java - 如果在 JTable 中重复，则更新值

Question

我在检查 JTable 中的重复值时遇到问题。用户输入“产品代码”和“金额”，应用程序正在使用“产品代码”查找项目名称并将其添加到表值中。我想检查 JTable 中的重复项，但我不知道该怎么做。我希望用户选择例如代码:55 和数量 3，然后它被添加到 JTable 但是如果用户再次输入 55 和数量 5，它会添加另一行，我想要的是更新数量 3 + 5。

这就是我到目前为止所做的。

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Vector;

import javax.swing.JButton;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;

public class StockBasket extends JPanel implements ActionListener {
    private JTable table;
    private Vector rows, columns;
    private DefaultTableModel tabModel;
    private JScrollPane scrollPane;
    private JButton addBtn, deleteBtn;
    private JPanel mainPanel, buttonPanel;
    private String productName;
    private String spinnerAmount;
    private int quantityDbInt;
    private int amountInt;
public StockBasket() {
    rows = new Vector();
    columns = new Vector();
    String[] columnNames = { "Amount to update", "Product name",
            "Total in stock after update" };
    addColumns(columnNames);

    tabModel = new DefaultTableModel();
    tabModel.setDataVector(rows, columns);

    table = new JTable(tabModel);
    table.changeSelection(0, 0, false, false);
    scrollPane = new JScrollPane(table);// ScrollPane
    scrollPane.setPreferredSize(new java.awt.Dimension(500, 200));

    buttonPanel = new JPanel();
    addBtn = new JButton("ADD TO UPDATE");
    deleteBtn = new JButton("DELETE");
    deleteBtn.setEnabled(false);

    buttonPanel.add(addBtn);
    buttonPanel.add(deleteBtn);

    addBtn.addActionListener(this);
    deleteBtn.addActionListener(this);

    mainPanel = new JPanel();
    mainPanel.setSize(450, 300);
    mainPanel.setLayout(new BorderLayout());
    mainPanel.add("Center", scrollPane);
    mainPanel.add("North", buttonPanel);
    add(mainPanel);
    setVisible(true);
}

public void actionPerformed(ActionEvent source) {
    if (source.getSource() == (JButton) addBtn) {
        addBtnChecks();
    } else if (source.getSource() == (JButton) deleteBtn) {
        deleteRow(table.getSelectedRow());
    }
}

private void addBtnChecks() {
    productName = new MyDatabase(3).getName();
    amountInt = Integer.parseInt(UpdateStock.getAmount().getValue()
            .toString());
    if (new MyDatabase(3).getQuantity() == null) {
        // if the answer from db is null do not parseInt
    } else {
        quantityDbInt = Integer.parseInt(new MyDatabase(3).getQuantity());
    }
    if (productName == null) {
        UpdateStock.getErrorMsg().setText("Enter correct code");

    } else if (amountInt == 0) {
        UpdateStock.getErrorMsg().setText("Please enter correct amount");

    } else {
        addRow();
        UpdateStock.getAmount().setValue(0);
        UpdateStock.getStockNo().setText("");
        UpdateStock.getErrorMsg().setText("");
        deleteBtn.setEnabled(true);
    }
}

private void addColumns(String[] colName) {
    for (int i = 0; i < colName.length; i++)
        columns.addElement(colName[i]);
}

private void addRow() {
    Vector r = new Vector();
    r = createNewElement();
    rows.addElement(r);
    table.addNotify();
}

private Vector createNewElement() {
    Vector t = new Vector();
    spinnerAmount = UpdateStock.getAmount().getValue().toString();
    int spinnerAmountInt = Integer.parseInt(spinnerAmount);
    // read product name from database
    productName = new MyDatabase(3).getName();
    // itemsInStock - get value from db and add amount added by user
    int itemsInStock = quantityDbInt + spinnerAmountInt;
    t.addElement(spinnerAmount);
    t.addElement(productName);
    t.addElement(itemsInStock);
    return t;
}

private void deleteRow(int index) {
    // makes the first row always selected
    table.changeSelection(0, 0, false, false);
    int size = tabModel.getRowCount();
    if (size == 1) { // can't delete when no items
        deleteBtn.setEnabled(false);
    }
    if (index != -1) { // At least one Row in Table
        rows.removeElementAt(index);
        table.addNotify();
    }
}

}

Answer 1

有很多方法可以做到这一点。最好的方法涉及数据模型(带有数量的股票列表)和表模型(以 JTable 理解的方式表达它的适配器)之间的清晰分离。

以 List<StockHolding> 开头其中 StockHolding是一个 super 简单的类，用于保存一行数据。

public class StockHolding {
  private String product;
  private int quantity;
}

(在构造函数中添加和getProduct/getQuantity)

现在当您输入新产品+金额...

addRequest(String product, int amount) {
  StockHolding holding = findInList(product, myList);
  if (holding == null) {
    myList.add(new StockHolding(product, amount));
  } else {
    holding.setQuantity(amount+holding.getQuantity());
  }

完成这项工作的关键是根据此列表来表达您的表模型。 getRowCount()返回 myList.size()单元格值为 getValue(myList.get(rowNum), columnNum)其中 getValue()将列号分别映射到产品或金额。

这里的重要一课是，将表表达问题与存储数据问题分开可以使每个问题更容易解决。