帮忙!!!不明白

lmy5360

import javax.swing.*;//JComponent
import java.awt.*;//frame,layout
import java.awt.event.*;

public class Essays extends GradeActivity implements ActionListener{

        private JButton btn1,btn2;
        private JTextField F1,F2,F3,F4,F5,F6;

   Essays(){

    //create a panel with grammar,content,correctlength,spelling
        JPanel p1=new JPanel();
        p1.setLayout(new GridLayout(6,3,2,4));


        p1.add(new JLabel());
        p1.add(new JLabel());
        p1.add(new JLabel("          Grammar    "));
        p1.add(F1 = new JTextField(3));

        p1.add(new JLabel("          Content    "));
        p1.add(F2 = new JTextField(3));

        p1.add(new JLabel("          Correct length    "));
        p1.add(F3 = new JTextField(3));

        p1.add(new JLabel("          Spelling    "));
        p1.add(F4 = new JTextField(3));

    F1.setHorizontalAlignment(JTextField.RIGHT);
    F2.setHorizontalAlignment(JTextField.RIGHT);
    F3.setHorizontalAlignment(SwingConstants.RIGHT);
    F4.setHorizontalAlignment(SwingConstants.RIGHT);

    //create a panel to display total and grade
    JPanel p2=new JPanel();
        p2.setLayout(new FlowLayout(FlowLayout.CENTER,5,2));

    p2.add(new JLabel("Total"));
        p2.add(F5 = new JTextField(5));
        F5.setEditable(false);

        p2.add(new JLabel("        Grade"));
        p2.add(F6 = new JTextField(5));
        F6.setEditable(false);

    //create a panel for buttons
    JPanel p3=new JPanel();
        p3.setLayout(new FlowLayout(FlowLayout.CENTER,30,30));
        p3.add(btn1 = new JButton("Process"));
        p3.add(btn2 = new JButton("Exit"));

    //create a panel to fit in other panel
    JPanel p4=new JPanel();
    p4.setLayout(new BorderLayout());
    p4.add(p1,BorderLayout.WEST);
        p4.add(p2,BorderLayout.SOUTH);

        //add panel into frame
        add(p3,BorderLayout.SOUTH);
        add(p4,BorderLayout.CENTER);

        btn1.addActionListener(this);
        btn2.addActionListener(this);


   }

   public void actionPerformed(ActionEvent e){
         if(e.getSource()==btn1){
           double grammar=Double.parseDouble(F1.getText());
       double content=Double.parseDouble(F2.getText());
       double correctLength=Double.parseDouble(F3.getText());
       double spelling=Double.parseDouble(F4.getText());

       double total=grammar+content+correctLength+content;
       F5.setText(String.valueOf(total));

     char Grade=getGrade();
     F6.setText(String.valueOf(Grade));
     }

    else{
                        System.exit(0);
        }
}

    public static void main(String[]args){
            JFrame frame=new JFrame();
            frame.setTitle("Grade Activity");
            frame.setSize(300,320);
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            //frame.setLocationRelativeTo(null);
            frame.setVisible(true);


            }
    }




//package lab4;

public class GradeActivity{
  private double score=100;
  private char grade='A';

  public GradeActivity(){super();}

  public GradeActivity(double score, char grade){
         super();
     this.score=score;
     this.grade=grade;
  }

  public double getScore(){
    return score;
  }

  public void setScore(double score){
    this.score=score;
  }

  public char getGrade(){
    if(score>=90)
      return 'A';

    else if(score>=80)
      return 'B';

    else if(score>=70)
      return 'C';

    else if(score>=60)
      return 'D';

    else return 'E';
  }

  public void setGrade(char grade){
     this.grade=grade;
  }

  public String toString(){
     return "Total score\t: " + getScore() + "\nGrade\t\t: " + getGrade();
  }
}


//package lab4;

//import java.util.Scanner;
public class testEssays{
  public static void main(String[] args){

         //Scanner input=new Scanner(System.in);
     Essays essay1=new Essays();
     Essays essay2=new Essays(27,17.8,20,26.2);

     System.out.println(essay1);
     System.out.println();
     System.out.println(essay2);                //same with ;
                                                                                  //System.out.println(essay2.toString())


     //System.out.println("Grammar\t\t: " + essay2.getGrammar());
  }
}


C:\Users\Chan\Desktop\lab4\Essays.java:61: cannot find symbol
symbol  : method add(javax.swing.JPanel,java.lang.String)
location: class Essays
        add(p3,BorderLayout.SOUTH);
        ^
C:\Users\Chan\Desktop\lab4\Essays.java:62: cannot find symbol
symbol  : method add(javax.swing.JPanel,java.lang.String)
location: class Essays
        add(p4,BorderLayout.CENTER);
        ^
2 errors

Tool completed with exit code 1

Super-Tomato

原帖由 lmy5360 于 2009-10-5 08:45 AM 发表
那我要怎样，是不是:frame.add(p3,BorderLayout.SOUTH);
                                     frame.add(p4,BorderLayout.CENTER);?

        我的BASIC不是很好。。。不好意识！！！！！

1. 參考 frame class 所提供你的方法
2. 參考上方的增加面板方式, 然後依樣畫葫蘆即可

lmy5360

为么不能显示结果呢？

lmy5360

难道还要多一个panel？

lmy5360

那我要怎样，是不是:frame.add(p3,BorderLayout.SOUTH);
                                     frame.add(p4,BorderLayout.CENTER);?

        我的BASIC不是很好。。。不好意识！！！！！

Super-Tomato

原帖由 lmy5360 于 2009-10-5 01:16 AM 发表
import javax.swing.*;//JComponent
import java.awt.*;//frame,layout
import java.awt.event.*;

public class Essays extends GradeActivity implements ActionListener{

        private JButton btn1,btn2 ...

    //create a panel to fit in other panel
    JPanel p4=new JPanel();
    p4.setLayout(new BorderLayout());
    p4.add(p1,BorderLayout.WEST);
        p4.add(p2,BorderLayout.SOUTH);

        //add panel into frame
        add(p3,BorderLayout.SOUTH);
        add(p4,BorderLayout.CENTER);

        btn1.addActionListener(this);
        btn2.addActionListener(this);


基礎錯誤 : 沒有指定方法屬於哪個對象