强制最小JPanel大小

Question

我正在尝试使用Java Swing为小型电话本应用程序编写布局.我遇到了一个我无法修复的大小问题.我希望过滤器(在搜索结果下显示)足够宽,以便在搜索短语很短时显示整个标题.这是它的样子:

如你所见,名字缩短了.姓氏带有更长的文本,并按我的要求显示.

过滤类:

import javax.swing.*;
import javax.swing.border.CompoundBorder;
import java.awt.*;

public class Filter
{
    private JLabel label;
    private JPanel filterPane;

    Filter(String name)
    {
        // Filter text
        label = new JLabel();
        label.setForeground(new Color(0xAA0000));

        // Closing button
        JButton closeButton = new JButton("X");
        closeButton.setFont(new Font("Dialog", Font.BOLD, 20));
        closeButton.setMargin(new Insets(0, 0, 0, 0));

        filterPane = new JPanel();
        filterPane.setLayout(new BoxLayout(filterPane, BoxLayout.X_AXIS));
        // Frame with title + 50px padding on the right side for the next filter
        filterPane.setBorder(new CompoundBorder(
                BorderFactory.createEmptyBorder(0, 0, 0, 50),
                BorderFactory.createTitledBorder(name)));
        filterPane.add(closeButton);
        filterPane.add(Box.createRigidArea(new Dimension(5, 0)));
        filterPane.add(label);
        filterPane.setVisible(false);
    }

    public void setValue(String value) {
        if (value == null || value.isEmpty())
            filterPane.setVisible(false);
        else
        {
            this.label.setText(value);
            filterPane.setVisible(true);
        }
    }

    public JPanel getFilterPane() {
        return filterPane;
    }
}

主要课程:

import javax.swing.*;
import java.awt.*;
import java.lang.reflect.InvocationTargetException;

public class TestWindow
{
    private static void init()
    {
        JFrame frame = new JFrame("Stackoverflow test window");
        frame.setSize(new Dimension(480, 320));
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationRelativeTo(null);

        // Main panel - 20 px padding from each side
        JPanel pane = new JPanel();
        pane.setLayout(new BorderLayout());
        pane.setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));

        // Create panel for filters
        JPanel filterPane = new JPanel();
        filterPane.setLayout(new BoxLayout(filterPane, BoxLayout.X_AXIS));
        filterPane.setPreferredSize(new Dimension(0, 60));

        // Add sample filters
        Filter filter = new Filter("name");
        filter.setValue("i");
        filter.getFilterPane().setAlignmentY(Component.BOTTOM_ALIGNMENT);
        filterPane.add(filter.getFilterPane());

        filter = new Filter("surname");
        filter.setValue("loooooong text");
        filter.getFilterPane().setAlignmentY(Component.BOTTOM_ALIGNMENT);
        filterPane.add(filter.getFilterPane());

        // Add everything to main panel
        pane.add(new JTextArea("Nothing fancy here, just to fill out space"), BorderLayout.CENTER);
        pane.add(filterPane, BorderLayout.SOUTH);
        frame.setContentPane(pane);
        frame.setVisible(true);
    }

    public static void main (String [] args) throws InterruptedException, InvocationTargetException {
        SwingUtilities.invokeLater(TestWindow::init);
    }
}

我想setMinimumSize和setPreferredSize两个label并filterPane在过滤器的构造,但它并没有帮助.请问你能帮帮我吗？

Answer 1

这个问题实际上是由两个问题组成的.

1. 使用时TitledBorder,组件在计算其首选大小时不会考虑标题的大小.
2. 使用时BoxLayout,除非在组件后面添加"水平胶水",否则将忽略首选宽度.

因此,要解决第一个问题,您需要覆盖getPreferredSize()JPanel 的方法.但要实现这一点,您还需要通过添加胶水来绕过第二个问题.

要覆盖getPreferredSize(),您可以使用以下内容:

class MinSizePanel extends JPanel {

    public Dimension getPreferredSize() {
        Dimension original = super.getPreferredSize();
        TitledBorder titleBorder = (TitledBorder)((CompoundBorder)getBorder()).getInsideBorder();
        int width = (int)Math.max( original.getWidth(), 60 + (int)titleBorder.getMinimumSize(this).getWidth());
        return new Dimension( width, (int)original.getHeight() );
    }
}

这得到了TitledBorder来自CompoundBorder,得到它的最小尺寸(这是一个考虑标题宽度的方法),为空边框和插图添加一些额外的(你可以添加适当的计算,我做了一个快捷方式,只是使用60.. .),并使用它(如果它超过组件的宽度).

代替

filterPane = new JPanel();

使用

filterPane = new MinSizePanel();

(您应该将面板构造的所有其余部分移动到该类中).

在TestWindow课堂上,在最后一课之后

    filterPane.add(filter.getFilterPane());

还添加

    filterPane.add(Box.createHorizontalGlue());