java - 在 1 个 JFrame 中混合两个 JPanel 的问题

Question

我在一帧中混合了两个 JPanels，它给了我这个输出!

这是我添加两个 JPanel 的代码:

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.*;
import java.util.*;

public class Board extends JFrame{
private int width=500;
private int height=450;

Obstacles asd= new Obstacles();

Human human;    
private Dimension mindim= new Dimension(width+10,height+10);

Board(){
    human = new Human();
    this.setTitle("Athwart");
    //setLayout(null);
    human.add(asd);     //!!!we see here, I add asd (which is inherited from a JPanel)     
                        //  to another existing JPanel
    this.setMinimumSize(mindim); //
    this.getContentPane().setLayout(new BorderLayout());
    this.getContentPane().add(human); 
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //
    this.setLocationRelativeTo(null); //
    this.setResizable(true); //
    pack(); //
    setVisible(true);
    human.requestFocus(); //
    }
}

这就是我的 Obstacles 类的样子。

import javax.swing.*;
import java.awt.*;

public class Obstacles extends JPanel {

private int width=500;
private int height=450;  
private Dimension mindim= new Dimension(width+10,height+10);
    Obstacles()
    {
        this.setBackground(Color.white);
       // this.addKeyListener(this);
       // this.setFocusable(true);
       // this.setRequestFocusEnabled(true);
        setSize(mindim);
        this.setVisible(true);
    }
    public void paintComponent(Graphics g)
    {
        super.paintComponent(g); //
        g.fillRect(0, 0, 60, 30);
        g.setColor(Color.black);
        g.draw3DRect(0, 0, 60, 30, true);
        g.setColor(Color.black);
    }
 }

所以你可以看到组件的高度是 30，宽度是 60，但是上图显示的还不到它的一半!

我能做些什么来让这两个 JPanels 混合在一起吗？顺便一提，我之前尝试过使用 BoxLayout 但它没有用。是有什么问题还是我的 IDE 没有正常工作？欢呼并感谢您的精彩回复。我只是一个入门的 gui 程序员，我真的不知道如何处理事情。是的，如果你想问完整的代码，我会编辑它。 :)

Answer 1

最后，你提出一个要求:

I was just trying to put an image of a rectangle inside a jframe together with another Jpanel of an image of a circle. to see if how i would be that far in mixing two Jpanels together without overlapping.

是的，这可以做到，比如通过使用 JLayeredPane，您可以将一个 JPanel 叠加在另一个之上，但是您需要确保上面的 JPanel 不是不透明的 (setOpaque(false)) .

但话虽如此，我仍然坚持我的意见，即您看起来是在做错事。您不应该为绘制一件事 创建一个 JPanel 并尝试组合多个 JPanel，因为这会导致困惑。相反，你应该考虑创建一个绘图 JPanel，并给它逻辑对象，比如非 GUI Obstacle 对象，将它们放在一个集合中，例如 ArrayList，然后在绘图 JPanel 中，遍历绘图 JPanel 的 paintComponent 方法中的所有 Obstacles , 按照指示绘制每个障碍物。

---

编辑
例如:

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.util.ArrayList;
import java.util.List;

import javax.swing.*;

public class ObstacleDrawer extends JPanel {
   private static final int PREF_W = 800;
   private static final int PREF_H = PREF_W;
   private List<Obstacle> obstacleList = new ArrayList<>();

   public ObstacleDrawer() {

   }

   public void addObstacle(Obstacle obstacle) {
      obstacleList.add(obstacle);
   }

   @Override
   public Dimension getPreferredSize() {
      if (isPreferredSizeSet()) {
         return super.getPreferredSize();
      }
      return new Dimension(PREF_W, PREF_H);
   }

   @Override
   protected void paintComponent(Graphics g) {
      super.paintComponent(g);
      Graphics2D g2 = (Graphics2D) g;
      // smooth out the drawing
      g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
            RenderingHints.VALUE_ANTIALIAS_ON);

      // iterate through the obstacle list, drawing each obstacle
      for (Obstacle obstacle : obstacleList) {
         obstacle.draw(g2);
      }
   }

   private static void createAndShowGui() {
      ObstacleDrawer mainPanel = new ObstacleDrawer();

      mainPanel.addObstacle(new CircleObstacle(new Point(200, 200), 100, Color.red));
      mainPanel.addObstacle(new CircleObstacle(new Point(400, 300), 150, Color.blue));

      JFrame frame = new JFrame("ObstacleDrawer");
      frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
      frame.getContentPane().add(mainPanel);
      frame.pack();
      frame.setLocationByPlatform(true);
      frame.setVisible(true);
   }

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

interface Obstacle {
   public Point getCenter();
   public void setCenter(Point center);
   public int getWidth();
   public void setWidth(int width);
   public Color getColor();
   public void setColor(Color color);
   public void draw(Graphics2D g2);
}

class CircleObstacle implements Obstacle {
   private Point center;
   private int width;
   private Color color;

   public CircleObstacle(Point center, int width, Color color) {
      this.center = center;
      this.width = width;
      this.color = color;
   }

   @Override
   public Point getCenter() {
      return center;
   }

   @Override
   public void setCenter(Point center) {
      this.center = center;
   }

   @Override
   public int getWidth() {
      return width;
   }

   @Override
   public void setWidth(int width) {
      this.width = width;
   }

   @Override
   public Color getColor() {
      return color;
   }

   @Override
   public void setColor(Color color) {
      this.color = color;
   }

   @Override
   public void draw(Graphics2D g2) {
      Color oldColor = g2.getColor();
      g2.setColor(color);
      int x = center.x - width / 2;
      int y = center.y - width / 2;
      int height = width;
      g2.fillOval(x, y, width, height);
      g2.setColor(oldColor);
   }
}