java - 将顶部与 JPanel 中新行中的每个元素垂直对齐

Question

我有一个 JPanel，面板中包含一组其他 JPanel(每个 JPanel 都包含一个 JLabel)。如何设置面板，使内部 JPanel 与 JPanel 的顶部垂直对齐，并且每个内部面板进入新行。喜欢:

InnerPanel 1
InnerPanel 2
InnerPanel 3


// empty space

我尝试不设置布局(使用默认布局)，但内部面板位于同一行，直到该行被填满。喜欢:

InnerPanel 1 InnerPanel 2 InnerPanel 3
InnerPanel 4



// empty space

我还尝试过 BoxLayout 和 GridBagLayout，但内部面板空间占用了面板的整个垂直空间，如下所示:

InnerPanel 1


InnerPanel 2


InnerPanel 3

代码:

public class HomeStream extends JPanel
    public HomeStream()
    {
        this.setLayout(new GridBagLayout());
        int counter = 0;

        // HomeStreamContent is the inner panel here containing a JLabel
        for (HomeStreamContent hsc : this.content)
        {
            this.add(hsc, getConstraints(0, counter++));
        }
    }

    public static GridBagConstraints getConstraints(int x, int y)
    {
        GridBagConstraints c = new GridBagConstraints();
        c.gridx = x;
        c.gridy = y;
        c.weightx = 1.0;
        c.weighty = 0.1;
        c.insets = new Insets(10, 10, 10, 10);
        c.anchor = GridBagConstraints.PAGE_START;
        c.fill = GridBagConstraints.HORIZONTAL;

        return c;
    }

Answer 1

使用BoxLayout，您需要将面板的maximumSize设置为preferredSize，因为如果您所以对于每个内部面板，您都可以这样做

JPanel panel = new JPanel() {
    @Override       
    public Dimension getMaximumSize() {
        return getPreferredSize();
    }
};

<小时/>

import javax.swing.Box;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class TestBoxLayout {

    public TestBoxLayout() {
        Box box = Box.createVerticalBox();
        for (int i = 1; i < 4; i++) {
            JPanel panel = new JPanel() {
                @Override
                public Dimension getMaximumSize() {
                    return getPreferredSize();
                }
            };
            JLabel label1 = new JLabel("Label");
            JLabel label2 = new JLabel(String.valueOf(i));
            panel.add(label1);
            panel.add(label2);
            box.add(panel);

        }

        JFrame frame = new JFrame();
        frame.add(box);
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }

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

<小时/>

不设置最大值

导入javax.swing.Box;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class TestBoxLayout {

    public TestBoxLayout() {
        Box box = Box.createVerticalBox();
        for (int i = 1; i < 4; i++) {
            JPanel panel = new JPanel();
            JLabel label1 = new JLabel("Label");
            JLabel label2 = new JLabel(String.valueOf(i));
            panel.add(label1);
            panel.add(label2);
            box.add(panel); 
        }

        JFrame frame = new JFrame();
        frame.add(box);
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }

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