java swing 调整大小

Question

我正在编写一个库，其中传递了一个容器（通常是 JPanel）

，并且有一个针对不同控件、它们的位置、大小和其他属性的 xml 规范。我必须在运行时创建这些控件并将其添加到组件中。处理父容器大小调整的好方法是什么？

Answer 1

如果 XML 指定了绝对位置，那么可能无法优雅地调整组件的大小。您可以创建一个自定义布局管理器来线性缩放它们，但这对于大多数组件来说可能看起来很糟糕。

编辑：这是一个可能有用的版本：

public class LinearScaleLayout {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Linear Scale Layout Test");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setBounds(100, 100, 200, 200);

        JPanel scalePanel = new JPanel(new LinearScaleLayoutManager());
        scalePanel.setBorder(new EmptyBorder(5, 5, 5, 5));
        scalePanel.add(new JTextField(), new Rectangle2D.Double(0, 0, 1, 0.2));
        scalePanel.add(new JScrollPane(new JEditorPane()), new Rectangle2D.Double(0, 0.25, 0.45, 0.75));
        scalePanel.add(new JSlider(), new Rectangle2D.Double(0.55, 0.25, 0.45, 0.75));

        frame.getContentPane().add(scalePanel);
        frame.setVisible(true);
    }

    private static class LinearScaleLayoutManager implements LayoutManager2 {
        private final HashMap<Component, Rectangle2D> rectMap = new HashMap<Component, Rectangle2D>();

        @Override
        public void layoutContainer(Container parent) {
            synchronized (parent.getTreeLock()) {
                Insets insets = parent.getInsets();
                int clientWidth = parent.getWidth() - insets.left - insets.right;
                int clientHeight = parent.getHeight() - insets.top - insets.bottom;
                if (clientWidth > 0 && clientHeight > 0) {
                    for (Component component : parent.getComponents()) {
                        Rectangle2D rect = rectMap.get(component);
                        if (rect != null) {
                            component.setBounds(new Rectangle(insets.left + (int)(rect.getX() * clientWidth), 
                                    insets.top + (int)(rect.getY() * clientHeight), (int)(rect.getWidth() * clientWidth), 
                                    (int)(rect.getHeight() * clientHeight)));
                        }
                    }
                }
            }
        }

        @Override
        public void addLayoutComponent(Component comp, Object constraints) {
            rectMap.put(comp, (Rectangle2D)constraints);
        }

        @Override
        public void removeLayoutComponent(Component comp) {
            rectMap.remove(comp);
        }

        @Override
        public Dimension minimumLayoutSize(Container parent) {
            return new Dimension(0, 0);
        }

        @Override
        public Dimension preferredLayoutSize(Container parent) {
            return new Dimension(100, 100);
        }

        @Override
        public Dimension maximumLayoutSize(Container target) {
            return new Dimension(Integer.MAX_VALUE, Integer.MAX_VALUE);
        }

        @Override
        public void addLayoutComponent(String name, Component comp) {
        }

        @Override
        public float getLayoutAlignmentX(Container target) {
            return 0;
        }

        @Override
        public float getLayoutAlignmentY(Container target) {
            return 0;
        }

        @Override
        public void invalidateLayout(Container target) {
        }
    }
}