面板顶部的图形 [英] Graphics on top of a Panel

问题描述

我在面板上有一个JLabel的图形上绘制图形时遇到了麻烦.我正在使用自定义的paintComponent(Graphics g)方法在面板上绘制一个字符串.我希望字符串显示在JLabel的顶部而不是JLabel的下面，这是当前正在发生的情况.如果您想看到它，这是paintComponent方法:

I am having trouble with the Graphics that I am drawing on a Panel which has a JLabel on top of it. I am using a custom paintComponent(Graphics g) method to draw a String on the Panel. I want the string to show on top of the JLabel instead of under the JLabel, which is what is currently happening. Here is the paintComponent method if you want to see it:

public void paintComponent(Graphics g){
    super.paintComponent(g);

    if(a.shouldAnnotate()){
        FontMetrics size= g.getFontMetrics(); 
        if(getWidth()>=(a.dispX()+size.stringWidth(a.annotationText()))){
            g.setColor(Color.white);
            g.fillRect(a.dispX()-3,a.dispY()-12,size.stringWidth(a.annotationText())+5,15);
            g.setColor(Color.black);
            g.drawRect(a.dispX()-3,a.dispY()-12,size.stringWidth(a.annotationText())+5,15);
            g.drawString(a.annotationText(), a.dispX(), a.dispY());
        }else{
            String sub="";
            int letters=0;
            g.setColor(Color.white);
            g.fillRect(a.dispX()-3,a.dispY()-12,getWidth(),15);
            g.setColor(Color.black);

            for(int i=0;i<a.annotationText().length();i++){
                if(a.dispX()+letters+16<=getWidth()){
                    sub+=a.annotationText().substring(i,i+1);
                    letters=size.stringWidth(sub);
                }else{
                    sub=sub+"...";
                    i=a.annotationText().length();
                }
            }
            g.drawRect(a.dispX()-3,a.dispY()-12,size.stringWidth(sub)+3,15);
            g.drawString(sub,a.dispX(),a.dispY());
        }
    }
}

我不太喜欢图形，但是我需要学习解决此问题的方法.

I don't like graphics much but I need to learn the fix of this problem.

推荐答案

为此，我认为您必须覆盖paint或paintChildren，并在此处绘制文本:

To do this I think that you must either override paint or paintChildren, and draw your text there:

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;

import javax.swing.*;

@SuppressWarnings("serial")
public class DrawOverLabel extends JPanel {
   private static final int PREF_W = 500;
   private static final int PREF_H = 100;
   private static final Font TEXT_FONT = new Font(Font.SANS_SERIF, Font.BOLD, 32);
   private static final int LABEL_COUNT = 40;

   public DrawOverLabel() {
      for (int i = 0; i < LABEL_COUNT; i++) {
         JLabel label = new JLabel("Label");
         label.setForeground(Color.green);
         label.setFont(label.getFont().deriveFont(Font.BOLD, 20));
         add(label);
      }
   }

   @Override
   public void paint(Graphics g) {
      super.paint(g);

      g.setColor(Color.blue);
      g.setFont(TEXT_FONT);
      g.drawString("in paint", 20, 30);

//      super.paint(g);
   }

   @Override
   protected void paintComponent(Graphics g) {
      super.paintComponent(g);

      g.setColor(Color.red);
      g.setFont(TEXT_FONT);
      g.drawString("in paintComponent", 20, 60);

//      super.paintComponent(g);
   }

   @Override
   protected void paintChildren(Graphics g) {
      super.paintChildren(g);

      g.setColor(Color.gray);
      g.setFont(TEXT_FONT);
      g.drawString("in paintChildren", 20, 100);

//       super.paintChildren(g);
   }

   @Override
   public Dimension getPreferredSize() {
      return new Dimension(PREF_W, PREF_H);
   }

   private static void createAndShowGui() {
      JFrame frame = new JFrame("DrawOverLabel");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.getContentPane().add(new DrawOverLabel());
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}

但是更好的解决方案是使用JLayeredPane或玻璃窗格来实现此效果.

But a better solution is to use a JLayeredPane or the glasspane for this effect.

这篇关于面板顶部的图形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IT屋！