Question

我使用此方法更改表格单元格值，它改变了jtable但不改变文本文件！

public class user_AllBooks extends AbstractTableModel {

    BookInformation book_info = new BookInformation();
    String[] columns = new String[]{"Book Name", "Book Date", "Book ID", "Borrow Status"};
    ArrayList<BookInformation> bData = new ArrayList<BookInformation>();

    public user_AllBooks() {
        try {
            BufferedReader br = new BufferedReader(new FileReader("AllBookRecords.txt"));
            String line;
            while ((line = br.readLine()) != null) {
                bData.add(initializeBookData(line));
            }
            br.close();
        } catch (IOException ioe) {
        }
    }

    public BookInformation initializeBookData(String myline) {
        BookInformation book_infos = new BookInformation();
        String[] celledLine = myline.split("     ");
        book_infos.setBookName(celledLine[0]);
        book_infos.setBookDate(celledLine[1]);
        book_infos.setBookID(celledLine[2]);
        book_infos.setBorrowStatus(celledLine[3]);
        return book_infos;
    }

    @Override
    public String getColumnName(int col) {
        return columns[col];
    }

    @Override
    public int getRowCount() {
        if (bData != null) {
            return bData.size();
        } else {
            return 0;
        }
    }

    @Override
    public int getColumnCount() {
        return columns.length;
    }

    @Override
    public Object getValueAt(int rowIndex, int columnIndex) {
        BookInformation bookInf = bData.get(rowIndex);
        Object value;

        switch (columnIndex) {
            case 0:
                value = bookInf.getBookName();
                break;
            case 1:
                value = bookInf.getBookDate();
                break;
            case 2:
                value = bookInf.getBookID();
                break;
            case 3:
                value = bookInf.getBorrowStatus();
                break;
            default:
                value = "...";
        }
        return value;
    }


    @Override
  public void setValueAt(Object value, int row, int col)
    {
    BookInformation book_infos = bData.get(row);
    if (col==0)
    book_infos.setBookName((String)value);
    else if (col==1)
    book_infos.setBookDate((String)value);
    else if (col==2)
    book_infos.setBookID((String)value);
    else if (col==3)
    book_infos.setBorrowStatus((String)value);
    }
    }

第二课：

public class user_AllBooksM extends JFrame implements ActionListener {

    user_AllBooks uAllBooks = new user_AllBooks();
    final JTable bTable = new JTable(uAllBooks);
    JButton borrowButton;

    public user_AllBooksM() {
        setTitle("All Books");
        exitButton = new JButton("Exit");
        borrowButton = new JButton("Borrow");
        borrowButton.addActionListener(this);
        JPanel Bpanel = new JPanel();
        Bpanel.setLayout(new FlowLayout());
        JScrollPane sp = new JScrollPane(bTable);
        Bpanel.add(sp);
        Bpanel.add(borrowButton);
        this.add(Bpanel);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setBounds(300, 60, 550, 550);
        this.setResizable(false);
        this.setVisible(true);
    }

    @Override
    public void actionPerformed(ActionEvent event) {
        borrowInitialize(bTable.getSelectedRow());
    }

    public void borrowInitialize(int row) {
        if (uAllBooks.getValueAt(row, 3).equals("yes")) {
            JOptionPane.showMessageDialog(null, "This Book Was Borrowed");
        } else {
            uAllBooks.setValueAt("Yes", row, 3);
            uAllBooks.fireTableRowsUpdated(row, row);
        }
    }

    public static void main(String[] args) {
        new user_AllBooksM();
    }
}

我的文字档案：

sds wew     88     77     no
moon     889     988     yes
ccc     30     33     no
testing     76     77     no
yes     999     444     no
hoop     100     200     no
name     60     20     no
pp     14     15     no
vbnet     49     94     yes
sdsd     232     dsds     no
gh     12     21     no
khoyBook     322     233     no

Answer 1

将TableModelListener添加到TableModel。然后，无论何时首次更新事件，您都需要遍历TableModel的行/列并重新创建文本文件。

您的TableModel实现不正确。您尚未实现setValueAt（...）方法。

应该从TableModel的setValueAt（）方法调用“fireTableRowsUpdated（）”方法。不应该从ActionListener代码中调用它。

Answer 2

要在更改单元格值时更改文件内容，您应该将TableModelListener注册到关联的TableModel。并使用tableChanged方法实现文件编写逻辑。
以下是演示如何实现TableModelListener的示例代码。我希望这能为你提供一个很好的视角来实现你的任务：

import java.awt.BorderLayout;
import javax.swing.JFrame;
import javax.swing.JTable;
import javax.swing.JScrollPane;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;
import javax.swing.event.TableModelListener;
import javax.swing.event.TableModelEvent;
import javax.swing.table.TableModel;
import javax.swing.table.AbstractTableModel;
class TableDemo extends JFrame  implements TableModelListener
{
    private JTable table;
    private JScrollPane jsPane;
    private TableModel myModel;
    private JLabel label;
    public void prepareAndShowGUI()
    {
        myModel = new MyModel();
        table = new JTable(myModel);
        jsPane = new JScrollPane(table);
        label = new JLabel();
        myModel.addTableModelListener(this);
        getContentPane().add(jsPane);
        getContentPane().add(label,BorderLayout.SOUTH);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        pack();
        setVisible(true);
    }
    @Override
    public void tableChanged ( TableModelEvent evt)
    {
        int row = evt.getFirstRow();
        int col = evt.getColumn();
        label.setText("Value at ["+row+"]["+col+"] is changed to: "+myModel.getValueAt(row,col));
           //Write to your file here.
    }
    private class MyModel extends AbstractTableModel 
    {
        String[] columns = {
                            "Roll No.",
                            "Name"
                            };
        String[][] inData = {
                                {"1","Anthony Hopkins"},
                                {"2","James William"},
                                {"3","Mc. Donald"}
                            };
        @Override
        public void setValueAt(Object value, int row, int col)
        {
            inData[row][col] = (String)value;
            fireTableCellUpdated(row,col);
        }
        @Override
        public Object getValueAt(int row, int col)
        {
            return inData[row][col];
        }
        @Override
        public int getColumnCount()
        {
            return columns.length;
        }
        @Override 
        public int getRowCount()
        {
            return inData.length;
        }
        @Override
        public String getColumnName(int col)
        {
            return columns[col];
        }
        @Override 
        public boolean isCellEditable(int row, int col)
        {
            return true;
        }
    }
    public static void main(String st[])
    {
        SwingUtilities.invokeLater( new Runnable()
        {
            @Override
            public void run()
            {
                TableDemo td = new TableDemo();
                td.prepareAndShowGUI();
            }
        });
    }
}

效果JTable单元格值更改文本文件

2 个答案: