Java GUI BMI计算器将Infinity作为BMI返回

package business;

/**
 *
 * @author: Christopher Brookens
 */
public class HealthProfile 
{

    /**
     * @param args the command line arguments
     */
    //declare class variables
    private int age;
    private double height, heightFt, heightIn, weight, BMI, maxHR;
    private String name, category;
   
    //parameterized constructor
    public HealthProfile(String name, int age, double heightFt, double heightIn, double weight)
    {
        this.name = name;
        this.age = age;
        this.heightFt = heightFt;
        this.heightIn = heightIn;
        this.weight = weight;
        
    }
    //default constructor
    public HealthProfile()
    {
    	this("",0,0,0,0);
    }
    //access modifiers
    public void setName(String name)
    {
        this.name = name;
    }
    public String getName()
    {
        return name;
    }
    public void setAge(int age)
    {
        this.age = age;
    }
    public int getAge()
    {
        return age;
    }
    public void setHeightFt(double heightFt)
    {
    	this.heightFt = heightFt;
    }
    public double getHeightFt()
    {
    	return heightFt;
    }
    public void setHeightIn(double heightIn)
    {
    	this.heightIn = heightIn;
    }
    public double getHeightIn()
    {
    	return heightIn;
    }
    public void setHeight(double height) 
	{
		this.height = height;	
	} 
    public double getHeight()
    {
    	height = heightIn + heightFt * 12;	
    	return height;
    }
    public void setWeight(double weight)
    {
        this.weight = weight;
    }
    public double getWeight()
    {
        return weight;
    }
   
    public double getBMI()
    {
        BMI = weight * 703 / (height * height);
        return BMI;
    }
   
    public double getMaxHR()
    {
        maxHR = 220 - age;
        return maxHR;
    }
    public String getCategory()
    {
        if (BMI < 18.5)
            category = "Underweight";
        else if (BMI >= 18.5 && BMI <= 24.9)
            category = "Normal";
        else if (BMI >= 25 && BMI <= 29.9)
            category = "Overweight";
        else
            category = "Obese";
        return category;
    }
	
	
    
    
    
}

package presentation;

import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JTextField;

import business.HealthProfile;

public class HealthProfile_GUI extends JFrame implements ActionListener 
{

		private JTextField txtName = new JTextField(25);
		private JTextField txtAge = new JTextField(3);
		private JTextField txtHeightFt = new JTextField(1);
		private JTextField txtHeightIn = new JTextField(2);
		private JTextField txtWeight = new JTextField(6);
		private JTextField txtBMI = new JTextField(10);
		private JTextField txtCat = new JTextField(10);
		private JTextField txtMaxHR = new JTextField(3);
		private JLabel lblName = new JLabel("Name");
		private JLabel lblAge = new JLabel("Age");
		private JLabel lblHeightIn = new JLabel("Height (Inches)");
		private JLabel lblHeightFt = new JLabel("Height (Feet)");
		private JLabel lblWeight = new JLabel("Weight");
		private JLabel lblBMI = new JLabel("BMI");
		private JLabel lblCat = new JLabel("Category");
		private JLabel lblMaxHR = new JLabel("Max Heart Rate");
		private JButton btnCalc = new JButton("Calcualte BMI");
		private JButton btnClear = new JButton("Clear");
		private HealthProfile hp;
		
		public HealthProfile_GUI()
		{
			setTitle("Health Profile");
			setSize(400,500);
			setVisible(true);
			setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
			Container c = getContentPane();
			c.setLayout(new GridLayout(9,2,10,10));
			
			c.add(lblName);
			c.add(txtName);
			c.add(lblAge);
			c.add(txtAge);
			c.add(lblHeightFt);
			c.add(txtHeightFt);
			c.add(lblHeightIn);
			c.add(txtHeightIn);
			c.add(lblWeight);
			c.add(txtWeight);
			c.add(btnCalc);
			c.add(btnClear);
			c.add(lblBMI);
			c.add(txtBMI);
			c.add(lblCat);
			c.add(txtCat);
			c.add(lblMaxHR);
			c.add(txtMaxHR);
			btnCalc.addActionListener(this);
			btnClear.addActionListener(this);
			
			
			
		}
		@Override
	
		public void actionPerformed(ActionEvent ae)
		{
			boolean notEmpty = true;
			if(hp == null)
			{
				hp = new HealthProfile();
			}
			if (ae.getSource() == btnCalc) 
			{
				System.out.println("Calculating BMI");
				
				if(txtName.getText().equals("") || txtName.getText().isEmpty()) 
				{
					JOptionPane.showMessageDialog(null,"Name is required");
					notEmpty = false;
				}
				if(txtAge.getText().equals("") || txtAge.getText().isEmpty())
				{
					JOptionPane.showMessageDialog(null,"Age is required");
					notEmpty = false;
				}
				if(txtHeightFt.getText().equals("") || txtHeightFt.getText().isEmpty()) 
				{
					JOptionPane.showMessageDialog(null,  "Height (Feet) is required");
					notEmpty = false;
				}
				if(txtHeightIn.getText().equals("") || txtHeightIn.getText().isEmpty()) 
				{
					JOptionPane.showMessageDialog(null,  "Height (Inches) is required");
					notEmpty = false;
				}
				if(txtWeight.getText().equals("") || txtWeight.getText().isEmpty()) 
				{
					JOptionPane.showMessageDialog(null,  "Weight is required");
					notEmpty = false;
				}
				if (notEmpty == true) 
				{
					hp.setName(txtName.getText());
					hp.setAge(Integer.parseInt(txtAge.getText()));
					hp.setHeightFt(Double.parseDouble(txtHeightFt.getText()));
					hp.setHeightIn(Double.parseDouble(txtHeightIn.getText()));
					hp.setWeight(Double.parseDouble(txtWeight.getText()));
					txtBMI.setText(String.format("%.2f", hp.getBMI()));
					txtCat.setText(hp.getCategory());
					txtMaxHR.setText(String.format("%.0f", hp.getMaxHR()));
					System.out.println(hp.getWeight());
					System.out.println(hp.getHeight());
					System.out.println(hp.getHeightFt());
					System.out.println(hp.getHeightIn());
					System.out.println(hp.getBMI());
				}
			}
			else if(ae.getSource() == btnClear)
			{
				txtName.setText("");
				txtAge.setText("");
				txtHeightFt.setText("");
				txtHeightIn.setText("");
				txtWeight.setText("");
				txtBMI.setText("");
				txtCat.setText("");
				txtMaxHR.setText("");
			}						
		}					
}

package presentation;

public class HealthProfileMain {
    
    public static void main(String[] args) 
    {
    	HealthProfile_GUI hp = new HealthProfile_GUI();
    	
       
    }
    
}