java GridLayout中JPanels之间的间隙

Gap between JPanels in GridLayout

提问by Paul

The code below produces nine individual JPanels in which are 9 buttons. The nine JPanels are arranged onto a base JPanel using GridLayout. This base JPanel is then placed onto the ContentPane using Border Layout. I'm using borders for the JButtons and each individual JPanel to clearly define their separation. The JButtons inside each JPanel look fine but there is a gap between the JPanels which is causing the appearance of a double line which is bugging the hell out of me. I've tried adding each individual JPanel onto the ContentPane directly but this does nothing. Totally stumped and wondering if anyone has any suggestions?

下面的代码生成了 9 个单独的 JPanel，其中有 9 个按钮。使用 GridLayout 将九个 JPanel 排列到基本 JPanel 上。然后使用边框布局将此基本 JPanel 放置到 ContentPane 上。我为 JButton 和每个单独的 JPanel 使用边框来明确定义它们的分隔。每个 JPanel 内的 JButton 看起来不错，但 JPanel 之间存在间隙，这导致出现双线，这让我很烦。我试过将每个单独的 JPanel 直接添加到 ContentPane 上，但这没有任何作用。完全被难住了，想知道是否有人有任何建议？

P.S. I know the mass of duplicate code needs re-factoring in a bad way and it will, this is just for mock-up purposes.

PS 我知道大量的重复代码需要以一种糟糕的方式重构，它会的，这只是为了模拟目的。

Thanks,

谢谢，

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

public class View1 extends JFrame
{
    private JPanel      basePanel;
    private JPanel      childPanel1;
    private JPanel      childPanel2;
    private JPanel      childPanel3;
    private JPanel      childPanel4;
    private JPanel      childPanel5;
    private JPanel      childPanel6;
    private JPanel      childPanel7;
    private JPanel      childPanel8;
    private JPanel      childPanel9;
    private int         row = 3;
    private int         column = 3;
    private JButton[][] squares1;
    private JButton[][] squares2;
    private JButton[][] squares3;
    private JButton[][] squares4;
    private JButton[][] squares5;
    private JButton[][] squares6;
    private JButton[][] squares7;
    private JButton[][] squares8;
    private JButton[][] squares9;
    private Font        numberFont;

public View1()
{
    setSize(400,400);
    setTitle("2013");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    basePanel  = new JPanel();
    basePanel.setLayout(new GridLayout(row, column, 0, 0));
    numberFont = new Font("sansserif", Font.BOLD, 32);

    childPanel1Setup();
    childPanel2Setup();
    childPanel3Setup();
    childPanel4Setup();
    childPanel5Setup();
    childPanel6Setup();
    childPanel7Setup();
    childPanel8Setup();
    childPanel9Setup();

    basePanel.add(childPanel1);
    basePanel.add(childPanel2);
    basePanel.add(childPanel3);
    basePanel.add(childPanel4);
    basePanel.add(childPanel5);
    basePanel.add(childPanel6);
    basePanel.add(childPanel7);
    basePanel.add(childPanel8);
    basePanel.add(childPanel9);

    Container cp = getContentPane();
    cp.setLayout(new BorderLayout());
    cp.add(basePanel, BorderLayout.CENTER);
}

public void childPanel1Setup()
{
    childPanel1 = new JPanel();
    childPanel1.setLayout(new GridLayout(row, column, 0, 0));
    childPanel1.setBorder(BorderFactory.createLineBorder(Color.BLACK));
    squares1 = new JButton[row][column];

    for(int rows = 0; rows < this.row; rows++)
    {
        for(int cols = 0; cols < this.column; cols++)
        {
            squares1[rows][cols] = new JButton();
            squares1[rows][cols].setSize(32, 32);
            squares1[rows][cols].setBorder(BorderFactory.createLineBorder(Color.BLACK));
            squares1[rows][cols].setBackground(Color.WHITE);
            childPanel1.add(squares1[rows][cols]);
        }
    }
}

public void childPanel2Setup()
{
    childPanel2 = new JPanel();
    childPanel2.setLayout(new GridLayout(row, column, 0, 0));
    childPanel2.setBorder(BorderFactory.createLineBorder(Color.BLACK));
    squares2 = new JButton[row][column];

    for(int rows = 0; rows < this.row; rows++)
    {
        for(int cols = 0; cols < this.column; cols++)
        {
            squares2[rows][cols] = new JButton();
            squares2[rows][cols].setSize(32, 32);
            squares2[rows][cols].setBorder(BorderFactory.createLineBorder(Color.BLACK));
            squares2[rows][cols].setBackground(Color.WHITE);
            childPanel2.add(squares2[rows][cols]);
        }
    }
}

public void childPanel3Setup()
{
    childPanel3 = new JPanel();
    childPanel3.setLayout(new GridLayout(row, column, 0, 0));
    childPanel3.setBorder(BorderFactory.createLineBorder(Color.BLACK));
    squares3 = new JButton[row][column];

    for(int rows = 0; rows < this.row; rows++)
    {
        for(int cols = 0; cols < this.column; cols++)
        {
            squares3[rows][cols] = new JButton();
            squares3[rows][cols].setSize(32, 32);
            squares3[rows][cols].setBorder(BorderFactory.createLineBorder(Color.BLACK));
            squares3[rows][cols].setBackground(Color.WHITE);
            childPanel3.add(squares3[rows][cols]);
        }
    }
}

public void childPanel4Setup()
{
    childPanel4 = new JPanel();
    childPanel4.setLayout(new GridLayout(row, column, 0, 0));
    childPanel4.setBorder(BorderFactory.createLineBorder(Color.BLACK));
    squares4 = new JButton[row][column];

    for(int rows = 0; rows < this.row; rows++)
    {
        for(int cols = 0; cols < this.column; cols++)
        {
            squares4[rows][cols] = new JButton();
            squares4[rows][cols].setSize(32, 32);
            squares4[rows][cols].setBorder(BorderFactory.createLineBorder(Color.BLACK));
            squares4[rows][cols].setBackground(Color.WHITE);
            childPanel4.add(squares4[rows][cols]);
        }
    }
}

public void childPanel5Setup()
{
    childPanel5 = new JPanel();
    childPanel5.setLayout(new GridLayout(row, column, 0, 0));
    childPanel5.setBorder(BorderFactory.createLineBorder(Color.BLACK));
    squares5 = new JButton[row][column];

    for(int rows = 0; rows < this.row; rows++)
    {
        for(int cols = 0; cols < this.column; cols++)
        {
            squares5[rows][cols] = new JButton();
            squares5[rows][cols].setSize(32, 32);
            squares5[rows][cols].setBorder(BorderFactory.createLineBorder(Color.BLACK));
            squares5[rows][cols].setBackground(Color.WHITE);
            childPanel5.add(squares5[rows][cols]);
        }
    }
}

public void childPanel6Setup()
{
    childPanel6 = new JPanel();
    childPanel6.setLayout(new GridLayout(row, column, 0, 0));
    childPanel6.setBorder(BorderFactory.createLineBorder(Color.BLACK));
    squares6 = new JButton[row][column];

    for(int rows = 0; rows < this.row; rows++)
    {
        for(int cols = 0; cols < this.column; cols++)
        {
            squares6[rows][cols] = new JButton();
            squares6[rows][cols].setSize(32, 32);
            squares6[rows][cols].setBorder(BorderFactory.createLineBorder(Color.BLACK));
            squares6[rows][cols].setBackground(Color.WHITE);
            childPanel6.add(squares6[rows][cols]);
        }
    }
}

public void childPanel7Setup()
{
    childPanel7 = new JPanel();
    childPanel7.setLayout(new GridLayout(row, column, 0, 0));
    childPanel7.setBorder(BorderFactory.createLineBorder(Color.BLACK));
    squares7 = new JButton[row][column];

    for(int rows = 0; rows < this.row; rows++)
    {
        for(int cols = 0; cols < this.column; cols++)
        {
            squares7[rows][cols] = new JButton();
            squares7[rows][cols].setSize(32, 32);
            squares7[rows][cols].setBorder(BorderFactory.createLineBorder(Color.BLACK));
            squares7[rows][cols].setBackground(Color.WHITE);
            childPanel7.add(squares7[rows][cols]);
        }
    }
}

public void childPanel8Setup()
{
    childPanel8 = new JPanel();
    childPanel8.setLayout(new GridLayout(row, column, 0, 0));
    childPanel8.setBorder(BorderFactory.createLineBorder(Color.BLACK));
    squares8 = new JButton[row][column];

    for(int rows = 0; rows < this.row; rows++)
    {
        for(int cols = 0; cols < this.column; cols++)
        {
            squares8[rows][cols] = new JButton();
            squares8[rows][cols].setSize(32, 32);
            squares8[rows][cols].setBorder(BorderFactory.createLineBorder(Color.BLACK));
            squares8[rows][cols].setBackground(Color.WHITE);
            childPanel8.add(squares8[rows][cols]);
        }
    }
}

public void childPanel9Setup()
{
    childPanel9 = new JPanel();
    childPanel9.setLayout(new GridLayout(row, column, 0, 0));
    childPanel9.setBorder(BorderFactory.createLineBorder(Color.BLACK));
    squares9 = new JButton[row][column];

    for(int rows = 0; rows < this.row; rows++)
    {
        for(int cols = 0; cols < this.column; cols++)
        {
            squares9[rows][cols] = new JButton();
            squares9[rows][cols].setSize(32, 32);
            squares9[rows][cols].setBorder(BorderFactory.createLineBorder(Color.BLACK));
            squares9[rows][cols].setBackground(Color.WHITE);
            childPanel9.add(squares9[rows][cols]);
        }
    }
}

}

}

回答by mcalex

I believe it's because the Layout Manager for JPanels is FlowLayoutwhich includes a margin. When you create the panels, set their layout to GridLayout which will give you 0 margin.

我相信这是因为JPanels的布局管理器FlowLayout包含一个边距。创建面板时，将它们的布局设置为 GridLayout，这将为您提供 0 边距。

Also have you done setVgap(0);and setHgap(0);for the GridLayout?

也有你做setVgap(0);，并setHgap(0);为GridLayout？

回答by Mikhail Vladimirov

GridLayout makes all component to be of the same size. If it needs to layout matrix of 3x3 components inside JPanel that it 100x100 pixels, each component will be 33x33 pixels and there will be on extra pixel at the right and at the bottom because 100 is not factor of 3. If JPanel is 101x101 pixels, there will be extra pixels at all four edges.

GridLayout 使所有组件的大小相同。如果它需要在 JPanel 内部布置 3x3 组件的矩阵，它是 100x100 像素，每个组件将是 33x33 像素，并且在右侧和底部会有额外的像素，因为 100 不是 3 的因数。如果 JPanel 是 101x101 像素，所有四个边缘都会有额外的像素。

Consider using GridBagLayout or Box or some other layout that is smarter than GridLayout.

考虑使用 GridBagLayout 或 Box 或其他一些比 GridLayout 更智能的布局。