Java Swing从子对话框访问父数据 [英] Java Swing accesing parent data from child dialog

问题描述

我使JFrame成为父级，而Jdialog成为子级.但是我无法访问变量的修改后的值
子类中的父项.代码:

I made a JFrame parent and Jdialog child. But I am not able to access the modified value of the variable
of parent from the child class. code:

import [swing packages needed];

public class grading extends JFrame implements ActionListener
{
	public int me=4; //this one
	JTextField jt;

grading()
{
	Container c=getContentPane();
	// set the layout

	jt=new JTextField(30);
	jt.addActionListener(this);
	c.add(jt);

	setSize(800,600);
	show();

}

public void actionPerformed(ActionEvent a) // pressed enter key in the textfield
{
	me=2; //changed me value

	JOptionPane.showMessageDialog(null,(me)+" is me from parent"); //displayed : 2

	child jd=new child(this); //calls dialog
	jd.setVisible(true);
	}

public static void main(String ar[])
{
	grading Gr=new grading();
	//close window handling 
}

}


class child extends JDialog
{
	JTextField jta[];

child(JFrame frame)
{
	super(frame,true);
	Container c=getContentPane();
	c.setLayout(new FlowLayout());

	grading gr=new grading();
	JOptionPane.showMessageDialog(null,(gr.me)+" is me from child"); //shows 4

	setSize(400,300);
	setDefaultCloseOperation(DISPOSE_ON_CLOSE);
}
}

推荐答案

您正在子类中创建第二个评分，而不是访问父类.

尝试更换线路:

You''re creating a second grading in the child class, rather than accessing the parent class.

Try replacing the lines:

grading gr=new grading();
JOptionPane.showMessageDialog(null,(gr.me)+" is me from child"); //shows 4

与

with

JOptionPane.showMessageDialog(null,(frame.me)+" is me from child");

这篇关于Java Swing从子对话框访问父数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！