单击JButton时发生错误-未执行ActionEvent

Question

Here I have a GUI window and it basically ask the user to select a JRadioButton and type something in a JTextField, then choose confirm/cancel.

It is a project which we have to make a UML-to-Java text file. User would enter class information and choose a UML relationship, and this programme have to print out the Java clsas text on a JTextField. Just like when you create a new class in eclipse.

what I want to do is make a boolean[] to store an array of booleans, when user selects JRadioButton_A it'll store true and when user select JRadioButton_B it'll store false.And also I want the things typed in JTextField to be checked by a checkName(), if the method returns false, the string will be stored in an ArrayList<String> .

Below is my code - and the error is that when user clicked confirmButton, the programme just stopped and have no reaction. Also, there's some problems in getName() method and the boolean[] for storing true and false. When user needs to input name again, it would save the discarded sting/boolean into the array. Is there any better way to make this programme? I feel like I am complicating things and there should be a simpler way to make it.

Here's my UI class

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

public class AddClass extends JFrame{
Scanner input = new Scanner(System.in);
ClassName classObject = new ClassName();

private JRadioButton publicButton, privateButton;
private JLabel className;
private JTextField inputClassName;
private JButton confirmButton;
private JButton cancelButton;

public AddClass(){
    super("Add class");
    setLayout(new FlowLayout());

    publicButton = new JRadioButton("public", true);
    privateButton = new JRadioButton("private", false);
    className = new JLabel("Class Name: ");
    inputClassName = new JTextField(10);
    confirmButton = new JButton("Confirm");
    cancelButton = new JButton("Cancel");

    add(publicButton);      
    add(privateButton);     
    add(className);     
    add(inputClassName);        
    add(confirmButton);
    add(cancelButton);

    ButtonGroup group = new ButtonGroup();
    group.add(publicButton);
    group.add(privateButton);

    Handler handler = new Handler();
//      Handler2 handler2 = new Handler2();     
//      Handler3 handler3 = new Handler3();
    confirmButton.addActionListener(handler);
//      publicButton.addActionListener(handler2);
//      privateButton.addActionListener(handler3);
    }// end constructor AddClass()

private class Handler implements ActionListener{
    public void actionPerformed(ActionEvent event){
        String name = inputClassName.getText();
        classObject.addName(name);
        while (classObject.checkName(name) == true){
            JOptionPane.showMessageDialog(null, "Class name invalid. " +
                    "\nEntered name should not contain java keywords or equal to other existing names. " +
                    "\nPlease try again."); // doesn't work
            name = input.nextLine();
            classObject.addName(name);
        }// end if
        JOptionPane.showMessageDialog(null, "Class saved."); // doesn't work
        name = input.nextLine();
        classObject.addName(name);

    }// end actionPerformed()
}// end Handler class

private class Handler2 implements ActionListener{
    public void actionPerformed(ActionEvent event){
        boolean b = true;
        b = classObject.setPP();
        }
    }

private class Handler3 implements ActionListener{
    public void actionPerformed(ActionEvent event){
        boolean b = false;
        b = classObject.setPP();
        }
    }


}// end AddClass

Here's my class for storing user input

import java.util.Scanner;
import java.util.ArrayList;

public class ClassName {
Scanner input = new Scanner(System.in);
JavaKeywords keyObject = new JavaKeywords();

private ArrayList<String> className = new ArrayList<String>();
private String name = new String();
private int size = className.size();
private Boolean[] bArray = new Boolean[size];

public void addName(String name){
    this.name = name;
    className.add(name);
}// end addName()

public boolean checkName(String name){
    boolean check = true;
    for (int i=0; i<=size; i++){
        if (keyObject.containsKeyword(className.get(i)) || name.equals(className.get(i))){

            boolean o = false;
            check = o;
        }// end if
    }// end for
    return check;
}// end checkName

public boolean setPP(){
    boolean b = true;
    return b;
}

public void addPP(Boolean[] bArray){
    this.bArray = bArray;
    for (int i=0; i>=size; i++){
        bArray[i] = setPP();
    }
}// add a Array of boolean. for className[i], its class type = item[i] in bArray. 
             // public = true, private = false
public String getPublicPrivate(){
    String p = "";
    for (int i =0; i<=size; i++){
        if(bArray[i]=true)
            p = "public";
        else
            p = "private";
    }
    return p;
}

public void setName(String name){
    this.name = name;
}//end setName()

public String getName(){
    return name;
}// end getName()

public ArrayList<String> getAllNames(){
    return className;
}// end getAllNames()

public void setAllNames(ArrayList<String> className){
    this.className = className;
}// end setAllNames()

}//end class

Answer 1

In the ActionListener for the confirm button the Scanner instance input in this statement blocks waiting on input from the user

String name = input.nextLine();

The ActionEvent won't complete until a value has been entered.

Solution: Add a JTextField as an alternative means to read input from the user.

Answer 2

The reason your program "stops" when the user clicks the confirm button is that the program is waiting for input on the command line. Specifically, your input variable is tied to System.in (ie command line).

You can just type your answer at the command line, hit Enter nad your program will continue.

OTOH, I suspect that using the command line is not what you want as you are using a GUI. Instead you can add an input field (eg a JTextBox).