如何修复GridBagLayout中的间隙

Question

我正在使用GridBagLayout创建一个名为'Preset'的JPanel，该JPanel在JFrame中被复制了几次。每个预设将有多行（JPanels）。我的目标是只显示一行（第一行），但是当单击编辑按钮时，它们都会全部显示。现在，编辑按钮可以使用，但是两行之间有很大的空间。我希望这样，当多余的行合拢时，每个“预设”将彼此直接位于上方（无空格）。您可以在下图中看到我在说什么。

外观如下：“ >>

这是我希望的外观：

我相当确定我需要对GridBag做一些事情，但是我不知道是什么。我已经阅读了几本教程，并按照我认为的样子写了它，但是没有运气。

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package SSCCE;

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;

public class UI extends JFrame{
    private final static int HEIGHT = 600;
    private final static int WIDTH = 730;
    private JPanel pane; //Pane that stores accounts
    private JScrollPane scroller;
    private Preset[] branches;    

    public static void main(String[] args) {
        JFrame frame = new UI();
    }    

    public UI(){
        //Make the UI close when the exit button is clicked
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);    

        //Sets the size of the UI
        this.setSize(WIDTH, HEIGHT);

        //Set the layout and add components to it
        this.setLayout(new BorderLayout());

        //Reads in the settings and sets up the branches
        populateBranches();

        pane = new JPanel();
        pane.setLayout(new GridLayout(branches.length,1));
        for (int i = 0; i < branches.length; i++){
            pane.add(branches[i]);
        }

        //Create the center pane of the BorderLayout
        scroller = new JScrollPane(pane);
        scroller.createVerticalScrollBar();
        this.add(scroller,BorderLayout.CENTER);

        //Makes the UI visible
        this.setVisible(true);
    }

    private void populateBranches(){
        //Populates the branches array based on what is read in, or not read in from the file
        branches = new Preset[15];

    for (int i = 0; i < branches.length; i++){
        branches[i] = new Preset();
        branches[i].setEnabled(false);
    }
}

public class Preset extends JPanel{
    private JTextField eName;
    private JButton edit;
    private JButton activate;
    private JComboBox printer;
    private JPanel line1;
    private JPanel line2;
    private String branchName;
    private String ipAddress;
    private boolean enableAll;

    public Preset(){
        eName = new JTextField(20);
        edit = new JButton("Edit");
        activate = new JButton("Activate");

        JPanel nameContainer = new JPanel();
        nameContainer.setLayout(new FlowLayout());
        nameContainer.add(eName);

        printer = new JComboBox();

        //
        line1 = new JPanel();
        line1.setLayout(new FlowLayout());
        line1.add(nameContainer);
        line1.add(edit);
        line1.add(activate);

        //
        line2 = new JPanel();
        line2.setLayout(new BorderLayout());
        line2.add(printer, BorderLayout.WEST);

        GridBagLayout grid = new GridBagLayout();
        GridBagConstraints cons = new GridBagConstraints();
        cons.fill = GridBagConstraints.BOTH;
        this.setLayout(grid);

        cons.ipady = 100;
        cons.ipadx = 100;
        cons.weighty = 0D;
        cons.gridx = 0;
        cons.gridy = 0;
        cons.gridwidth = 2;
        cons.gridheight = 1;
        grid.setConstraints(line1, cons);
        this.add(line1);

        cons.ipady = 100;
        cons.ipadx = 100;
        cons.weighty = 0D;
        cons.gridx = 0;
        cons.gridy = 1;
        cons.gridwidth = 2;
        cons.gridheight = 1;
        grid.setConstraints(line2, cons);
        this.add(line2);

        //Enable all components
        enableAll = true;
    }
}
}

我正在使用GridBagLayout创建一个名为'Preset'的JPanel，该JPanel在JFrame中被复制了几次。每个预设将有多行（JPanels）。我的目标是只有一行（第一行）...

Answer 1

[删除GridBagConstraints Preset的JPanel的Y轴中分配填充的所有语句，即>]

cons.ipady = 100;

Answer 2

我不认为这是对您问题的“真正”答案，但是您需要考虑的一些事项：摆脱困境。我看不到您想要的布局中需要它的任何东西。用两个子面板创建每个面板；第二个子面板包含您希望默认情况下不可见并稍后显示的内容，然后使用setVisible（）进行操作。

Answer 3

这是对背景问题（如何获得所需效果）的真实答案：

Answer 4

我遇到了同样的问题，找到了70％的解决方案。如果您使用rowWeights并将除最后一个组件（rowWeights 1.0）以外的所有组件都设置为0，则几乎所有空格都消失了。如果您包含的组件大于所有其他组件，则仅在最后一个组件之前留有空隙。