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如何更新来自不同阶级的信息?
原标题:How do I update a JPanel with information from a different class?
  • 时间:2012-05-21 17:02:09
  •  标签:
  • java
  • jpanel

我创建了以下示例源,并想知道我需要做些什么才能用JTable中点击该行的JLabel来更新我的JPanel,该JLabel的信息来自该行。

我还想指出,这仅仅是一个简单的例子,因为由于这里有几个民间社会组织的成员,我对样本代码做了相当小的改进。

滚动测试(主机)

public class SwingTesting {

    private final JFrame frame;
    private final 表格tablePane;
    private final JSplitPane splitPane;
    private final JPanel infoPanel;
    private final JLabel infoLabel;

    public SwingTesting() {
        tablePane = new TablePane();
        infoPanel = new JPanel();
        frame = new JFrame();

        infoLabel = new JLabel();    //this is the panel i want to add the label to
        infoPanel.add(infoLabel);

        splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, tablePane, infoPanel);

        frame.add(splitPane);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new SwingTesting();
            }
        });
    }
} 

表格

public class 表格extends JPanel {

    private final JTable table;
    private final TableModel tableModel;
    private final ListSelectionModel listSelectionModel;

    public TablePane() {
        table = new JTable();
        tableModel = createTableModel();
        table.setModel(tableModel);
        table.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
        table.add(table.getTableHeader(), BorderLayout.PAGE_START);
        table.setFillsViewportHeight(true); 

        listSelectionModel = table.getSelectionModel();
        table.setSelectionModel(listSelectionModel);
        listSelectionModel.addListSelectionListener(new SharedListSelectionHandler());
        table.setSelectionModel(listSelectionModel);

        this.setLayout(new GridBagLayout());

        GridBagConstraints gbc = new GridBagConstraints();
        gbc.anchor = GridBagConstraints.NORTHWEST;
        gbc.fill = GridBagConstraints.BOTH;
        gbc.gridx = 0;
        gbc.gridy = 0;
        gbc.gridheight = 1;
        gbc.gridwidth = 3;
        gbc.insets = new Insets(5, 5, 5, 5);
        gbc.ipadx = 2;
        gbc.ipady = 2;
        gbc.weightx = 1;
        gbc.weighty = 1;

        this.add(new JScrollPane(table), gbc);
    }

    private TableModel createTableModel() {
        DefaultTableModel model = new DefaultTableModel(
            new Object[] {"Car", "Color", "Year"}, 0 
        ){
            @Override public boolean isCellEditable(int row, int column) {
                return false;
            }
        };

        addTableData(model);
        return model;
    }

    private void addTableData(DefaultTableModel model) {
        model.addRow(new Object[] {"Nissan", "Black", "2007"});
        model.addRow(new Object[] {"Toyota", "Blue", "2012"});
        model.addRow(new Object[] {"Chevrolet", "Red", "2009"});
        model.addRow(new Object[] {"Scion", "Silver", "2005"});
        model.addRow(new Object[] {"Cadilac", "Grey", "2001"});
    }


    class SharedListSelectionHandler implements ListSelectionListener {

        //When selection changes i want to add a label to the panel
        //currently it just prints out the info from the selected row    
        @Override
        public void valueChanged(ListSelectionEvent e) {
            ListSelectionModel lsm = (ListSelectionModel) e.getSource();
            String contents = "";

            if(lsm.isSelectionEmpty()) {
                System.out.println("<none>");
            } else {
                int minIndex = lsm.getMinSelectionIndex();
                int maxIndex = lsm.getMaxSelectionIndex();
                for(int i = minIndex; i <= maxIndex; i++) {
                    if(lsm.isSelectedIndex(i)) {
                        for(int j = 0; j < table.getColumnCount(); j++) {
                            contents += table.getValueAt(i, j) + " ";
                        }
                    }
                }
                System.out.println(contents);
            }
        }        
    }
}

So I m wondering how to access that JPanel from the ListSelectionListener. Should I just pass the panel to the 表格class? Or is there a more proper way to do this?

而且,我的ListSectionListSearingListList-List-List-List-List-List-Listener 打印了行信息两次 出于某种原因,我搞砸了循环吗?

<强 > EDIT

public class 表格extends JPanel {

    private final JTable table;
    private final TableModel tableModel;
    private final ListSelectionModel listSelectionModel;

    private final displayPanel;

    public TablePane() {
        //removed code for reading purposes
    }

    //IDE says issue with thinking displayPanel may have already been initialized
    public TablePane(JPanel panel) {
        //this();
        //displayPanel = panel;
    }


    //ListSelectionListener uses panel.add(jlabel)

}

是否简单到要关闭 final吗?

最佳回答

您可以将 JLabel 对象传递给 TablePane 对象( 在 TablePane s 构建器中, 或者提供自定义的 Label() 方法) 。 然后您可以使用 StringBuilder 来创建需要贴在标签上的文本, 并在标签上用 StringBuilder 对象( 通过其 < code>toString() 方法) 的共通词调 < code> 。

我认为您正在打印每平方厘米两次, 因为 valued changed 方法被调用两次: 一次在取消当前行选取的通知中, 一次在选择新行的通知中 。

问题回答

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