Question

运行我的代码时收到以下错误。

错误：不兼容的类型：double无法转换为JTextField

JGrasp指出以下问题。

Programming6_4.Java:143：错误：不兼容的类型：double不能转换为JTextField averageScoreTF =（test1 * wght1 + test2 * wght2 + test3 * wght3 + test4 * wght4）; ^ 1错误

不确定为什么会标记＆＃39; +＆＃39;作为无法转换的项目。任何帮助将不胜感激。

import java.awt.*;
import java.awt.event.*;
import java.awt.FlowLayout;
import javax.swing.*;
import javax.swing.JFrame;
import javax.swing.JLabel;

   public class Programming6_4 extends JFrame
   {
      //declares variables
      private JLabel blankGrid1L, blankGrid2L, blankGrid3L, scoreL, weightL, testOneL, testTwoL, testThreeL, testFourL, averageScoreL;

      private JTextField  testOneTF, testTwoTF, testThreeTF, testFourTF, testOnewTF, testTwowTF, testThreewTF, testFourwTF, averageScoreTF;

      private JButton calculateScoreB, exitB;

      private CalculateButtonHandler cbHandler;

      private ExitButtonHandler ebHandler;

      //declare window size
      private static final int WIDTH = 400;
      private static final int HEIGHT = 200;

      public Programming6_4()
      {
         //name labels
         blankGrid1L = new JLabel ("", SwingConstants.CENTER);
         blankGrid2L = new JLabel ("", SwingConstants.CENTER);
         blankGrid3L = new JLabel ("", SwingConstants.CENTER);
         scoreL = new JLabel ("Score", SwingConstants.CENTER);
         weightL = new JLabel ("Weight", SwingConstants.CENTER);
         testOneL = new JLabel ("Test One Score: ", SwingConstants.CENTER);
         testTwoL = new JLabel ("Test Two Score: ", SwingConstants.CENTER);
         testThreeL = new JLabel ("Test Three Score: ", SwingConstants.CENTER);
         testFourL = new JLabel ("Test Four Score: ", SwingConstants.CENTER);
         averageScoreL = new JLabel ("Average Weighted Test Score: ", SwingConstants.CENTER);

         //create text fields 10 characters - Test Scores
         testOneTF = new JTextField(10);
         testTwoTF = new JTextField(10);
         testThreeTF = new JTextField(10);
         testFourTF = new JTextField(10);

         //create text fields 10 charaters - Weights
         testOnewTF = new JTextField(10);
         testTwowTF = new JTextField(10);
         testThreewTF = new JTextField(10);
         testFourwTF = new JTextField(10);
         averageScoreTF = new JTextField(10);

         //create buttons and handler
         calculateScoreB = new JButton ("Calculate");
         cbHandler = new CalculateButtonHandler();
         calculateScoreB.addActionListener(cbHandler);

         exitB = new JButton ("Exit");
         ebHandler = new ExitButtonHandler();
         exitB.addActionListener(ebHandler);

         //set grid size
         Container pane = getContentPane();
         pane.setLayout(new GridLayout (7, 3));

         //add elements to grid spaced by line
         pane.add (blankGrid1L);
         pane.add (scoreL);
         pane.add (weightL);

         pane.add (testOneL);
         pane.add (testOneTF);
         pane.add (testOnewTF);

         pane.add (testTwoL);
         pane.add (testTwoTF);
         pane.add (testTwowTF);

         pane.add (testThreeL);
         pane.add (testThreeTF);
         pane.add (testThreewTF);

         pane.add (testFourL);
         pane.add (testFourTF);
         pane.add (testFourwTF);

         pane.add (averageScoreL);
         pane.add (averageScoreTF);
         pane.add (blankGrid2L);

         pane.add (calculateScoreB);
         pane.add (blankGrid3L);
         pane.add (exitB);

         //set window title, window, and display
         setTitle ("Weighted Test Average Calculation");
         setSize (WIDTH, HEIGHT);
         setVisible (true);
         setDefaultCloseOperation (EXIT_ON_CLOSE);
         //setLayout (new Programming6_4());
      }
         //activates ActionListener
      private class CalculateButtonHandler implements ActionListener

         //Main calculation program
      {
      public void actionPerformed (ActionEvent e)  //public static void main (String[] args)
         {
            //declare varibles in 
            double test1, test2, test3, test4, wght1, wght2, wght3, wght4, avgscore /*avg1, avg2, avg3, avg4*/;

            //takes text entered by user and converts from string to decimal
            test1 = Double.parseDouble(testOneTF.getText());
            wght1 = Double.parseDouble(testOnewTF.getText());
            test2 = Double.parseDouble(testTwoTF.getText());
            wght2 = Double.parseDouble(testTwowTF.getText());
            test3 = Double.parseDouble(testThreeTF.getText());
            wght3 = Double.parseDouble(testThreewTF.getText());
            test4 = Double.parseDouble(testFourTF.getText());
            wght4 = Double.parseDouble(testFourwTF.getText());

            //calculations needed to get weighted average
            //avg1 = test1 * wght1;
            //avg2 = test2 * wght2;
            //avg3 = test3 * wght3;
            //avg4 = test4 * wght4;
            //avgscore = avg1 + avg2 + avg3 + avg4;

            averageScoreTF = (test1 * wght1 + test2 * wght2 + test3 * wght3 + test4 * wght4);
            averageScoreTF.setText("" + avgscore);
         }
      }

      private class ExitButtonHandler implements ActionListener
         {
            public void actionPerformed (ActionEvent e)
               {
                  System.exit(0);
               }
         }

      public static void maine (String[]args)
         {
            Programming6_4 testObject = new Programming6_4();
         }
   }

Answer 1

更改此行：

averageScoreTF = (test1 * wght1 + test2 * wght2 + test3 * wght3 + test4 * wght4);

为：

avgscore = (test1 * wght1 + test2 * wght2 + test3 * wght3 + test4 * wght4);

由于averageScoreTF不是数字类型（就像错误消息所说的那样），因此无法为averageScoreTF分配双精度。

Answer 2

你显然很困惑 - 双数是一个数字，jtextfield是一个GUI小部件。您很可能希望将您的号码打印到文本字段中进行演示。

错误：不兼容的类型：double无法转换为JTextField

2 个答案: