如何从右边开始向JPanel添加按钮？

Question

如何从右到左添加按钮和其他组件到JPanel？我曾使用BorderLayout经理来做到这一点，但它不起作用，它们被插入到屏幕中间！

我该怎么做？

Answer 1

以正确的对齐方式添加其他JPanel和FlowLayout。

JPanel panel = new JPanel(new FlowLayout(FlowLayout.RIGHT), 0, 5); // 0 for horizontal gap

Answer 2

重要的是要澄清这个问题，因为与右边对齐的内容和从右到左添加的内容之间存在差异......

与右边对齐......

您可以通过多种方式将组件对齐到右侧，您可以使用GridBagLayout，但最简单的方法可能是使用FlowLayout

import java.awt.ComponentOrientation;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class Test {

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

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() {
            setLayout(new FlowLayout(FlowLayout.RIGHT));
            add(new JLabel("Aligned"));
            add(new JLabel("to"));
            add(new JLabel("the"));
            add(new JLabel("right"));
        }

    }

}

添加到右到左......

这只是使用Component#setComponentOrientation并将其设置为ComponentOrientation.RIGHT_TO_LEFT以更改组件的布局方向

import java.awt.ComponentOrientation;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class Test {

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

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() {
            setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
            setLayout(new FlowLayout(FlowLayout.RIGHT));
            add(new JLabel("Starting"));
            add(new JLabel("from"));
            add(new JLabel("the"));
            add(new JLabel("right"));
        }

    }

}