这个项目的目标是创建四个类：Student类，GradStudent类，Manager类和GUI类。在GUI中有两个单选按钮：一个用于学生，一个用于GradStudent。根据选择的是哪一个，Manager类应该负责通过使用两个数组来创建和存储Student或GradStudent对象。我还在我的GUI中添加了一个按钮，该按钮应该将Student数组打印到JTextArea，但这是我遇到问题的地方。我得到错误＆＃34;无法在基本类型int＆＃34;上调用toString（）。我明白为什么会这样，但我不知道如何解决这个问题。任何帮助将不胜感激。谢谢！
GUI类
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.JRadioButton;
import javax.swing.ButtonGroup;
public class GUI extends JFrame {
private JRadioButton jrbStudent = new JRadioButton("Student");
private JRadioButton jrbGraduate = new JRadioButton("Graduate");
private JTextField name = new JTextField(20);
private JTextField address = new JTextField(20);
private JTextField balance = new JTextField(20);
private JTextField major = new JTextField(20);
private JButton jbtSubmit = new JButton("Submit");
private JTextArea echoStudent = new JTextArea();
private JButton printStudentNames = new JButton("Print Student's Names");
private JButton printGradStudentNames = new JButton(
"Print Graduate Student's Names");
private JButton calcBalance = new JButton(
"Calculate Average Balance of All Students");
private JButton compSciMajor = new JButton(
"Displays Computer Science Major Students");
private Manager m1 = new Manager();
public GUI() {
// Creates panel P1 and adds the components
JPanel p1 = new JPanel(new GridLayout(9, 1, 10, 10));
p1.add(new JLabel("Name: "));
p1.add(name);
p1.add(new JLabel("Address: "));
p1.add(address);
p1.add(new JLabel("Balance: "));
p1.add(balance);
p1.add(new JLabel("Major: "));
p1.add(major);
p1.add(jrbStudent);
p1.add(jrbGraduate);
p1.add(new JLabel("Submit Button: "));
p1.add(jbtSubmit);
p1.add(printStudentNames);
p1.add(printGradStudentNames);
p1.add(calcBalance);
p1.add(compSciMajor);
p1.add(new JLabel("Submitted Text: "));
// Creates a radio-button group to group both buttons
ButtonGroup group = new ButtonGroup();
group.add(jrbStudent);
group.add(jrbGraduate);
// Adds the panel and text area to the frame
add(p1);
p1.add(echoStudent);
echoStudent.setEditable(false);
// Creates a listener and registers it with the submit button
SubmitListener l1 = new SubmitListener();
jbtSubmit.addActionListener(l1);
// Creates a listener and registers it with the radio buttons
JRBListener l2 = new JRBListener();
jrbStudent.addActionListener(l2);
jrbGraduate.addActionListener(l2);
// Creates a listener and registers it with the PrintStudentNames button
StudentListener l3 = new StudentListener();
printStudentNames.addActionListener(l3);
}
// Class to handle the submit button
class SubmitListener implements ActionListener {
public void actionPerformed(ActionEvent a) {
Student[] students = new Student[50];
int arrayLocation = 0;
Student student1 = new Student(name.getText(), address.getText(),
balance.getText(), major.getText());
// Checks remaining array space
if (arrayLocation < 50) {
students[arrayLocation] = student1;
++arrayLocation;
}
// Echos back entered text while storing the previous text
echoStudent.setText(echoStudent.getText() + "\n"
+ student1.toString());
}
}
// Class to handle the radio buttons
class JRBListener implements ActionListener {
public void actionPerformed(ActionEvent b) {
if (b.getSource() == jrbStudent) {
m1.addStudent(name.getText(), address.getText(),
balance.getText(), major.getText());
echoStudent
.setText("Created Student: \n" + m1.getLastStudent());
}
if (jrbGraduate.isSelected()) {
m1.addGradStudent(name.getText(), address.getText(),
balance.getText(), major.getText());
echoStudent.setText("Created Graduate Student: \n"
+ m1.getLastGradStudent());
}
}
}
class StudentListener extends Manager implements ActionListener {
public void actionPerformed(ActionEvent c) {
echoStudent.setText(counter1.toString());
}
}
public static void main(String[] args) {
GUI frame = new GUI();
frame.setTitle("Information Interface");
frame.setSize(1200, 900);
frame.setLocationRelativeTo(null); // Center the frame
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
经理类
public class Manager {
public Student[] students = new Student[50];
public int counter1 = 0;
private GradStudent[] gradStudents = new GradStudent[50];
private int counter2 = 0;
public Manager() {
}
public void addStudent(String name, String address, String balance, String major) {
Student student1 = new Student(name, address, balance, major);
students[counter1] = student1;
counter1++;
}
public String getLastStudent() {
return "Student added: " + students[counter1-1] +"\n";
}
public void addGradStudent(String name, String address, String balance, String major) {
GradStudent student2 = new GradStudent(name, address, balance, major);
gradStudents[counter2] = student2;
counter2++;
}
public String getLastGradStudent() {
return "Graduate Student added: " + gradStudents[counter2-1] +"\n";
}
}
答案 0 :(得分：2)
无法在基本类型int
上调用toString（）
使用
Integer.toString(counter1);
答案 1 :(得分：1)
您也可以尝试将此int转换为String
String.valueOf(counter1);
或者您也可以尝试Integer课程
new Integer(counter1).toString();
或使用
Integer.valueOf(counter1).toString();
- 编辑 -
根据您上次的评论，这里是打印JTextArea
class StudentListener extends Manager implements ActionListener {
public void actionPerformed(ActionEvent c) {
StringBuilder builder=new StringBuilder();
for(int i=0;i<counter1;i++){
builder.append(m1.students[i].name);
}
echoStudent.setText(builder.toString());
}
}