java - 从另一个类调用gui，但在代码终止后出现

Question

我有一个类，它使用 jcombobox 和 jtextfield init 创建一个框架，用户在其中插入一些数据。然后我有另一个类，其中用户通过 Swing 调用该类。尽管 swing 类工作正常，但当我从其他类调用它时，它只会在程序终止后才会出现。我需要将其打开，直到用户插入数据，然后单击“确定”，以便输入的数据可以在代码中进一步使用。

我用这个调用 swing 类 main:

new constraints();
        constraints.main(null);

Swing 类主要是:

    public static void main(String[] args)
            {
                Runnable runnable = new Runnable()
                {
                    @Override
                    public void run()
                    { 
                        new constraints().displayGUI();
                    }
                };
                EventQueue.invokeLater(runnable);
        }

完整代码:

    public class constraints {



        private static JTextField tField;
        private MyDocumentFilter documentFilter;
        private JLabel amountLabel;
        private static String amountString = "Select Quantity of Products (in ktones): ";
        public static String textstr = "" ;
        public static String sig="" ;
        public static String sigfinal="";

        private void displayGUI()
        {
          // final JFrame frame = new JFrame("Constraints");

            final JDialog dialog = new JDialog();
           // frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
            dialog.setDefaultCloseOperation(
                    JDialog.DISPOSE_ON_CLOSE);

            amountLabel = new JLabel(amountString);

            JPanel contentPane = new JPanel();
            contentPane.setBorder(
                BorderFactory.createEmptyBorder(5, 5, 5, 5));
            tField = new JTextField(10);

            amountLabel.setLabelFor(tField);

            String[] Strings = { "Less", "Equal", "More"};
            final JComboBox combo = new JComboBox(Strings) ;
            combo.setSelectedIndex(0);

            JButton button = new JButton("Ok");
            button.addActionListener(new ActionListener(){
                   public void actionPerformed(ActionEvent ae){

                            textstr = tField.getText();



                            sig = (String) combo.getSelectedItem();

                            if (sig=="Less") {
                                sigfinal="l";
                            }else if (sig=="Equal"){
                                sigfinal="e" ;
                            }else if (sig=="More"){
                                sigfinal="m";
                            }


                       }
                    });

            JButton button2 = new JButton("Close");
            button2.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e)
                {
                    dialog.dispose();

                }
       });


            ((AbstractDocument)tField.getDocument()).setDocumentFilter(
                    new MyDocumentFilter());        


            contentPane.add(amountLabel);
            contentPane.add(combo);
            contentPane.add(tField);
            contentPane.add(button); 
            contentPane.add(button2); 

            // JRootPane rootPane = frame.getRootPane(); 
            JRootPane rootPane = dialog.getRootPane();
            rootPane.setDefaultButton(button);

            dialog.pack();
            dialog.setVisible(true);
            dialog.setContentPane(contentPane);
            dialog.setLocationByPlatform(true);

//          frame.setContentPane(contentPane);
//          frame.pack();
//          frame.setLocationByPlatform(true);
//          frame.setVisible(true);
        }

        public static void main(String[] args)
        {
            Runnable runnable = new Runnable()
            {
                @Override
                public void run()
                { 
                    new constraints().displayGUI();
                }
            };
            EventQueue.invokeLater(runnable);
    }
    }

    class MyDocumentFilter extends DocumentFilter
    {   
        @Override
        public void insertString(DocumentFilter.FilterBypass fp
                , int offset, String string, AttributeSet aset)
                                    throws BadLocationException
        {
            int len = string.length();
            boolean isValidInteger = true;

            for (int i = 0; i < len; i++)
            {
                if (!Character.isDigit(string.charAt(i)))
                {
                    isValidInteger = false;
                    break;
                }
            }
            if (isValidInteger)
                super.insertString(fp, offset, string, aset);
            else
                Toolkit.getDefaultToolkit().beep();
        }

        @Override
        public void replace(DocumentFilter.FilterBypass fp, int offset
                        , int length, String string, AttributeSet aset)
                                            throws BadLocationException
        {
            int len = string.length();
            boolean isValidInteger = true;

            for (int i = 0; i < len; i++)
            {
                if (!Character.isDigit(string.charAt(i)))
                {
                    isValidInteger = false;
                    break;
                }
            }
            if (isValidInteger)
                super.replace(fp, offset, length, string, aset);
            else
                Toolkit.getDefaultToolkit().beep();
        }
    }

错误:

Exception in thread "AWT-EventQueue-0" java.awt.IllegalComponentStateException: The window is showing on screen.
    at java.awt.Window.setLocationByPlatform(Unknown Source)
    at constraints.displayGUI(constraints.java:101)
    at constraints.access$1(constraints.java:29)
    at constraints$3.run(constraints.java:116)
    at java.awt.event.InvocationEvent.dispatch(Unknown Source)
    at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
    at java.awt.EventQueue.access$200(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)

Answer 1

您需要使用某种对话框，它将在对话框可见时停止代码执行。

看看How to make dialogs了解更多详情。

此时的基本建议是将 JFrame 更改为 JDialog。确保将其设置为模态。

根据 OP 的更改进行更新

不要忘记使对话框成为模态对话框!

final JDialog dialog = new JDialog();
dialog.setModal(true);
dialog.setDefaultCloseOperation(
                JDialog.DISPOSE_ON_CLOSE);

A Dialog can be modal. When a modal Dialog is visible, it blocks user input to all other windows in the program. JOptionPane creates JDialogs that are modal. To create a non-modal Dialog, you must use the JDialog class directly.

来自 How to make dialogs

虽然稍微高级一点，但您可以看一下 How to use modality in dialogs

根据其他异常(exception)情况进行更新

您打开对话框/窗口的方式有问题。它可能会生成一个大小为 0x0 的窗口。而不是...

dialog.pack();
dialog.setVisible(true);
dialog.setContentPane(contentPane);
dialog.setLocationByPlatform(true);

尝试使用...

dialog.setContentPane(contentPane);
dialog.pack();
dialog.setLocationByPlatform(true);
dialog.setVisible(true);

对代码进行最后一组更改后，对话框将按预期显示...

您可能还希望通读Code Conventions for the Java Programming Language

已更新...

将constraints中的displayGUI方法从private更改为public...

public void displayGUI() {

改变你的“运行者”类别，使其看起来更像......

EventQueue.invokeLater(new Runnable() {
    @Override
    public void run() {
        Constraints constraints = new Constraints();
        constraints.displayGUI();
        System.out.println("Hello world");
    }
});

问题是，constraints main 将构建和显示 UI 的工作传递给事件调度线程(这很好且正确)并立即返回，让调用者代码继续运行。 ..

知道调用链会追捕我...