Question

我有一个名为TabBuilder的类，我用它来创建我的应用程序的界面，但我遇到了一个奇怪的问题。如果我尝试运行下面的代码，它将绘制主屏幕，但如果我从BarMenu请求SearchScreen它不会显示。如果我尝试在public static void main (String[] args) MainString中仅自己执行SearchScreen（调用它的构建器），它也不会出现。但如果转到请求事件并提示TabBuilder tb = new TabBuilder(); tb.requestTab();，屏幕将显示为应该显示的内容。那么，可能出现什么问题？提前致谢

MainScreen：

public class MainScreen{

    public MainScreen()
    {
        TabBuilder tb = new TabBuilder();
        tb.mainTab();   
  }
}

SearchScreen：

public class SearchScreen{

    public void SearchScreen(){

        TabBuilder tb = new TabBuilder();
        tb.requestTab();        

    }
}

TabBuilder：

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

public class TabBuilder implements ActionListener {

    JTabbedPane tabbedPane = new JTabbedPane();
    JMenuItem close, request;
    protected JTextField txtrequest = new JTextField();
    JButton btrequest = new JButton();
    protected JFrame requestFrame = new JFrame();

    public void TabBuilder(){

    }

    public void mainTab(){

        JMenuBar bar;
        JMenu file, register;
        JFrame mainFrame = new JFrame();

        bar= new JMenuBar();
        file= new JMenu("File");
        register= new JMenu("Request");

        close= new JMenuItem("Close");
        close.addActionListener(this);

        request= new JMenuItem("Request Query");
        request.addActionListener(this);

        bar.add(file);
        bar.add(register);
        file.add(close);
        register.add(request);

        mainFrame.setExtendedState(mainFrame.getExtendedState() | mainFrame.MAXIMIZED_BOTH); // Maximized Window or setSize(getMaximumSize());
        mainFrame.setTitle("SHST");
        mainFrame.setJMenuBar(bar);
                        mainFrame.setDefaultCloseOperation(0);
        mainFrame.setVisible(true);

        WindowListener J=new WindowAdapter(){
            public void windowClosing(WindowEvent e){
                System.exit(0);
            }
        }; 

        mainFrame.addWindowListener(J);
    }

    public void requestTab(){
        JLabel lbrequest;
        JPanel requestPane;

        btrequest= new JButton("request");
        lbrequest= new JLabel("Type Keywords in english to be requested below:");
        txtrequest= new JTextField();
        requestPane=new JPanel();
        requestPane.setBackground(Color.gray);
        requestPane.add(lbrequest);
        requestPane.add(txtrequest);
        requestPane.add(btrequest);
        requestPane.setLayout(new GridLayout(3,3));
        btrequest.setEnabled(true);

        requestFrame.add(requestPane);
        requestFrame.setTitle("SHST");
        requestFrame.setSize(400, 400);
        requestFrame.setVisible(true);
        requestFrame.setDefaultCloseOperation(1);
    }

    public void actionPerformed(ActionEvent e){
        if(e.getSource()==close){
            System.exit(0);
        }

        if(e.getSource()==request){
            TabBuilder tb = new TabBuilder();
            tb.requestTab();
        }
    } 

    public static void main (String[] args){
        MainScreen m = new MainScreen();
    }
}

Answer 1

SearchScreen的构造函数已确定为void。这导致在调用构造函数时没有返回任何对象。新手失败但简单的解决方案。

JFrame没有显示出来

1 个答案: