如何使用 MigLayout 将内容集中在多个面板上？

Question

我有一个大面板，其中包含 3 个较小的面板（locationPanel、usagePanel、structuralAspectsPanel）。

每个较小的面板上都有一些JLabels 和JCheckBoxes。我继续将每个面板上的组件居中，但是我怎样才能在所有 3 个面板上完成居中呢？ （请看中间的黑线）

我尝试在MigLayout (new JLabel("Label here"), "cell 0 0") 中使用单元格布局选项，但无法动态创建相同大小的间隙，以便所有组件居中。使用gap 200 (180, 300 , ...) 将组件“推”到视觉中心似乎可行，但我想避免使用绝对定位/间隙，因为它们可能很容易损坏。

我附上了我的问题的图片：

这是我的源代码：

public class RiskAssessmentPage extends JPanel {
  JPanel riskAssessmentPanel = new JPanel();

  JPanel locationPanel = new JPanel();
  JPanel usagePanel = new JPanel();
  JPanel structuralAspectsPanel = new JPanel();

  public RiskAssessmentPage() {
    setLayout(new MigLayout(""));
    riskAssessmentPanel.setLayout(
        new MigLayout("wrap", "[grow, fill]", "[grow, fill, push][grow, fill, push][grow, fill, push]"));

    locationPanel.setLayout(new MigLayout("gap rel 2", "[grow, center][grow, left]"));
    locationPanel.setBorder(BorderFactory.createTitledBorder("Location"));

    usagePanel.setLayout(new MigLayout("gap rel 2", "[grow, center][grow, left]"));
    usagePanel.setBorder(BorderFactory.createTitledBorder("Usage"));

    structuralAspectsPanel.setLayout(new MigLayout("gap rel 2", "[grow, center][grow, left]"));
    structuralAspectsPanel.setBorder(BorderFactory.createTitledBorder("Structural Aspects"));

    locationPanel.add(new JLabel("This is the first of all labels"));
    locationPanel.add(new JCheckBox("Checkbox with Label"), "wrap");
    locationPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    locationPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    locationPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    locationPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    locationPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    locationPanel.add(new JSeparator(), "growx, span");
    locationPanel.add(new JLabel("Second Label"));
    locationPanel.add(new JCheckBox("Checkbox with Label"), "wrap");
    locationPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    locationPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    locationPanel.add(new JSeparator(), "growx, span");
    locationPanel.add(new JLabel("This Label is fairly large and long and pushes the text around"));
    locationPanel.add(new JCheckBox("Checkbox with Label"), "wrap");
    locationPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    locationPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");

    usagePanel.add(new JLabel("A label in the usage panel"));
    usagePanel.add(new JCheckBox("Checkbox with Label"), "wrap");
    usagePanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    usagePanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    usagePanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    usagePanel.add(new JSeparator(), "growx, span");
    usagePanel.add(new JLabel("And another one and another one and another one"));
    usagePanel.add(new JCheckBox("Checkbox with Label"), "wrap");
    usagePanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    usagePanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    usagePanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    usagePanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    usagePanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    usagePanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");

    structuralAspectsPanel.add(new JLabel("Label here"));
    structuralAspectsPanel.add(new JCheckBox("Checkbox with Label"), "wrap");
    structuralAspectsPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    structuralAspectsPanel.add(new JSeparator(), "growx, span");
    structuralAspectsPanel.add(new JLabel("I am so uncreative with label names..."));
    structuralAspectsPanel.add(new JCheckBox("Checkbox with Label"), "wrap");
    structuralAspectsPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    structuralAspectsPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    structuralAspectsPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    structuralAspectsPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    structuralAspectsPanel.add(new JSeparator(), "growx, span");
    structuralAspectsPanel.add(new JLabel("Thats it. I give up with naming them."));
    structuralAspectsPanel.add(new JCheckBox("Checkbox with Label"), "wrap");
    structuralAspectsPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
    structuralAspectsPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");

    riskAssessmentPanel.add(locationPanel);
    riskAssessmentPanel.add(usagePanel);
    riskAssessmentPanel.add(structuralAspectsPanel);

    add(riskAssessmentPanel, "grow, push");
  }
}

Answer 1

我想通了，其实很简单！

将0:0, grow 60 添加到第一列，将grow 40 添加到第二列。

grow 60 / 40-part 表示左列占可用宽度的 60%，而另一列占 40%。

0:0-部分是关于设置最小/首选/最大宽度（尽管我不得不承认我不完全理解它，欢迎解释！...我已经 opened a question 只是为了这个。）。

由于所有面板的左右尺寸相同，因此它们的中心位于同一点。

locationPanel.setLayout(new MigLayout("gap rel 2", "[0:0, grow 60, center][grow 40, left]"));

usagePanel.setLayout(new MigLayout("gap rel 2", "[0:0, grow 60, center][grow 40, left]"));

structuralAspectsPanel.setLayout(new MigLayout("gap rel 2", "[0:0, grow 60, center][grow 40, left]"));

Answer 2

为了使您的面板列对齐，您需要将它们设置为相同的大小。在MigLayout 中，您可以通过将第一列的首选大小 和增长率 设置为所有面板中的相同值来做到这一点。例如

panel1.new MigLayout("", //Unchanged Layout Constraints
        "[:500, grow, center][grow, left]", //Column Constraints
        ""); //Unchanged Row Constraints

panel2.new MigLayout("", //Unchanged Layout Constraints
        "[:500, grow, center][grow, left]", //Column Constraints
        ""); //Unchanged Row Constraints

在此示例中，panel1 和 panel2 的第一列的首选大小设置为 500，增长设置为其默认值，因此也是相同的。

可以在此处查看所描述内容的工作示例

import java.awt.*;
import javax.swing.*;
import net.miginfocom.swing.MigLayout;

public class MigLay extends JFrame {

    private MigLay() {
        super("Button Layout");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new MigLayout("wrap", //Layout Constraints
        "grow, fill", //Column Constraints
        "grow, fill")); //Row Constraints
        createPanels();
        pack();
        setMinimumSize(getSize()); //Sets minimum size to the preferred size. Remove or change this line if you do not want that to happen
        setVisible(true);
    }

    private void createPanels() {

        JPanel locationPanel = new JPanel();
        JPanel usagePanel = new JPanel();
        JPanel structuralAspectsPanel = new JPanel();

        //JLabels for font metrics
        JLabel one = new JLabel("This is the first of all labels");
        JLabel two = new JLabel("Second Label");
        JLabel three = new JLabel("This Label is fairly large and long and pushes the text around");
        JLabel four = new JLabel("A label in the usage panel");
        JLabel five = new JLabel("And another one and another one and another one");

        //Font Metrics
        FontMetrics metrics = three.getFontMetrics(three.getFont()); //Take longest label manually or dynamically (You will have to add that code)
        int width = metrics.stringWidth(three.getText());

        locationPanel.setLayout(new MigLayout("gap rel 2", "[:" + width + ", grow, center][grow, left]"));
        locationPanel.setBorder(BorderFactory.createTitledBorder("Location"));

        usagePanel.setLayout(new MigLayout("gap rel 2", "[:" + width + ", grow, center][grow, left]"));
        usagePanel.setBorder(BorderFactory.createTitledBorder("Usage"));

        locationPanel.add(one);
        locationPanel.add(new JCheckBox("Checkbox with Label"), "wrap");
        locationPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
        locationPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
        locationPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
        locationPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
        locationPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
        locationPanel.add(new JSeparator(), "growx, span");
        locationPanel.add(two);
        locationPanel.add(new JCheckBox("Checkbox with Label"), "wrap");
        locationPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
        locationPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
        locationPanel.add(new JSeparator(), "growx, span");
        locationPanel.add(three);
        locationPanel.add(new JCheckBox("Checkbox with Label"), "wrap");
        locationPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
        locationPanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");

        usagePanel.add(four);
        usagePanel.add(new JCheckBox("Checkbox with Label"), "wrap");
        usagePanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
        usagePanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
        usagePanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
        usagePanel.add(new JSeparator(), "growx, span");
        usagePanel.add(five);
        usagePanel.add(new JCheckBox("Checkbox with Label"), "wrap");
        usagePanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
        usagePanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
        usagePanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
        usagePanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
        usagePanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");
        usagePanel.add(new JCheckBox("Checkbox with Label"), "skip, wrap");

        getContentPane().add(locationPanel);
        getContentPane().add(usagePanel);
    }

    public static void main(String[] args) {
        new MigLay();
    }
}