java - 无法在另一个文本字段中添加和显示文本字段值

Question

我似乎无法添加文本字段并在显示卡路里文本字段中显示其结果。

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

此小程序在应使用浮点或 double 值的地方使用整数值。解决这个问题。

更改:

int weight, minRun, minBsktBall, hourSleep;

致:

double weight, minRun, minBsktBall, hourSleep;

& actionPerformed 应该更符合以下内容:

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)));