inputStream fail to fetch csvfile android

Question

I struggled for 3 days with loading the csv file on the android. I have created the raw folder and added the brojler.csv file to it. However, every time I try to load it, I get a NullPointerException error. I tried to read and solve it myself, but based on this topic (What is a NullPointerException, and how do I fix it?) I can not find a reason. I am a freshman in android, however, I think that all variables have been defined well. Strangely, in another application the same code works and correctly loads the file.

Brojler.csv have 9 columns and 12 rows.

In addition, I changed the way of declaring the lists like below but without success

List<String> ingredients = new ArrayList<>();
List<String> em = new ArrayList<>();
List<String> bo = new ArrayList<>();
And so on,

My code:

package com.example.nick.calcy;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

public class Mix extends AppCompatActivity {
    InputStream inputStream;
    List<String> ingredients,em,bi,ws,ca,fs,na,L,M = new ArrayList<>();
    String[] ids;
    EditText et1,et2,et3,et4,et5,et6,et7;
    Float sum;
    Button buttonSum;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_mix);

        et1 = findViewById(R.id.editText11);

        et2 = findViewById(R.id.editText12);

        et3 = findViewById(R.id.editText13);

        et4 = findViewById(R.id.editText14);

        et5 = findViewById(R.id.editText15);

        et6 = findViewById(R.id.editText16);

        et7 = findViewById(R.id.editText17);

        buttonSum = findViewById(R.id.button11);

        inputStream = getResources().openRawResource(R.raw.brojler);

        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
        try {
            String csvLine;
            while ((csvLine = reader.readLine()) != null) {

                ids=csvLine.split(",");
                try{
                    ingredients.add(ids[0]);
                    em.add(ids[1]);
                    bi.add(ids[2]);
                    ws.add(ids[3]);
                    ca.add(ids[4]);
                    fs.add(ids[5]);
                    na.add(ids[6]);
                    L.add(ids[7]);
                    M.add(ids[8]);

                }catch (Exception e){
                    Log.e("Unknown error",e.toString());
                }
            }

        }
        catch (IOException ex) {
            throw new RuntimeException("Error in reading CSV file: "+ex);
        }


        buttonSum.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                if(et1.getText().toString().trim().length() == 0 ||
                        et2.getText().toString().trim().length() == 0 ||
                        et3.getText().toString().trim().length() == 0 ||
                        et4.getText().toString().trim().length() == 0 ||
                        et5.getText().toString().trim().length() == 0 ||
                        et6.getText().toString().trim().length() == 0 ||
                        et7.getText().toString().trim().length() == 0) {
                    CharSequence text = "Blank fields detected";
                    Toast.makeText(getApplicationContext(), text, Toast.LENGTH_LONG).show();
                }
                else{
                    Intent i = new Intent(getApplicationContext(),Summary.class);
                    Float x1 = Float.parseFloat(et1.getText().toString());
                    Float x2 = Float.parseFloat(et2.getText().toString());
                    Float x3 = Float.parseFloat(et3.getText().toString());
                    Float x4 = Float.parseFloat(et4.getText().toString());
                    Float x5 = Float.parseFloat(et5.getText().toString());
                    Float x6 = Float.parseFloat(et6.getText().toString());
                    Float x7 = Float.parseFloat(et7.getText().toString());

                    sum = x1+x2+x3+x4+x5+x6+x7;

                    i.putExtra("x1", x1);
                    i.putExtra("x2", x2);
                    i.putExtra("x3", x3);
                    i.putExtra("x4", x4);
                    i.putExtra("x5", x5);
                    i.putExtra("x6", x6);
                    i.putExtra("x7", x7);

                    if (sum == 100){
                        startActivity(i);
                    } else{
                        CharSequence text = "Sum must equal 100%";
                        Toast.makeText(getApplicationContext(), text, Toast.LENGTH_LONG).show();
                    }
                }}
        });
    }
}

My errors:

E/Unknown error: java.lang.NullPointerException: Attempt to invoke interface method 'boolean java.util.List.add(java.lang.Object)' on a null object reference
I/chatty: uid=10083(u0_a83) com.example.nick.calcy identical 1 line
E/Unknown error: java.lang.NullPointerException: Attempt to invoke interface method 'boolean java.util.List.add(java.lang.Object)' on a null object reference
E/Unknown error: java.lang.NullPointerException: Attempt to invoke interface method 'boolean java.util.List.add(java.lang.Object)' on a null object reference
I/chatty: uid=10083(u0_a83) com.example.nick.calcy expire 7 lines
E/Unknown error: java.lang.NullPointerException: Attempt to invoke interface method 'boolean java.util.List.add(java.lang.Object)' on a null object reference

I suppose that the problem may be the level of access to the file. In a working application, i use the code in main_activity, and in another app it fails cuz it's called in another (not main) activity.

Help would be really appreciated

TheRealChx101 · Accepted Answer · 2018-09-08T22:38:30.383

The NullPointerException is telling you that something is null. i.e it does not reference a valid instance.

From the looks of things you need to initialize your lists. I don't see anywhere where you're initializing them. I also find it odd that Android Studio lint didn't warn you of a possible null variable, assuming that's what you're using.

Ok, here it is:

List<String> ingredients = new ArrayList<>(),
em = new ArrayList<>(),
bi = new ArrayList<>(),
ws = new ArrayList<>(),
ca = new ArrayList<>(),
fs = new ArrayList<>(),
na = new ArrayList<>(),
L = new ArrayList<>(),
M = new ArrayList<>();

Additionally, check if the rows contain the expected number of columns; that is, check whether the ids array has all the elements you need unless you are certain all rows do.

Also, I'm pretty sure there's a better way of doing what you're doing. You could also look into using Gson/JSON if you have control of the data.

inputStream fail to fetch csvfile android

1 Answers1