Question

我有一个JPanel，它包含一个JPanel和一个JButtons。在内部JPanel中，我有一些最初选择的JCheckBox。我已经向我的JButtons添加了一个actionListener，用于检查每个JCheckBox是否更改为未选择的动作执行。但它不起作用。这是我的代码，问题出在哪里？

public LimitPanel(String[] dates, int column) {

    GridLayout layout = new GridLayout(1 + dates.length, 0);
    setLayout(layout);
    setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
    setVisible(true);

    this.dates = dates;

    checks = new JCheckBox[dates.length][column-1];

    for (int i = 0; i < dates.length; i++) {

        for (int j = 0; j < column - 1; j++) {
            checks[i][j] = new JCheckBox();
            checks[i][j].setSelected(true);
            checks[i][j]
                    .setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
            add(checks[i][j]);

        }
    }
}
public JCheckBox[][] getChecks() {
    return checks;
}

在我的主要Clas中，我有另一种方法，包含：

ResultSet e = connect.select("Invi", "*");
        try {
            while (e.next()) {
                final int inviID = e.getInt("inviID");
                    JPanel pn = new JPanel();
                pn.setSize(d.width, d.height);
            pn.setLocation(0, 0);
                    pn.setLayout(new BoxLayout(pn, BoxLayout.PAGE_AXIS));

                    lp = new LimitPanel(st, 6);
                    pn.add(lp);



                    JButton sabt = new JButton("  ثبت  ");
                    sabt.addActionListener(new ActionListener() {

                        @Override
                        public void actionPerformed(ActionEvent arg0) {
                            System.out.println("saaaaaaaaaaaaaaaabt");
                            JCheckBox[][] jcb = new JCheckBox[lp.getDates().length][5];
                            jcb = lp.getChecks();
                            for (int i = 0; i < lp.getDates().length; i++)
                                for (int j = 0; j < 5; j++) {
                                    if (!jcb[i][j].isSelected()) {
                                        System.out.println("naaaaaaaaa");
                                        connect.insertLimit(inviID, (lp
                                                .getDates())[i], j+"");
                                    }

                                }

                        }
                    });
                    pn.add(sabt);

                    panels.add(pn);

                }
            } catch (SQLException e1) {
                e1.printStackTrace();
            }
            setContentPane(panels.get(p));
            revalidate();

我编辑它以包含必要的内容，我的问题是当我按下按钮时System.out.println("saaaaaaaaaaaaaaaabt");始终有效但我对复选框System.out.println("naaaaaaaaa");的操作无效。

Answer 1

您使用while（while (e.next()) {）来构建部分程序。在其中，您可以在每次迭代时创建对lp和JButton，sabt的新引用。

您的ActionListener只能引用已创建的lp的最后一个实例。这很可能是因为actionPerformed正在做你认为应该做的事情......

想想这样......如果我这样做......

lp = new new LimitPanel(st, 6);
lp = new new LimitPanel(st, 6);
lp = new new LimitPanel(st, 6);
lp = new new LimitPanel(st, 6);

JCheckBox[] = lp.getChecks();

lp的哪个实例我从

获取了复选框

更新了更多详情

// Create a new instance of "LimitPanel"
lp = new LimitPanel(st, 6);
// You can check this by using the hashCode of the object...
System.out.println(lp.hashCode());
pn.add(lp);

JButton sabt = new JButton("  ثبت  ");
sabt.addActionListener(new ActionListener() {

    @Override
    public void actionPerformed(ActionEvent arg0) {
        /*...*/
        // Use what ever was last assigned to "lp"
        jcb = lp.getChecks();
        // You can check this by using the hashCode of the object...
        System.out.println(lp.hashCode());
        /*...*/
    }
});

如果您确实希望ActionListener使用LimitPanel的特定实例，则应将该引用传递给ActionListener的特殊实例...

例如......

lp = new LimitPanel(st, 6);
// You can check this by using the hashCode of the object...
System.out.println(lp.hashCode());
pn.add(lp);

JButton sabt = new JButton("  ثبت  ");
sabt.addActionListener(new LimitActionHandler(lp));

LimitActionHandler ...

public class LimitActionHandler implements ActionListener {

    private LimitPanel limitPane;

    public LimitActionHandler(LimitPanel limitPane) {
        this.limitPane = limitPane;
    }

    @Override
    public void actionPerformed(ActionEvent arg0) {
        /*...*/
        // Use what ever was last assigned to "lp"
        jcb = limitPane.getChecks();
        // You can check this by using the hashCode of the object...
        System.out.println(limitPane.hashCode());
        /*...*/
    }
}

正如我在评论中所述，我认为从JCheckBox公开LimitPanel es是一个坏主意，因为它允许您的应用程序的其他部分不受限制地访问这些对象，不需要工作......

JCheckBox[] jcb = limitPane.getChecks();
for (JCheckBox cb : jcb) {
    cb.setSelected(false); //...
}
for (JCheckBox cb : jcb) {
    cb.getParent().remove(cb); //...
}

这非常危险。您可以争辩说您的应用程序不会执行这些操作，但您无法阻止它发生...

JCheckBox不会触发isselected

1 个答案: