Question

// DrawPanelTest.java                             
// Application to display a DrawPanel.
import javax.swing.JFrame;

public class DrawPanelTest {

public static void main( String[] args ) {


// create a panel that contians our drawing
DrawPanel panel = new DrawPanel();
// create a new frame to hold the panel
JFrame application = new JFrame();

// set the frame to exit when it is close
   application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE);

    application.add( panel ); // add the panel to the frame
    application.setSize( 250, 250 ); // set tje size of the frame
    application.setVisible( true ); // make the frame visible
 } // end main\
} // end class DrawPanelTest


import java.awt.Graphics;
import javax.swing.JPanel;

public class DrawPanel extends JPanel {
 //int for whole class
 private int N;

 // constructor
 public DrawPanel(int numLines)
 {
     N = numLines;
 } // end constructor

   // draws an numLines from the corners of the panel
  public void paintComponent(Graphics g)
  {
     // call paintComponent to ensurethe angle displays
     super.paintComponent(g);

     int width = getWidth(); // total width
     int height = getHeight(); // total height

     // draws (N + 1) lines with equal spacing
     if (N > 0) {
         for (int counter = 0; counter <= N; counter++) {
             g.drawLine(0, height / 2, width, counter * height / N);

         }
     }
 }

} 遇到错误有困难并且不确定该怎么办或如何解决该错误需要帮助，谢谢

C：\ Users \ MAC> cd桌面

C：\ Users \ MAC \ Desktop> javac DrawPanel.java

C：\ Users \ MAC \ Desktop> javac DrawPanelTest.java DrawPanelTest.java:11：错误：类DrawPanel中的构造函数DrawPanel无法应用于给定类型； DrawPanel面板= new DrawPanel（）; ^ 要求：int 找到：没有参数原因：实际和正式论点清单的长度不同 1个错误

C：\ Users \ MAC \ Desktop>

Answer 1

要么创建一个无参数的构造函数，要么在调用类时传递参数，如下所示：-

 public DrawPanel()
 {
     N = 1;// if you want to assign some default value
 }

使用以下参数运行：-

javac Arguments.java
java Arguments arg0 arg1 arg2

编译此文件有困难，我遇到一个错误，但是我不确定该怎么办

1 个答案: