JPanel在使用无效、验证和重新绘制时不更新

Question

我有一个问题，我的一个JPanels没有根据窗口更新自己，而它应该也是。我将试着简要地解释一下发生了什么。将一个字符列表从另一个类输入到arraylist（名为lookReply）中（这与我测试的一样有效），然后使用2 iterations将每个字符分配给由JLabels制成的方形表中的一个坐标。这些JLabels位于lookReplyGUIPanel JPanel中。按下按钮后，新字符将加载到arraylist中，并重复执行。但是，该窗口不会显示此更新。我知道他们通过一些测试被输入到JLabels中，但只是窗口的更新似乎不起作用。我正在使用invalidate, validate and repaint，但它仍然不起作用。请参阅我下面的代码以获取所需的零件。

第一个方法-处理arraylist，然后调用另一个方法。

private void look()
{
    //clear arrayList then add new lookReply to it
    lookReply.clear();
    while (HumanUser.lookReply==null)
    {
    }
    for(int n = 0; n<HumanUser.lookReply.length(); n++)
    {
        lookReply.add(HumanUser.lookReply.charAt(n));                   
    }
    lookReply();
//UP TO HERE WORKS FINE
    screen.invalidate();
    screen.validate();
    screen.repaint();
}

处理所讨论的CCD_ 10的方法。

/**
 * Made up of several smaller JPanels each relate to 1 map position from the lookReply command.
 */
private JPanel lookReply()
{
    JPanel lookReplyGUIPanel = new JPanel(new GridBagLayout());
    GridBagConstraints c = new GridBagConstraints();
    Border blackline = BorderFactory.createLineBorder(Color.black);

    //Create a square table dependent on the radius of view.
    //Then fill each cell with the block retrieved from the lookReply arrayList.
    for(int y = lookReplyY; y>0; y--)
    {
        for(int x = lookReplyX; x>0; x--)
        {wall...
            //Then assign it to a variable which is used in the JLabel.
            String item = null;
            if (lookReply.size()!=0)
            {
                item = lookReply.get(x*y-1) + "";
            }
            //ADD TO CHECK WHAT EACH ITEM IS AND USE THE RELEVENT PICTURE
            JLabel lookx = new JLabel(item);
            int width = (2*screenHeight/(5*lookReplyX)-10);
            lookx.setPreferredSize(new Dimension(width, width));
            lookx.setBorder(blackline);
            c.gridx = x;
            c.gridy = y;
            lookReplyGUIPanel.add(lookx, c);
        }
    }
    return lookReplyGUIPanel;
}

如果这有帮助的话，请提供更多关于一切概述的详细信息。调用的第一个方法使用gridBagConstraints将所有JPanels添加到正确位置的JFrame。JFrame是在一个方法之外创建的，所以所有其他方法都可以看到它。非常感谢所有帮助，如果需要，很乐意提供更多细节！感谢

下面是一段简单的可编译代码，它演示了同样的问题。忽略必须调整窗口大小的事实-每次单击button按钮都会将m增加1，并且应该更新以显示5X5 m表的lookReply方法。但事实并非如此。

import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class temp
{
JFrame screen = new JFrame("temp");
int m = 1;

public static void main(String[] args)
{
    temp g = new temp();
    g.create();
}
private void create()
{       
    screen.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    screen.setLayout(new GridBagLayout());
    GridBagConstraints c = new GridBagConstraints();
    c.gridy = 0;
    screen.add(lookReply(), c);

    c.gridy = 1;
    screen.add(button(), c);
    screen.setVisible(true);
}
private JPanel lookReply()
{
    JPanel lookReplyGUIPanel = new JPanel(new GridBagLayout());
    GridBagConstraints c = new GridBagConstraints();
    for(int y = 5; y>0; y--)
    {
        for(int x = 5; x>0; x--)
        {
            JLabel lookx = new JLabel((m + ""));
            c.gridx = x;
            c.gridy = y;
            lookReplyGUIPanel.add(lookx, c);
        }
    }
    screen.invalidate();
    screen.validate();
    screen.repaint();
    return lookReplyGUIPanel;
}
private JPanel button()
{
    JPanel button = new JPanel(new GridBagLayout());
    GridBagConstraints c = new GridBagConstraints();
    JButton b = new JButton("button");
    b.setBorder(null);
    c.gridx = 2;
    c.gridy = 2;
    button.add(b, c);
    b.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            m++;
            lookReply();                
        }
    });
    return button;
}

}

Answer 1

因此，根据您的示例，lookReply创建了一个新的JPanel，但您没有对它做任何操作。因此，该组件从未添加到屏幕上，因此所有使其刷新的尝试都不会产生任何效果。。。

Answer 2

使用javax.swing.Timer更新GUI元素，如下所示。