java.lang.NumberFormatException: Invalid int: “” error in Android

[Milos Gojic]

I am making an app where user must enter basic info about self.First name,second name, city and quantity that he or she wish to order.If he or she  skip one field toast will pop up with message what field is skipped. And that is ok.That works but if he skip quantity field I got error on my phone and it send user back on previously activity.When I inspect my LogCat I see error message

java.lang.NumberFormatException: Invalid int: “” error

. Now I know why that message appears.Because it expected to find Integer, if statment. but actually finds String. But do not know how to fix it.The last if/else statemen is an Issue:
Now what i tried so far:
1) Tried to set primitive int as object Integer
2)Tried to use kolicina==0;
3)Tried to use kolicina.equals(null) / kolicina.equals(0);
4)Tried to use .isEmty();

my code:

package com.dsk.android.decijisvetknjiga;

import android.content.Intent;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.Html;
import android.view.View;

import android.widget.EditText;

import android.widget.Toast;


public class Narudzbina extends AppCompatActivity {

   String porukaGreska="";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.narudzbina);

    }
    public boolean praznoPolje(EditText et){
        return (et != null && (et.equals("") || et.equals(" ")));
    }

    public void kreiranjeNarudzbine(View v) {
        EditText editTextIme = (EditText) findViewById(R.id.ime);
        String imeNarucioca = editTextIme.getText().toString();
        praznoPolje(editTextIme);


        EditText editTextPrezime = (EditText) findViewById(R.id.prezime);
        String prezimeNarucioca = editTextPrezime.getText().toString();
        praznoPolje(editTextIme);

        EditText editTelefonNarucioca = (EditText) findViewById(R.id.telefon);
        String telefonNarucioca = editTelefonNarucioca.getText().toString();
        praznoPolje(editTelefonNarucioca);

        EditText editAdresaNarucioca = (EditText) findViewById(R.id.adresa);
        String adresaNarucioca = editAdresaNarucioca.getText().toString();
        praznoPolje(editAdresaNarucioca);

        EditText editGradNarucioca = (EditText) findViewById(R.id.grad);
        String gradNarucioca = editGradNarucioca.getText().toString();
        praznoPolje(editGradNarucioca);

        EditText editKolicina = (EditText) findViewById(R.id.kolicina);
        String narucenaKolicina = editKolicina.getText().toString();
        int kolicina = Integer.parseInt(narucenaKolicina);

        praznoPolje(editKolicina);
        int cenaNarudzbine = cena(kolicina);

        String poruka = sumiranjeNarudzbine(imeNarucioca, prezimeNarucioca, telefonNarucioca, adresaNarucioca, gradNarucioca, cenaNarudzbine);
        Intent smsIntent = new Intent(Intent.ACTION_VIEW);
        smsIntent.setType("vnd.android-dir/mms-sms");
        smsIntent.putExtra("address", "[phone]");
        smsIntent.putExtra("sms_body", poruka);

        if(imeNarucioca!=null && imeNarucioca.equals("")){
            Toast.makeText(Narudzbina.this, "Unesite ime", Toast.LENGTH_LONG).show();
        }
        else if(prezimeNarucioca!=null && prezimeNarucioca.equals("")){
            Toast.makeText(Narudzbina.this,"Unesite Prezime", Toast.LENGTH_LONG).show();

        }
        else if(telefonNarucioca!=null && telefonNarucioca.equals("")){
            Toast.makeText(Narudzbina.this,"Unesite kontakt telefon", Toast.LENGTH_LONG).show();
        }
        else if(adresaNarucioca!=null && adresaNarucioca.equals("")){
            Toast.makeText(Narudzbina.this,"Unesite adresu",Toast.LENGTH_LONG).show();
        }
        else if(gradNarucioca!=null && gradNarucioca.equals("")){
            Toast.makeText(Narudzbina.this, "Navedite grad", Toast.LENGTH_LONG).show();
        }
        else if(narucenaKolicina!=null && narucenaKolicina.equals("")){
            Toast.makeText(Narudzbina.this, "Navedite zeljenu kolicinu", Toast.LENGTH_LONG).show();
        }
        else{
            startActivity(smsIntent);
        }
    }

[Ron McLeod]

You will get an exception with Integer.parseInt(narucenaKolicina) if narucenaKolicina is empty or does not represent a valid number.

You could catch the exception and take correction action by wrapping the call to parseInt in a try-catch block.  For example:

EditText editKolicina = (EditText) findViewById(R.id.kolicina);
String narucenaKolicina = editKolicina.getText().toString();
int kolicina = 0;
try {
	kolicina = Integer.parseInt(narucenaKolicina);
} catch (NumberFormatException e) {
	narucenaKolicina = ""; // this will cause the parameter check for quantity ordered to fail and pop toast
}

[Milos Gojic]

@Thank you 10000 time ))))

[Dave Tolls]

You do a lot of calls like:

praznoPolje(editTextIme);

which, looking at the method, seems to be checking the field isn't empty.
However you do nothing with the boolean result.

In fact, the check done inside there seems to be incorrect (and EditText will never be equal to a test string for example).

It looks to me like you should be correcting that method so it checks the values actually exist, and then do something with the return result.
That is, if it returns false then pop up the toast and exit.  If true, then continue to check the rest of the fields.  If all true then (and only then) deal with the data.

Currently you only validate after you start using the data.