tablename=rs.getString("pname");
               int tablemin= rs.getInt("minvalue");
               int tablemoney=rs.getInt("pbankmoney");
               if(tablemoney < tablemin)
               {
               tabledif=true;
               }
               else
               {
                   tabledif=false;
               }
               System.out.println(tablename+"  "+tablemoney+"  "+tablemin);
                       Vector<Object> data = new Vector<>(); 
                       data.add(tablename);  
                       data.add(tablemoney);  
                       data.add(tablemin);
                       dm.addRow(data); 

                       jTable1.getColumnModel().getColumn(0).setCellRenderer(new CustomTableCellRenderer());
                       jTable1.getColumnModel().getColumn(1).setCellRenderer(new CustomTableCellRenderer());
           }
        }
        catch(Exception e){
            System.out.println(e);
        }


    }
///////////////////////////////////////////////////////////////////





    /**
     * 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() {

        jButton1 = new javax.swing.JButton();
        jScrollPane1 = new javax.swing.JScrollPane();
        jTable1 = new javax.swing.JTable();
        jButton2 = new javax.swing.JButton();
        jButton3 = new javax.swing.JButton();
        jButton4 = new javax.swing.JButton();
        jButton5 = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jButton1.setText("action");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        jTable1.setBackground(new java.awt.Color(0, 204, 204));
        jTable1.setBorder(javax.swing.BorderFactory.createMatteBorder(5, 5, 5, 5, new java.awt.Color(255, 0, 102)));
        jTable1.setFont(new java.awt.Font("Tahoma", 0, 14)); // NOI18N
        jTable1.setModel(new javax.swing.table.DefaultTableModel(
            new Object [][] {

            },
            new String [] {
                "name", "money", "value"
            }
        ) {
            Class[] types = new Class [] {
                java.lang.String.class, java.lang.Integer.class, java.lang.Integer.class
            };

            public Class getColumnClass(int columnIndex) {
                return types [columnIndex];
            }
        });
        jTable1.setGridColor(new java.awt.Color(255, 204, 0));
        jTable1.setRowHeight(35);
        jTable1.setRowMargin(10);
        jTable1.setSelectionBackground(new java.awt.Color(255, 51, 153));
        jScrollPane1.setViewportView(jTable1);

        jButton2.setText("hide");
        jButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton2ActionPerformed(evt);
            }
        });

        jButton3.setText("show");
        jButton3.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton3ActionPerformed(evt);
            }
        });

        jButton4.setText("bool");
        jButton4.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton4ActionPerformed(evt);
            }
        });

        jButton5.setText("jButton5");
        jButton5.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton5ActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 504, Short.MAX_VALUE)
                    .addComponent(jButton1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                .addContainerGap())
            .addGroup(layout.createSequentialGroup()
                .addGap(45, 45, 45)
                .addComponent(jButton2)
                .addGap(27, 27, 27)
                .addComponent(jButton3)
                .addGap(116, 116, 116)
                .addComponent(jButton4)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(jButton5)
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 255, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(45, 45, 45)
                .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 35, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 39, Short.MAX_VALUE)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jButton2)
                    .addComponent(jButton3)
                    .addComponent(jButton4)
                    .addComponent(jButton5))
                .addGap(31, 31, 31))
        );

        pack();
    }// </editor-fold>                        

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // TODO add your handling code here:
        search();
    }                                        

    private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // TODO add your handling code here:
        jTable1.getColumnModel().getColumn(2).setMinWidth(0);
        jTable1.getColumnModel().getColumn(2).setMaxWidth(0);
    }                                        

    private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // TODO add your handling code here:
        jTable1.getColumnModel().getColumn(2).setMinWidth(150);
        jTable1.getColumnModel().getColumn(2).setMaxWidth(150);
         jTable1.getColumnModel().getColumn(2).setMaxWidth(150);
         jTable1.repaint();

    }                                        

    private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // TODO add your handling code here:
        tabledif=true;
    }                                        

    private void jButton5ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // TODO add your handling code here:
        System.out.println("hey  "+tabledif );
    }                                        

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(rowidenty.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(rowidenty.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(rowidenty.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(rowidenty.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new rowidenty().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify                     
    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
    private javax.swing.JButton jButton3;
    private javax.swing.JButton jButton4;
    private javax.swing.JButton jButton5;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTable jTable1;
    // End of variables declaration                   



      public class CustomTableCellRenderer extends DefaultTableCellRenderer{
  public Component getTableCellRendererComponent (JTable table, 
Object obj, boolean isSelected, boolean hasFocus, int row, int column) {
  Component cell = super.getTableCellRendererComponent(
   table, obj, isSelected, hasFocus, row, column);


rowidenty rowidenty1=new rowidenty();

if (rowidenty1.tabledif) {
    cell.setBackground(Color.cyan);
} else {
    cell.setBackground(Color.lightGray);
}


  System.out.println(obj+"  renderer   "+column+" bool "+rowidenty1.tabledif);
  return cell;
  }
      }
}

Answer 1

在单元格渲染中创建一个全新的 rowidenty 实例基本上会断开您与表中数据的连接...

public class CustomTableCellRenderer extends DefaultTableCellRenderer{
    public Component getTableCellRendererComponent (JTable table, Object obj, boolean isSelected, boolean hasFocus, int row, int column) {
        Component cell = super.getTableCellRendererComponent(table, obj, isSelected, hasFocus, row, column);

        // This is your problem....
        rowidenty rowidenty1=new rowidenty();

        if (rowidenty1.tabledif) {
            cell.setBackground(Color.cyan);
        } else {
            cell.setBackground(Color.lightGray);
        }


        System.out.println(obj+"  renderer   "+column+" bool "+rowidenty1.tabledif);
        return cell;
    }
}

相反，您需要使用 obj 值或向表询问有关该行的更多信息

已更新...

请记住，每一行都需要单独检查，因此尝试维护某种标志是没有意义的，除非每一行都有一个标志。

相反，您需要在每次调用 CustomTableCellRenderer 时提取该行所需的值，并根据您的需要更新背景...

public class CustomTableCellRenderer extends DefaultTableCellRenderer {

    @Override
    public Component getTableCellRendererComponent(JTable table,
                    Object obj, boolean isSelected, boolean hasFocus, int row, int column) {
        Component cell = super.getTableCellRendererComponent(
                        table, obj, isSelected, hasFocus, row, column);

        TableModel model = table.getModel();
        int money = (int) model.getValueAt(row, 1);
        int min = (int)model.getValueAt(row, 2);

        if (money < min) {
            cell.setBackground(Color.cyan);
        } else {
            cell.setBackground(Color.lightGray);
        }

        return cell;
    }
}