java - 一个 JPanel 中存在多个 JComboBox

Question

我有一个带有三个 JComboBox 的 JPanel。这是我写的代码:

public class Main {

private static String pat_order;
private static String PS_selection;
private static String ovlp_selection;


public static void main(String args[]) throws FileNotFoundException, IOException {
    Date start_time = new Date();
    try {
        GridBagConstraints gbc = new GridBagConstraints();
        final JComboBox jc = new JComboBox();
        jc.addItem("ARR");
        jc.addItem("SRR");

        final JComboBox jc1 = new JComboBox();
        jc1.addItem("RR");
        jc1.addItem("IQC");

        final JComboBox jc2 = new JComboBox();
        jc2.addItem("YES");
        jc2.addItem("NO");

        JPanel myPanel = new JPanel(new GridBagLayout());
        myPanel.add(jc, gbc); 
        myPanel.add(jc1, gbc); 
        myPanel.add(jc2, gbc);

        jc.addItemListener(new ItemListener() {
            public void itemStateChanged(ItemEvent ie) {
                String order = (String) jc.getSelectedItem();
                pat_order = order;
            }
        });


        jc1.addItemListener(new ItemListener() {
            public void itemStateChanged(ItemEvent ie) {

                String PS_method = (String) jc1.getSelectedItem();
                PS_selection = PS_method;
            }
        });


        jc2.addItemListener(new ItemListener() {
            public void itemStateChanged(ItemEvent ie) {

                String ovlp_user = (String) jc2.getSelectedItem();
                ovlp_selection = ovlp_user;
            }
        });


        if (pat_order == "ARR") {
            Arrays.sort(patterns_array, new ColumnComparator(0));
        } else if (pat_order == "SRR") {
            Arrays.sort(patterns_array, new ColumnComparator(1));
        }

       if (PS_selection == "RR") {
           System.out.println("RR");
                        } else if (PS_selection == "IQC") {
                              System.out.println("IQC");
                            }
       if (ovlp_selection == "YES") {
            Overlap a = new Overlap(Xdisc, final_patterns, k, Yresid, Xresid, projectname, pat_order, PS_selection);
        }

   } catch (Exception e) {
        System.err.println("Error: " + e.getMessage());
    } finally {
    }
    }
    }

问题是第一个 JComboBox 工作正常，但第二个和第三个 JComboBox 没有执行任何操作。如果您能帮助我解决这个问题，那就太好了。

Answer 1

您似乎正在运行您的 UI，就好像它是一个控制台程序一样。 UI 不是这样工作的，它们响应事件。这些事件可能以任何顺序、在任何时间发生...

对话框是控制执行流程的好方法。它们将阻止代码直到对话框关闭，以便您确定结果并采取适当的操作。

看看How to use dialogs了解更多详情...

当您在那里时，您可能还想查看Creating a UI with Swing这将解释更多您需要理解的概念。

就像 UI 需要某种窗 Eloquent 能显示在屏幕上的事实