java - 垂直 View 中的可拖动组件 (Java Swing)

Question

这是我在这个平台上的第一个问题，所以请耐心等待:

我正在使用 Java Swing 制作一个 LayerPanel，就像在 Photoshop 中一样，其中 LayerPanel 的每个子级也是代表一个图层的面板。就像在 Photoshop 中一样，我使用鼠标通过 DraggableComponent 类移动 LayerPanel 的这些子级，其灵感来自于:在此处输入图像描述regable-component>。

问题在于重新排列 UI 中的图层。我无法在 UI 中交换面板。

这是我迄今为止的代码:

可拖动组件:

class DraggableComponent extends JPanel implements MouseListener, MouseMotionListener {

    private LayerPanel panel;

    private volatile int screenY = 0;
    private volatile int myY = 0;

    private String name;

    public DraggableComponent(LayerPanel panel, String name) {
        setPreferredSize(new Dimension(300, 80));
        this.name = name;
        this.panel = panel;
        updateBorder(name);
        setVisible(true);

        setLayout(null);

        addMouseListener(this);
        addMouseMotionListener(this);
    }

    private void updateBorder(String name) {
        setBorder(new TitledBorder(new DropShadowBorder(), name, TitledBorder.LEADING, TitledBorder.BELOW_TOP, null, null));
    }

    private void handleLocation(int y) {
        if (y >= getParent().getHeight() - this.getHeight()) {
            setLocation(getLocation().x, getParent().getHeight() - this.getHeight());
        } else setLocation(getLocation().x, Math.max(y, 0));
    }

    @Override
    public void mousePressed(MouseEvent e) {
        screenY = e.getYOnScreen();
        myY = getY();
    }

    @Override
    public void mouseReleased(MouseEvent e) {
        panel.handleReleased(this);
    }

    @Override
    public void mouseDragged(MouseEvent e) {
        int deltaY = e.getYOnScreen() - screenY;

        handleLocation(myY + deltaY);
        panel.handleLocation(this);
    }

    public void rename(String name) {
        this.name = name;
        updateBorder(name);
    }
}

LayerPanel 类:

public class LayerPanel extends JPanel {

    private ArrayList<DraggableComponent> components = new ArrayList<>();
    protected int HEIGHT_PER_COMPONENT;

    public LayerPanel(int height, int amountOfComponents) {
        setPreferredSize(new Dimension(200, height));
        setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));

        for (int i = 0; i < 10; i++) {
            components.add(new DraggableComponent(this, Integer.toString(i)));
        }

        updateComponents();
    }

    public void addComponent(String name) {
        components.add(new DraggableComponent(this, name));
        updateComponents();
    }

    private void updateComponents() {
        HEIGHT_PER_COMPONENT = getHeight() / (components.size() + 1);
        removeAll();

        for (DraggableComponent c : components) {
            //c.rename(Integer.toString(components.indexOf(c)));
            add(c);
            c.setLocation(0, HEIGHT_PER_COMPONENT * components.indexOf(c));
        }
    }

    public void handleReleased(DraggableComponent component) {
        updateComponents();
    }

    public void handleLocation(DraggableComponent component) {
        final int index = components.indexOf(component);

        for (DraggableComponent nextComponent : components) {
            final int indexNext = components.indexOf(nextComponent);
            if (component.getY() >= nextComponent.getY() - HEIGHT_PER_COMPONENT / 2 && !component.equals(nextComponent)) {
                Collections.swap(components, indexNext, indexNext - 1);
                updateComponents();
            }
        }
    }

    public static void main(String[] args) {
        JFrame f = new JFrame("Layers test");

        LayerPanel panel = new LayerPanel(800, 10);

        f.add(panel);
        f.setSize(300, 800);
        f.setLocationRelativeTo(null);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setVisible(true);
    }
}

Answer 1

The problem lies in re-arranging the layers.

无需自己管理。

这由面板中组件的 ZOrder 控制。

在您的 mousePressed 事件中，您可以将组件的 ZOrder 设置为 0，以确保该组件最后绘制，这意味着它现在将绘制面板上的所有其他组件。

类似于:

Container container = e.getComponent().getParent();
container.setComponentZOrder(e.getComponent(), 0);