这是我创建的GUI。
成绩计算器
我不知道您的主要方法在哪里，但是您必须始终通过调用SwingUtilities invokeLater方法来启动Swing应用程序。invokeLater方法将Swing组件的创建和执行放在事件调度线程（EDT）上。
使用GridBagLayout时，我使用创建的addComponent方法为每个Swing组件创建唯一的GridBagConstraints。我不想记住默认值。
Jframe方法的顺序非常重要。在此示例中，记住Jframe方法的顺序。
我把指令放在Jtextarea中。这样，指令文本将根据Jtextarea的大小进行拆分。无需对HTML的换行符进行硬编码。
Here’s the pre.
package com.ggl.testing;import java.awt.Component;import java.awt.Container;import java.awt.GridBagConstraints;import java.awt.GridBagLayout;import java.awt.Insets;import javax.swing.Jframe;import javax.swing.JLabel;import javax.swing.JPanel;import javax.swing.JScrollPane;import javax.swing.Jtextarea;import javax.swing.JTextField;import javax.swing.SwingUtilities;public class GradeAnalysis implements Runnable { private static final Insets normalInsets = new Insets(10, 10, 0, 10); private static final Insets finalInsets = new Insets(10, 10, 10, 10); public static void main(String[] args) { SwingUtilities.invokeLater(new GradeAnalysis()); } @Override public void run() { Jframe frame = new Jframe("Grade Calculator"); frame.setDefaultCloseOperation(Jframe.EXIT_ON_CLOSE); frame.add(createMainPanel()); frame.pack(); frame.setVisible(true); } private JPanel createMainPanel() { GridBagConstraints gbc = new GridBagConstraints(); // Adding the JPanels. Panel for instructions JPanel panel = new JPanel(); panel.setLayout(new GridBagLayout()); int gridy = 0; // JLabel for the Instructions. Jtextarea instructiontextarea = new Jtextarea(5, 30); instructiontextarea.setEditable(false); instructiontextarea.setLineWrap(true); instructiontextarea.setWrapStyleWord(true); instructiontextarea.setText(getInstructions()); JScrollPane instructionScrollPane = new JScrollPane(instructiontextarea); addComponent(panel, instructionScrollPane, 0, gridy++, 3, 1, finalInsets, GridBagConstraints.CENTER, GridBagConstraints.HORIZONTAL); // JLabels for Assignment/Grade/Weight(Percent) JLabel label1 = new JLabel("Assignment"); label1.setHorizontalAlignment(JLabel.CENTER); addComponent(panel, label1, 0, gridy, 1, 1, finalInsets, GridBagConstraints.CENTER, GridBagConstraints.HORIZONTAL); JLabel label2 = new JLabel("Mark"); label2.setHorizontalAlignment(JLabel.CENTER); addComponent(panel, label2, 1, gridy, 1, 1, finalInsets, GridBagConstraints.CENTER, GridBagConstraints.HORIZONTAL); JLabel label3 = new JLabel("Weight"); label3.setHorizontalAlignment(JLabel.CENTER); addComponent(panel, label3, 2, gridy++, 1, 1, finalInsets, GridBagConstraints.CENTER, GridBagConstraints.HORIZONTAL); // JLabel Numbers for the number list of assignments at the side. JLabel number = new JLabel("1"); number.setHorizontalAlignment(JLabel.CENTER); addComponent(panel, number, 0, gridy, 1, 1, normalInsets, GridBagConstraints.CENTER, GridBagConstraints.HORIZONTAL); // JTextfield for Mark JTextField mark = new JTextField(20); mark.setHorizontalAlignment(JLabel.CENTER); addComponent(panel, mark, 1, gridy, 1, 1, normalInsets, GridBagConstraints.CENTER, GridBagConstraints.HORIZONTAL); // JTextfield for Weight JTextField weight = new JTextField(20); weight.setHorizontalAlignment(JLabel.CENTER); addComponent(panel, weight, 2, gridy++, 1, 1, normalInsets, GridBagConstraints.CENTER, GridBagConstraints.HORIZONTAL); return panel; } private String getInstructions() { return "Instructions: Type in the grades you’ve received, along with the weights " + "they’ll have in the determination of your overall average. After you " + "press ‘Calculate’, the results will show your average so far. Every " + "grade you enter must be a non-negative number, and every " + "percentage/weight you enter must be a positive number :)"; } private void addComponent(Container container, Component component, int gridx, int gridy, int gridwidth, int gridheight, Insets insets, int anchor, int fill) { GridBagConstraints gbc = new GridBagConstraints(gridx, gridy, gridwidth, gridheight, 1.0D, 1.0D, anchor, fill, insets, 0, 0); container.add(component, gbc); }}
