Lab 4 BMI Application

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Discussion

Click on the picture below to see a zoom-in view

Discussion on the codings

        //Step1: Binding java object to xml object

        //Java          //XML GUI components
        etWeight =       (EditText) findViewById(R.id.etWeight);

        etHeight =       (EditText) findViewById(R.id.etHeight);
        btnCalculate =   (Button) findViewById(R.id.btnCalculate);
        tvResult =       (TextView) findViewById(R.id.tvResult);

        //Step2: Add a listener to the button

        btnCalculate.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

               //Step3 : get the height and weight entered by the user using getText
               String height = etHeight.getText().toString();
               String weight = etWeight.getText().toString();

                //Step 4 : convert the height and weight from String to double
               double h = Double.parseDouble(height);
               double w = Double.parseDouble(weight);

               //Step 5 : Calculate the bmi
               double bmi= w/h/h;

               //Step 6 : show the bmi result to the TextView using setText
               tvResult.setText("BMI is "+bmi);

            }

        });

To express in 2 Decimal places

https://stackoverflow.com/questions/5710394/how-do-i-round-a-double-to-two-decimal-places-in-java

 double number  = 22.12345678; 

 DecimalFormat twoDForm = new DecimalFormat("#.##");
  double amount =  Double.valueOf(twoDForm.format(number));

https://onlinegdb.com/hcvwLSwgX

import java.text.DecimalFormat;
public class Main
{
	public static void main(String[] args) {
		

	 double number  = 22.12845678; 
		 
	 System.out.println("The number is "+number);    //The number is 22.12845678
         DecimalFormat twoDForm = new DecimalFormat("#.##");
         number =  Double.valueOf(twoDForm.format(number));
          
          System.out.println("The number is "+number);//The number is 22.13

          
          
	}
}

if we used System.out.println("The number is "+number);

the result will appear in the logcat as shown below: