Converting String to Double in Android

Question

Trying to get double values from an EditText and manipulate them before passing them to another Intent. Not using primitive data type so I can use toString methods.

Problem is when I include the protein=Double.valueOf(p).doubleValue(); style commands, the program force closes immediately without leaving any info in the logcat.If I comment them out and set some dummy data like protein = 1.0; it works with no problems. Same happens with primitive data types and parse double. This code works perfectly with dummy data in normal java. What am I doing wrong?

EditText txtProt, txtCarb, txtFat, txtFiber, txtPoints;
String p, c, f, fi;
Double protein, carbs, fat, fiber;
double temp;
Integer points;

@Override
public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     Log.v("Create Prompt", "ready for layout");
     setContentView(R.layout.main);
     Log.v("Layout Created", "ready for variable assignment");
     txtProt = (EditText) findViewById(R.id.Protein);
     txtCarb = (EditText) findViewById(R.id.Carbs);
     txtFat = (EditText) findViewById(R.id.Fat);
     txtFiber = (EditText) findViewById(R.id.Fiber);
     txtPoints = (EditText) findViewById(R.id.Points);
     btnCalc = (Button) findViewById(R.id.Calc);
     Log.v("Variables Assigned", "ready for double assignment");

     p = txtProt.getText().toString();
     c = txtCarb.getText().toString();
     f = txtFat.getText().toString();
     fi = txtFiber.getText().toString();


     protein=Double.valueOf(p).doubleValue();
     carbs=Double.valueOf(c).doubleValue();
     fat=Double.valueOf(f).doubleValue();
     fiber=Double.valueOf(fi).doubleValue();
     Log.v("Doubles parsed", "ready for calculations");
     //these are the problem statements

     protein = 1.0;
     carbs = 1.0;
     fat = 1.0;
     fiber = 1.0;

     protein *= 16;
     carbs *= 19;
     fat *= 45;
     fiber *= 14;

     temp = protein + carbs + fat - fiber;
     temp = temp/175;

     points = new Integer((int) temp);

user_7761063 · Answer

I had the same issue, but I have just figured out that :

parsing the EditText value in the Oncreate method caused the app to crash because when the app starts, there are no values to parse or maybe the placeholders which are letter.

My code:

package com.example.herodav.volumeapp;

import android.renderscript.Double2;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.*;
import android.widget.*;

import org.w3c.dom.Text;

public class MainActivity extends AppCompatActivity {

    EditText height, length, depth;
    TextView volume;
    double h,l,d,vol;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        height = (EditText)findViewById(R.id.h);
        length = (EditText)findViewById(R.id.l);
        depth = (EditText)findViewById(R.id.d);
        volume = (TextView)findViewById(R.id.v);

        Button btn = (Button)findViewById(R.id.btn);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                calculateVolume();
                volume.setText("Volume = " + String.valueOf(vol));
            }
        });
    }

    public void calculateVolume(){
        h = Double.parseDouble(height.getText().toString());
        l = Double.parseDouble(length.getText().toString());
        d = Double.parseDouble(depth.getText().toString());
        vol = h*l*d;
    }
}

I

user_12280944 · Answer

double d = Double.parseDouble(aString);

Make sure the variable aString contains only numerical digits. It may have a '+' or '-' sign at the beginning.

I was using a string having quotations in it and got an error.

Converting String to Double in Android

9 Answers