Swing 不尊重我的 GridLayout Rows x Columns 定义。怎么修？

Question

我一直在尝试解决这个问题，但没有成功。 如何使JPanel p 尊重定义的GridLayout？ 我得到的只是第一行包含 3 个面板，但不是我告诉 Java 执行的 4 个。

什么是必要的巫术（或我的无知的知识），才能使它起作用？

package temp2;

import java.awt.Dimension;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;


public class Temp2 {

    public static void main(String[] args) {

        JFrame f = new JFrame();
        JPanel p = new JPanel();  
    //  GridLayout flow = new GridLayout(1, 5); --> With this I get a row with 5 jpanels
        GridLayout flow = new GridLayout(2, 4); // --> Why it doenst work? I want 4 
                                                // jpanels in the first row and 
                                                // subsequent one on the next row
                                                // --> Why it doesnt respect my code?
        p.setLayout(flow);
      // p.setSize(800,800); // --> This doesnt make any difference on final result either
      //  p.setPreferredSize(new Dimension(800,800));  // --> This doesnt make any
                                                      // difference on final result either
        p.setMinimumSize(new Dimension(800,800));

        JPanel x1 = new JPanel();     
        x1.setPreferredSize(new Dimension(50,30)); // --> It doesnt respect these preferences
        x1.setMaximumSize(new Dimension(50,30)); // --> It doesnt respect this maximum
        x1.setBorder(javax.swing.BorderFactory.createEtchedBorder());

        JPanel x2 = new JPanel();       
        x2.setPreferredSize(new Dimension(50,30)); // --> It doesnt respect these preferences
        x2.setMaximumSize(new Dimension(50,30)); // --> It doesnt respect this maximum
        x2.setBorder(javax.swing.BorderFactory.createEtchedBorder());

        JPanel x3 = new JPanel();      
        x3.setPreferredSize(new Dimension(50,30)); // --> It doesnt respect these preferences
        x3.setMaximumSize(new Dimension(50,30)); // --> It doesnt respect this maximum
        x3.setBorder(javax.swing.BorderFactory.createEtchedBorder());

        JPanel x4 = new JPanel();      
        x4.setPreferredSize(new Dimension(50,30)); // --> It doesnt respect these preferences
        x4.setMaximumSize(new Dimension(50,30));  // --> It doesnt respect this maximum      
        x4.setBorder(javax.swing.BorderFactory.createEtchedBorder());

        JPanel x5 = new JPanel();       
        x4.setMaximumSize(new Dimension(50,30)); // --> It doesnt respect these preferences
        x5.setPreferredSize(new Dimension(50,30)); // --> It doesnt respect this maximum 
        x5.setBorder(javax.swing.BorderFactory.createEtchedBorder());

         p.add(x1);
         p.add(x2);
         p.add(x3);
         p.add(x4);
         p.add(x5);

         f.getContentPane().add(p, "Center");

         f.setSize(800, 800);
         f.setVisible(true);
         p.updateUI();

        }   
    }

因为这是我的第一个 StackOverflow 问题，所以我试图严格遵守规则：

具体：我希望GridLayout 尊重行 x 列的定义

我的最终目的是什么：在第一行显示 4 个面板，在第二行显示后续一个。

使其与他人相关：这就是为什么此代码具有指导意义，重复所有小组声明，以便新手（和我）能够理解所有代码并专注于 GridLayout 问题。

Answer 1

    GridLayout flow = new GridLayout(2, 4); // --> Why it doenst work? I want 4 
                                            // jpanels in the first row and 
                                            // subsequent one on the next row
                                            // --> Why it doesnt respect my code?

像这样？

改用：

    GridLayout flow = new GridLayout(0,4);

引用constructor 的文档：

创建具有指定行数和列数的网格布局。布局中的所有组件都具有相同的大小。

行和列中的一个（但不能同时）可以为零，这意味着可以将任意数量的对象放在一行或一列中。