Question

我正在尝试更改defaultTableModel中Object [] []数据中的值，但我在if (data[i][j] == userFolderName)获得了nullpointerexception我尝试将变量更改为“Kathy”，以防它不是正确读取userName但它仍然抛出异常。你能看看我的代码，看看我哪里出错了吗？

public class Statistics extends JPanel {
    public Object[][] data;
    public DefaultTableModel model;

public Statistics() {
    super(new GridLayout(1,0));
    String[] columnNames = {"Name", "Games Played", "Games Won"};
    Object[][] data = {
            {"Kathy", new Integer(5), new Integer(2)},
            {"Steve", new Integer(2), new Integer(0)},
    };
    model = new DefaultTableModel(data, columnNames);
    JTable table = new JTable(model);
    table.setFillsViewportHeight(true);
    table.setVisible(true);
    table.setEnabled(false);

    JScrollPane scrollPane = new JScrollPane(table);
    add(scrollPane);
}

public void addRow(Object[] objects) {
    model.addRow(objects);

}

public void updateGamesPlayed(String userFolderName, int gamesPlayed) {
    int rowCount = model.getRowCount();
    int columnCount = model.getColumnCount();
    for (int i = 0; i < rowCount; i++){
        for(int j = 0; j < columnCount; j++){
            if (data[i][j] == userFolderName){
                model.setValueAt(gamesPlayed, i, j+1);
            }
        }
    }

}


}

Answer 1

您有两个不同的data个对象 - 构造函数中的全局对象和本地对象。如果您在构造函数中将Object[][] data = {...};更改为data = new Object[][]{...};，那么它应该可以正常运行，因为您只设置本地值，而不是全局值。

Answer 2

顺便说一句

model.setValueAt(gamesPlayed, i, j+1);

这个j + 1会导致OutOfBoundsException

setValueAt（Object aValue，int row，int col）

2 个答案: