用Java Swing点击JButton打开新的JFrame

Question

我尝试通过按钮点击事件打开一个新的JFrame窗口。这个网站上有很多信息，但都没有帮助我，因为我认为不是我的代码问题，而是它执行的顺序（但我不确定）。

这是包含我想要启动事件的按钮的框架的代码：

package messing with swing;

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import javax.swing.border.EmptyBorder;


public class ReportGUI extends JFrame{
    //Fields
    private JButton viewAllReports = new JButton("View All Program Details");
    private JButton viewPrograms = new JButton("View Programs and Majors Associated with this course"); 
    private JButton viewTaughtCourses = new JButton("View Courses this Examiner Teaches"); 
    private JLabel courseLabel = new JLabel("Select a Course: ");
    private JLabel examinerLabel = new JLabel("Select an Examiner: "); 
    private JPanel panel = new JPanel(new GridLayout(6,2,4,4));  
    private ArrayList<String> list = new ArrayList<String>(); 
    private ArrayList<String> courseList = new ArrayList<String>();  


     public ReportGUI(){   
           reportInterface();
           allReportsBtn();     
           examinnerFileRead();
           courseFileRead();
           comboBoxes();
     }        

     private void examinnerFileRead(){
         try{
             Scanner scan = new Scanner(new File("Examiner.txt"));

             while(scan.hasNextLine()){
                 list.add(scan.nextLine());
             }
             scan.close();
         }
         catch (FileNotFoundException e){
             e.printStackTrace();
         }
     }
      private void courseFileRead(){
         try{
             Scanner scan = new Scanner(new File("Course.txt"));

             while(scan.hasNextLine()){
                 courseList.add(scan.nextLine());
             }
             scan.close();
         }
         catch (FileNotFoundException e){
             e.printStackTrace();
         }
     }

    private void reportInterface(){         
          setTitle("Choose Report Specifications");                   
          setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
          JPanel panel = new JPanel(new FlowLayout());        
          add(panel, BorderLayout.CENTER);
          setSize(650,200);
          setVisible(true);    
          setResizable(false);
          setLocationRelativeTo(null);
}    
    private void allReportsBtn(){
        JPanel panel = new JPanel(new GridLayout(1,1)); 
        panel.setBorder(new EmptyBorder(70, 50, 70, 25));
        panel.add(viewAllReports);        
        viewAllReports.addActionListener(new ActionListener(){
            @Override
            public void actionPerformed(ActionEvent e){
                JFrame AllDataGUI = new JFrame();
                new AllDataGUI();
            }
        });         
        add(panel, BorderLayout.LINE_END);
    }       
    private void comboBoxes(){                
        panel.setBorder(new EmptyBorder(0, 5, 5, 10));
        String[] comboBox1Array = list.toArray(new String[list.size()]);
        JComboBox comboBox1 = new JComboBox(comboBox1Array);          
        panel.add(examinerLabel);
        panel.add(comboBox1);          
        panel.add(viewTaughtCourses);
         viewTaughtCourses.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {                 
                JFrame ViewCourseGUI = new JFrame();
                new ViewCourseGUI();
            }
        });  
         String[] comboBox2Array = courseList.toArray(new String[courseList.size()]);
         JComboBox comboBox2 = new JComboBox(comboBox2Array);
         panel.add(courseLabel);         
         panel.add(comboBox2); 
         panel.add(viewPrograms);
         add(panel, BorderLayout.LINE_START); 

    } 

如果您不想深入了解上面的代码，这里是按钮ActionListener：

 panel.add(viewTaughtCourses);
             viewTaughtCourses.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {                 
                    JFrame ViewCourseGUI = new JFrame();
                    new ViewCourseGUI();
                }
            });  

这是我想要打开的JFrame所在类中的代码：

在这里放置了JFrame的代码：

package messing with swing;

import java.awt.BorderLayout;
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.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.border.EmptyBorder;


public class ViewCourseGUI extends JFrame{ 
    private JButton saveCloseBtn = new JButton("Save Changes and Close");
    private JButton closeButton = new JButton("Exit Without Saving");
    private JFrame frame=new JFrame("Courses taught by this examiner");
    private JTextArea textArea = new JTextArea();



     public void ViewCoursesGUI(){
         panels();
     }        

    private void panels(){        
          JPanel panel = new JPanel(new GridLayout(1,1));
          panel.setBorder(new EmptyBorder(5, 5, 5, 5));
          JPanel rightPanel = new JPanel(new GridLayout(15,0,10,10));
          rightPanel.setBorder(new EmptyBorder(15, 5, 5, 10));
          JScrollPane scrollBarForTextArea=new JScrollPane(textArea,JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
          panel.add(scrollBarForTextArea); 
          frame.add(panel);
          frame.getContentPane().add(rightPanel,BorderLayout.EAST);
          rightPanel.add(saveCloseBtn);
          rightPanel.add(closeButton);

           frame.setSize(1000, 700);
           frame.setVisible(true);   
           frame.setLocationRelativeTo(null);

}
}

请问有人能指引我正确的方向吗？

- Splunk

---

我不知道你为什么要把viewCourseGUI设置为一个新的JFrame。请这样做：JFrame ViewCourseGUI = new ViewCourseGUI(); - Sesame

我会试一下。我也不确定，还在学习这些微小的差别。 - Splunk

public void ViewCoursesGUI() 不是构造函数，因此在使用 new 关键字时不会被调用。请移除 void。构造函数不能有任何声明的返回类型，包括 void。 - PM 77-1

结合我将它命名为ViewCoursesGUI()而不是ViewCourseGUI()的事实...现在它可以工作了。非常感谢。 - Splunk

请查看使用多个JFrames，好的/坏的做法？。 - Andrew Thompson

Answer 1

在 actionListener 中将要打开的 JFrame 的可见性设置为 true：

ViewCourseGUI viewCourseGUI = new ViewCourseGUI();
viewCourseGUI.setVisible(true);

点击按钮后，这将打开新的JFrame窗口。

- Saba Jamalian

Answer 2

如PM 77-3所指出的

我有：

 public void ViewCoursesGUI(){
     panels();
 }        

当我应该有：

public ViewCourseGUI(){
     panels();
 }        

一个由语法和拼写错误组成的组合。

- Splunk

---

也可以查看使用多个JFrames是好还是坏的实践，这真的很有趣。 - Frakcool

你在使用集成开发环境吗？ - David Yee

Answer 3

让ReportGUI实现ActionListener。然后你将为按钮点击实现actionPerformed。在按钮点击时，创建第二个框架（如果它不存在）。最后，设置第二个框架可见（如果它当前不可见）：

import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;

public class ReportGUI  extends JFrame implements ActionListener {
    private static final long serialVersionUID = 8679886300517958494L;

    private JButton button;
    private ViewCourseGUI frame2 = null;

    public ReportGUI() {

        //frame1 stuff
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(300,200);
        setLayout(new FlowLayout());

        //create button
        button = new JButton("Open other frame");
        button.addActionListener(this);
        add(button);

    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    ReportGUI  frame = new ReportGUI();
                    frame.setVisible(true);

                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == button) {
            if (frame2 == null)
                frame2 = new ViewCourseGUI();
            if (!frame2.isVisible())
                frame2.setVisible(true);
        }

    }

}

这是一个简单的例子。你需要在这里添加你的其余代码。

- Edwin Torres