java - jTable 单元格背景颜色

Question

我正在尝试使用渲染器为 jTable 的单元格着色，但它们工作得不好，因为它们滞后于表格并使其无法看到。这是我的代码:

            TableCellRenderer Tcr = jTable1.getCellRenderer(x, y);
            Component c = Tcr.getTableCellRendererComponent(jTable1, jTable1.getValueAt(x, y), false, false, x, y);


            if(x > 0 && x < (jTable1.getRowCount()-1) && y > 1 && y < (jTable1.getColumnCount()-1)){
                if(!jTable1.getValueAt(x, y).equals(null) && !jTable1.getValueAt(x, y).equals("F") && !jTable1.getValueAt(x, y).equals(" ")){
                    if(!jTable1.getValueAt(x, y).toString().contains("/P") && !jTable1.getValueAt(x, y).toString().equals("P")){                            
                        if(Double.parseDouble(jTable1.getValueAt(x, y).toString()) > 24){
                            setBackground(java.awt.Color.red);

                        }
                    }
                }    
            }

我没有将它放入渲染器类中，因为它滞后，我将其放入 double for cicle 中，特别是放入第二个 cicle 中。我希望它为超过 24 的单元格着色，就像现在一样，如果我写

c.setBackground(Color.red);

它使表格完全着色

编辑

按照要求，我创建了一个小示例来描述我的问题，我不知道是否有特定的方法来发布可运行的示例，但以下代码(在netbeans中)代表了完整的程序:

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package fatturazione;

import ObjectModel.Timesheet;
import java.awt.Component;
import javax.swing.JLabel;
import javax.swing.table.TableCellRenderer;


/**
 *
 * @author xtphere
 */
public class Example extends javax.swing.JFrame {

    /**
     * Creates new form Main
     */
    public Example() {
        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() {

        jScrollPane1 = new javax.swing.JScrollPane();
        jTable1 = new javax.swing.JTable();
        CheckButton = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jTable1.setModel(new javax.swing.table.DefaultTableModel(
            new Object [][] {
                {null, null, null, null},
                {null, null, null, null},
                {null, null, null, null},
                {null, null, null, null}
            },
            new String [] {
                "Title 1", "Title 2", "Title 3", "Title 4"
            }
        ));
        jScrollPane1.setViewportView(jTable1);

        CheckButton.setText("Check the table");
        CheckButton.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                CheckButtonActionPerformed(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.PREFERRED_SIZE, 375, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(CheckButton))
                .addContainerGap(15, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 275, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(CheckButton)
                .addGap(0, 35, Short.MAX_VALUE))
        );

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

    private void CheckButtonActionPerformed(java.awt.event.ActionEvent evt) {                                            
        // TODO add your handling code here:
        int x, y, i = 1;


        for(x = 0; x < jTable1.getRowCount(); x++){

            for(y = 0;  y < jTable1.getColumnCount(); y++){

                TableCellRenderer Tcr = jTable1.getCellRenderer(x, y);
                Component c = Tcr.getTableCellRendererComponent(jTable1, jTable1.getValueAt(x, y), false, false, x, y);

                if(jTable1.getValueAt(x, y) == null)
                {
                    jTable1.setValueAt("P", x, y);
                }

                if(jTable1.getValueAt(x, y) != null && !jTable1.getValueAt(x, y).equals("F") && !jTable1.getValueAt(x, y).equals(" ")){
                        System.out.print(jTable1.getValueAt(x, y)+"\n");                          
                        if(!jTable1.getValueAt(x, y).toString().contains("/P") && !jTable1.getValueAt(x, y).toString().equals("P")){                            
                            System.out.print("prima del maggiore di 24");
                            if(Double.parseDouble(jTable1.getValueAt(x, y).toString()) > 24){
                                System.out.print("leggi il 25, almeno?");
                                c.setBackground(java.awt.Color.red);                                
                            }
                        }
                    }    


            }          
        } 


    }                                           

    /**
     * @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(Example.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(Example.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(Example.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(Example.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new Example().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JButton CheckButton;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTable jTable1;
    // End of variables declaration                   
}

Answer 1

首先，变量名称不应以大写字符开头。您的某些变量是正确的，其他变量则不正确。保持一致!!!

I've tried to color a cell of a jTable using the renderers, but they are useless they lag the table and make it impossible to see.

仅仅因为您不理解这个概念并不意味着它毫无用处。问题在于您的代码，而不是渲染器的概念。

您发布的代码毫无意义。您无法设置单个单元格的颜色。当单元格是渲染器时颜色就确定了，这就是为什么你需要使用渲染器。

it colors the table completely

是的，一旦设置了渲染器的背景，将来的所有单元格都将使用该颜色。在渲染每个单元格之前，您需要将颜色重置为默认值

the background must be red just in case it's a number AND it's higher than 24,

然后进行积极检查，忘记所有那些消极检查。

使用上述所有建议，您可能会拥有一个类似于以下内容的渲染器:

class ColorRenderer extends DefaultTableCellRenderer
{
    @Override
    public Component getTableCellRendererComponent(
        JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column)
    {
        super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);

        if (isSelected)
            setBackground( table.getSelectionBackground() );
        else
        {
            setBackground( table.getBackground() );

            try
            {
                int number = Integer.parseInt( value.toString() );

                if (number > 24)
                    setBackground( Color.RED );
            }
            catch(Exception e) {}
        }

        return this;
    }
}