無法在其他文本字段中添加並顯示文本字段值

Question

我似乎無法添加文本字段並將其結果顯示在顯示卡路里文本字段中。

import java.applet.Applet; 
import java.awt.Button; 
import java.awt.Label; 
import java.awt.TextField; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 

import javax.swing.JLabel; 


public class caloriesBurnerApplet extends Applet implements ActionListener { 

    /**** 
    // 
    //Running 6 mph : 10 METS 
    //Basketball : 8 METS 
    //Sleeping: 1 METS 
    //formula for the number calories burned per minute 
    //calories/minutes = 0.0175 * MET * Weight in kilogram 
    // 
    // 1 kg = 2.2 lbs ==> 1 lb = (1/2.2) kg 
    ****/ 

    Label lbWeight, lbRun, lbBsktBall, lbSleep, lbRunningCalories, lbBsktBallCalorioes, 
    lbSleepingCalories ; 

    Button caloriesCalcBtn ; 

    TextField txtWeight, txtRun, txtBsktBall, txtSleep, txtDspyRunCalr, 
    txtDspyBsktBallCalr, txtDspySleepCalr ; 

    int weight, minRun, minBsktBall, hourSleep; 
    float caloriesRun, caloriesBsktBall, caloriesSleep, caloriesTotal; 
    String weightString, minRunString, minBsktBallString, hourSleepString; 

    private static final long serialVersionUID = 1L; 

    public caloriesBurnerApplet() 
    { 
      lbWeight = new Label("Please enter your weight", JLabel.LEFT); 
      txtWeight = new TextField(15); 
      lbRun = new Label("How long do you run for 6 mph (in minutes)", JLabel.LEFT); 
      txtRun = new TextField(15); 
      lbBsktBall = new Label("How long do you play BasketBall (in minutes)"); 
      txtBsktBall = new TextField(15); 
      lbSleep = new Label("How many hours do you sleep"); 
      txtSleep = new TextField(15); 
      caloriesCalcBtn = new Button("Calculate calories"); 
      lbRunningCalories = new Label("By Running you burnt these calories: "); 
      txtDspyRunCalr = new TextField(15); 
      lbBsktBallCalorioes = new Label("By Playing BasketBall you burnt there calories: "); 
      txtDspyBsktBallCalr = new TextField(15); 
      lbSleepingCalories = new Label("By Sleeping you burnt these calories: "); 
      txtDspySleepCalr = new TextField(15); 

    } 

    public void init() 
    { 

    add(lbWeight); 
    add(txtWeight); 
    add(lbRun); 
    add(txtRun); 
    add(lbBsktBall); 
    add(txtBsktBall); 
    add(lbSleep); 
    add(txtSleep); 
    add(caloriesCalcBtn); 
    add(lbRunningCalories); 
    add(txtDspyRunCalr); 
    add(lbBsktBallCalorioes); 
    add(txtDspyBsktBallCalr); 
    add(lbSleepingCalories); 
    add(txtDspySleepCalr); 

    } 
    @Override 

    public void actionPerformed(ActionEvent e) { 

     //calories/minutes = 0.0175 * MET * Weight in kilogram 
     // , minRunString, minBsktBallString, hourSleepString; 

     //weight = Integer.parseInt(txtWeight.getText()); 

     //minRun = Double.parseDouble(txtRun.getText()); 
     //minBsktBall = Double.parseDouble(txtBsktBall.getText()); 
     //hourSleep = Double.parseDouble(txtSleep.getText()); 
      weight = Integer.parseInt(txtWeight.getText()); 
      minRun = Integer.parseInt(txtRun.getText()); 
      minBsktBall = Integer.parseInt(txtBsktBall.getText()); 
      hourSleep = Integer.parseInt(txtSleep.getText()); 
      caloriesRun = (float) (minRun * 0.0175 * 10 * ((weight) * (1/2))); 

     if (e.getSource() == caloriesCalcBtn) 
     { 

      // can't seems to display result in the caloriesRun textfield 
      txtDspyRunCalr.setText(String.valueOf(caloriesRun)); 
     } 

    } 


} 

Answer 1

這個applet使用整數值，它應該使用float或double。解決這個問題。

變化：

int weight, minRun, minBsktBall, hourSleep; 

要：

double weight, minRun, minBsktBall, hourSleep; 

&的actionPerformed應沿的線條更：

weight = Double.parseDouble(txtWeight.getText()); 
minRun = Double.parseDouble(txtRun.getText()); 
minBsktBall = Double.parseDouble(txtBsktBall.getText()); 
hourSleep = Double.parseDouble(txtSleep.getText()); 
// That '1/2' is the real problem, it equates to '0' in integer logic! 
// caloriesRun = (float) (minRun * 0.0175 * 10 * ((weight) * (1/2))); 
caloriesRun = (float) (minRun * 0.0175 * 10d * ((weight) * (.5)));