Question

我是Java的初学者，我正在按照书中的说明进行操作。我将使用以下代码创建一个FigurePanel：

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

 public class TestFigurePanel extends JFrame{
    public TestFigurePanel() {
         setLayout(new GridLayout(2, 3, 5, 5));
         add(new FigurePanel(FigurePanel.LINE));
    }
}

但是在“添加（新的FigurePanel（FigurePanel.LINE））;”我收到以下错误：

“找不到符号：

符号：类FigurePanel

class：TestFigurePanel“

如果有人告诉我导致这个问题的原因，我会很高兴。

Answer 1

在您的包中添加此类：

import java.awt.*;

import javax.swing.JPanel;



public class FigurePanel extends JPanel {

// Define constants
public static final int LINE = 1;

public static final int RECTANGLE = 2;

public static final int ROUND_RECTANGLE = 3;

public static final int OVAL = 4;

private int type = 1;

private boolean filled;

/** Construct a default FigurePanel */

public FigurePanel() {

}

/** Construct a FigurePanel with the specified type */

public FigurePanel(int type) {

this.type = type;

}



/** Construct a FigurePanel with the specified type and filled */

public FigurePanel(int type, boolean filled) {

this.type = type;

this.filled = filled;

}



/** Draw a figure on the panel */

public void paintComponent(Graphics g) {

super.paintComponent(g);



// Get the appropriate size for the figure
int width = getSize().width;

int height = getSize().height;



switch (type) {

  case LINE: // Display two cross lines
    g.setColor(Color.BLACK);

    g.drawLine(10, 10, width - 10, height - 10);

    g.drawLine(width - 10, 10, 10, height - 10);

    break;

  case RECTANGLE: // Display a rectangle
    g.setColor(Color.BLUE);

    if (filled)

      g.fillRect((int)(0.1 * width), (int)(0.1 * height),

        (int)(0.8 * width), (int)(0.8 * height));

    else

      g.drawRect((int)(0.1 * width), (int)(0.1 * height),

        (int)(0.8 * width), (int)(0.8 * height));

    break;

  case ROUND_RECTANGLE: // Display a round-cornered rectangle
    g.setColor(Color.RED);

    if (filled)

      g.fillRoundRect((int)(0.1 * width), (int)(0.1 * height),

        (int)(0.8 * width), (int)(0.8 * height), 20, 20);

    else

      g.drawRoundRect((int)(0.1 * width), (int)(0.1 * height),

        (int)(0.8 * width), (int)(0.8 * height), 20, 20);

    break;

  case OVAL: // Display an oval
    g.setColor(Color.BLACK);

    if (filled)

      g.fillOval((int)(0.1 * width), (int)(0.1 * height),

        (int)(0.8 * width), (int)(0.8 * height));

    else

      g.drawOval((int)(0.1 * width), (int)(0.1 * height),

        (int)(0.8 * width), (int)(0.8 * height));

}

}



  /** Set a new figure type */

  public void setType(int type) {

  this.type = type;

  repaint();

}



/** Return figure type */

public int getType() {

return type;

}



/** Set a new filled property */

public void setFilled(boolean filled) {

  this.filled = filled;

  repaint();

}



/** Check if the figure is filled */

public boolean isFilled() {

return filled;

}



/** Specify preferred size */

public Dimension getPreferredSize() {

return new Dimension(80, 80);

}


}

无法让NetBeans访问Java中的“FigurePanel”

1 个答案: