Question

有人可以告诉我这段代码有什么问题吗？我需要它弹出一个框架并用某个字段填充框架一个名字字段和一个进入字段，并在网格底部显示一个按钮。任何帮助都会受到欢迎，谢谢!!

    import java.awt.*;
    import javax.swing.*;

    public class FrameDemo 
    //To create the gui and show it.
    {   
    public static void createAndShowGUI()
    {
        //create and set up the window.
        JFrame frame = new JFrame("RungeKutta");
        GridLayout first = new GridLayout(1,14);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create, name and Populate TextField   
        JTextField PL = new JTextField("Pendulum Length", 20);
        //Set TextField to Uneditable. Each will have Empty Field Below For Variables   
        PL.setEditable(false);  
        //Set Textfield for user entered dat
        JTextField PLv = new JTextField();
        //Allow handler for user input on Empty Textfield?

        JTextField AD = new JTextField("Angular Displacement", 20);
        AD.setEditable(false);
            JTextField ADv = new JTextField();

        JTextField AV = new JTextField("Angular Velocity", 20);
        AV.setEditable(false);
        JTextField Avv = new JTextField();

        JTextField TS= new JTextField("Time Steps", 20);
        TS.setEditable(false);
        JTextField TSv = new JTextField();

        JTextField MT = new JTextField("Max Time", 20);
        MT.setEditable(false);
        JTextField MTv = new JTextField();

        JTextField V = new JTextField("Viscosity (0-1)", 20);
        V.setEditable(false);
        JTextField Vv = new JTextField();

        //Create Button to Restart
    JButton BNewGraph = new JButton("Draw New Graph"); //Button to restart entire drawing process
        JLabel emptyLabel = new JLabel("");
    emptyLabel.setPreferredSize(new Dimension(600,500));
    frame.getContentPane().add(PL, first);
    frame.getContentPane().add(PLv, first);
    frame.getContentPane().add(AD, first);
    frame.getContentPane().add(ADv, first);
    frame.getContentPane().add(AV, first);
    frame.getContentPane().add(Avv, first);
    frame.getContentPane().add(TS, first);
    frame.getContentPane().add(TSv, first);
    frame.getContentPane().add(MT, first);
    frame.getContentPane().add(MTv, first);
    frame.getContentPane().add(V, first);
    frame.getContentPane().add(Vv, first);
    frame.getContentPane().add(BNewGraph, first);
    //display the window
    frame.pack();
    frame.setVisible(true);
    }

    public static void main(String[] args)
    {
        //add job to event scheduler
        //create and show GUI
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
            }
    }

Answer 1

这不是你使用GridLayout的方式：

frame.getContentPane().add(PL, first);

而是使用布局管理器设置容器的布局：

frame.getContentPane().setLayout(first);

然后将组件添加到容器中：

frame.getContentPane().add(PL);
frame.getContentPane().add(PLv);
frame.getContentPane().add(AD);
frame.getContentPane().add(ADv);
frame.getContentPane().add(AV);
frame.getContentPane().add(Avv);
frame.getContentPane().add(TS);
frame.getContentPane().add(TSv);
frame.getContentPane().add(MT);
frame.getContentPane().add(MTv);
// and so on for all the components.

您需要阅读有关如何使用GridLayout的教程，您可以在此处找到它：GridLayout Tutorial。

顺便说一句，请注意：

frame.getContentPane().add(PL);

可缩短为：

frame.add(PL);

此外，您还需要学习和学习Java命名约定：类名以大写字母开头，所有方法和变量都以小写字母开头。还要避免变量名称，如pl或plv，ad或adv，而是使用更长一点且有意义的名称，这些名称会使代码自我评论。因此，请考虑使用angularDisplacementField作为JTextfield的名称而不是AD。

我自己，我会使用GridBagLayout并执行以下操作：

import java.awt.BorderLayout;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import javax.swing.*;

public class GuiDemo extends JPanel {

   // or better -- use an enum for this
   public static final String[] FIELD_LABELS = {
      "Pendulum Length", "Angular Displacement", "Angular Velocity",
      "Time Steps", "Max Time", "Viscocity (0-1)"
   };
   private static final int TEXT_FIELD_COLUMNS = 10;
   private static final int GAP = 3;
   private static final Insets RIGHT_GAP_INSETS = new Insets(GAP, GAP, GAP, 3 * GAP);
   private static final Insets BALANCED_INSETS = new Insets(GAP, GAP, GAP, GAP);
   private Map<String, JTextField> labelFieldMap = new HashMap<>();

   public GuiDemo() {
      JPanel labelFieldPanel = new JPanel(new GridBagLayout());
      int row = 0;

      // to make sure that no focusAccelerator is re-used
      Set<Character> focusAccelSet = new HashSet<>();
      for (String fieldLabelLText : FIELD_LABELS) {
         JLabel fieldLabel = new JLabel(fieldLabelLText);
         JTextField textField = new JTextField(TEXT_FIELD_COLUMNS);
         labelFieldPanel.add(fieldLabel, getGbc(row, 0));
         labelFieldPanel.add(textField, getGbc(row, 1));
         labelFieldMap.put(fieldLabelLText, textField);

         for (char c : fieldLabelLText.toCharArray()) {
            if (!focusAccelSet.contains(c)) {
               textField.setFocusAccelerator(c);
               fieldLabel.setDisplayedMnemonic(c);
               focusAccelSet.add(c);
               break;
            }
         }

         row++;
      }
      JButton button = new JButton(new DrawGraphAction("Draw New Graph"));

      labelFieldPanel.add(button, getGbc(row, 0, 2, 1));

      setLayout(new BorderLayout(GAP, GAP));
      add(labelFieldPanel, BorderLayout.CENTER);
   }

   private class DrawGraphAction extends AbstractAction {
      public DrawGraphAction(String name) {
         super(name);
         int mnemonic = (int) name.charAt(0);
         putValue(MNEMONIC_KEY, mnemonic);
      }

      @Override
      public void actionPerformed(ActionEvent e) {
         // TODO calculation method

      }
   }

   public static GridBagConstraints getGbc(int row, int column) {
      GridBagConstraints gbc = new GridBagConstraints();
      gbc.gridx = column;
      gbc.gridy = row;
      gbc.gridwidth = 1;
      gbc.gridheight = 1;
      gbc.fill = GridBagConstraints.HORIZONTAL;
      if (column == 0) {
         gbc.anchor = GridBagConstraints.LINE_START;
         gbc.fill = GridBagConstraints.BOTH;
         gbc.insets = RIGHT_GAP_INSETS;
      } else {
         gbc.anchor = GridBagConstraints.LINE_END;
         gbc.fill = GridBagConstraints.HORIZONTAL;
         gbc.insets = BALANCED_INSETS;
      }

      return gbc;
   }

   public static GridBagConstraints getGbc(int row, int column, int width, int height) {
      GridBagConstraints gbc = getGbc(row, column);
      gbc.gridwidth = width;
      gbc.gridheight = height;
      gbc.insets = BALANCED_INSETS;
      gbc.fill = GridBagConstraints.BOTH;
      return gbc;
   }

   private static void createAndShowGui() {
      JFrame frame = new JFrame("Gui Demo");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.getContentPane().add(new GuiDemo());
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

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

JTextField Eclipse中的一切看起来都不错但不会编译

1 个答案: