paintComponent（）正在绘制其他组件

本文介绍了paintComponent（）正在绘制其他组件的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 29岁程序员，3月因学历无情被辞！ 我正在使用自定义类，根据此答案中的代码，绘制一个形状像会话框。每当我调整应用程序窗口的大小足以使组件在顶部或底部突出时，所述组件的轮廓将在 JScrollPane 之外的其他组件之外绘制;在这种情况下 JPanel 。I'm using a custom class, based on the code in this answer, to draw a background shaped like a speech bubble. Whenever I resize the window of my application enough to make a component poke out at the top or bottom, the outlines of the said component is drawn outside the JScrollPane on top of other components; in this case the JPanel.在左侧图像中，组件底部的边框由于组件仍然可见，因此绘制了 JScrollPane ;而在右侧图像中，所提到的组件不再可见，一切看起来都是预期的。In the left-side image, the border of the component at the bottom of the JScrollPane is drawn, due to the component still being visible; while in the right-side image, the mentioned component is no longer visible and everything looks as intended.我认为这与我是这样的事实有关使用 JScrollPane 来包含组件，从而允许组件在 JPanel 下滑动。我如何防止这种情况？I believe it has something to do with the fact that I'm using a JScrollPane to contain the components and thus allowing the component to slide under the JPanel. How do I prevent this?主要：public class Main { public static void main(String[] args) { JPanel panel = new JPanel(), panelbar = new JPanel(); panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS)); panelbar.setLayout(new FlowLayout()); JScrollPane scroll = new JScrollPane(panel, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER); JFrame frame = new JFrame(""); frame.setLayout(new BorderLayout()); frame.setSize(200, 223); for (int i = 0; i < 6; i++) { JLabel label = new JLabel("JLabel"); label.setBorder(new CustomBorder()); label.setOpaque(true); label.setBackground(Color.ORANGE); panel.add(label); } panelbar.add(new JLabel("JPanel")); frame.add(scroll, BorderLayout.CENTER); frame.add(panelbar, BorderLayout.SOUTH); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); }}自定义类：public class CustomBorder extends AbstractBorder { private static final long serialVersionUID = 1L; Insets i; CustomBorder() { i = new Insets(10, 20, 10, 20); } @Override public void paintBorder(Component c, Graphics g, int x, int y, int width, int height) { super.paintBorder(c, g, x, y, width, height); Polygon bubble = new Polygon(); bubble.addPoint(x + 10, y + 5); bubble.addPoint(x + width - 10, y + 5); bubble.addPoint(x + width - 10, y + height / 3); bubble.addPoint(x + width, y + height / 2); bubble.addPoint(x + width - 10, y + height * 2 / 3); bubble.addPoint(x + width - 10, y - 5 + height); bubble.addPoint(x + 10, y - 5 + height); Graphics2D g2d = (Graphics2D) g; Area rect = new Area(new Rectangle(x, y, width, height)); rect.subtract(new Area(bubble)); g2d.setClip(rect); g2d.setColor(c.getParent().getBackground()); g2d.fillRect(0, 0, width, height); g2d.setClip(null); g2d.setColor(Color.BLACK); g2d.draw(bubble); } @Override public Insets getBorderInsets(Component c) { return i; } @Override public Insets getBorderInsets(Component c, Insets insets) { return i; }}推荐答案那里剪辑代码有两个问题：There are two problems with the clipping code: 在减去气泡时，你不会从原始剪辑开始（导致组件成为在滚动窗格外绘制） 在绘制气泡之前，您不会恢复原始剪辑：更改将是：@Overridepublic void paintBorder(Component c, Graphics g, int x, int y, int width, int height) { super.paintBorder(c, g, x, y, width, height); Polygon bubble = new Polygon(); bubble.addPoint(x + 10, y + 5); bubble.addPoint(x + width - 10, y + 5); bubble.addPoint(x + width - 10, y + height / 3); bubble.addPoint(x + width, y + height / 2); bubble.addPoint(x + width - 10, y + height * 2 / 3); bubble.addPoint(x + width - 10, y - 5 + height); bubble.addPoint(x + 10, y - 5 + height); Graphics2D g2d = (Graphics2D) g; //Area rect = new Area(new Rectangle(x, y, width, height)); Shape clip = g2d.getClip(); Area rect = new Area(clip); rect.subtract(new Area(bubble)); g2d.setClip(rect); g2d.setColor(c.getParent().getBackground()); g2d.fillRect(0, 0, width, height); //g2d.setClip(null); g2d.setClip(clip); g2d.setColor(Color.BLACK); g2d.draw(bubble);} 这篇关于paintComponent（）正在绘制其他组件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！ 上岸，阿里云！