用户输入会导致frame.getContentPane.removeAll（）停止工作 [英] User input causes frame.getContentPane.removeAll() to stop working

问题描述

在JFrame中，我正在用另一个JPanel替换Jpanel。

Within a JFrame , i am replacing a Jpanel with another JPanel .

package testing;

import java.io.*;
import java.util.*;
import java.security.*;
import javax.xml.bind.DatatypeConverter;
import java.lang.*;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;


public class Testing extends JPanel {

    JLabel jl;
    ImageIcon icon;
    Point pointer;


    public static void main(String[] args) {

       JFrame jf = new JFrame();

       JPanel jp1 = new JPanel();
       JPanel jp2 = new JPanel();

       JLabel jl1 = new JLabel("Hey1");
       JLabel jl2 = new JLabel("Hey2");

       jp1.add(jl1);
       jp2.add(jl2);

       jf.add(jp1);

       jf.setVisible(true);
       jf.pack();

       Scanner myScanner= new Scanner(System.in);

       int x = myScanner.nextInt(); // the line causes the code to not work , 

                                    //    what is happening

       jf.getContentPane().removeAll();

       jf.add(jp2);


    }
}

奇怪的部分是代码停止工作的时候我试图读取用户输入

The weird part is that the code stops working the moment i try to read user input

int x = myScanner.nextInt（）;

int x = myScanner.nextInt();

代码： jf.getContentPane（）。removeAll（）; 停止工作，我不能删除目前的JPanel并添加了新的JPanel

The code : jf.getContentPane().removeAll(); stops working and i cant remove the current JPanel and add in the new JPanel

我需要在JPanel替换之前阅读用户输入，我如何解决这个问题？

i need to read in the user input before the JPanel is replaced , how do i resolve this issue??

注意：即使我输入内容，jf.getContentPane（）。removeAll（）仍然无效

推荐答案

使用 validate（）布局容器的子组件。另外 pack（） 窗口 之前
setVisible（）。

Use validate() to layout the container's subcomponents. Also pack() the Window before setVisible().

或者，使用 CardLayout 更改视图和 JTextField 来收集用户输入。

Alternatively, use CardLayout to change the view and JTextField to collect user input.

如测试：

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

public class Testing extends JPanel {

    JLabel jl;
    ImageIcon icon;
    Point pointer;

    public static void main(String[] args) {
        JFrame jf = new JFrame();
        jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JPanel jp1 = new JPanel();
        JPanel jp2 = new JPanel();
        JLabel jl1 = new JLabel("Hey1");
        JLabel jl2 = new JLabel("Hey2");
        jp1.add(jl1);
        jp2.add(jl2);
        jf.add(jp1);
        jf.pack();
        jf.setVisible(true);
        Scanner myScanner = new Scanner(System.in);
        int x = myScanner.nextInt(); // the line causes the code to not work , 
        jf.getContentPane().removeAll();
        jf.add(jp2);
        jf.validate();
    }
}

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