我的程序中有多个复选框。我希望用户仅选择3个复选框,并且选中其中3个复选框时,应禁用其他复选框。此外,如果未选中任何一项,则应启用所有其他选项。

最佳答案

这是带有几乎完整源代码的解决方案:

public class TestProgram {

    public static JCheckBox[] checkList = new JCheckBox[10];

    public static void main(String[] args) {

        Listener listener = new Listener();

        for (int i = 0; i < 10; ++i) {
            checkList[i] = new JCheckBox("CheckBox-" + i);
            checkList[i].addItemListener(listener);
        }

        //
        // The rest of the GUI layout job ...
        //
    }

    static class Listener implements ItemListener {

        private final int MAX_SELECTIONS = 3;

        private int selectionCounter = 0;

        @Override
        public void itemStateChanged(ItemEvent e) {
            JCheckBox source = (JCheckBox) e.getSource();

            if (source.isSelected()) {
                selectionCounter++;
                // check for max selections:
                if (selectionCounter == MAX_SELECTIONS)
                    for (JCheckBox box: checkList)
                        if (!box.isSelected())
                            box.setEnabled(false);
            }
            else {
                selectionCounter--;
                // check for less than max selections:
                if (selectionCounter < MAX_SELECTIONS)
                    for (JCheckBox box: checkList)
                        box.setEnabled(true);
            }
        }
    }
}

09-10 10:01
查看更多