Error in list adapter : Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference

Question

I have this error:

java.lang.NullPointerException: Attempt to invoke virtual method 'boolean 
java.lang.String.equals(java.lang.Object)' on a null object reference 

Binary XML file line #0: Attempt to invoke virtual method 'boolean 
java.lang.String.equals(java.lang.Object)' on a null object reference

I saw many examples of codes but there is no difference.

the error happened in this line :

row = inflater.inflate(R.layout.list_item, parent, false);

any suggestion, please?

@Override
public View getView(int position, View row, ViewGroup parent){
    DataHandler handler = new DataHandler();
    try {
       if (row == null) {
         LayoutInflater inflater = (LayoutInflater) this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
         row = inflater.inflate(R.layout.list_item, parent, false);
         handler.poster = (ImageView) row.findViewById(R.id.movieImage);
         handler.title = (TextView) row.findViewById(R.id.movieTitle);
         handler.rating = (TextView) row.findViewById(R.id.movieRating);
         row.setTag(handler);
        } else {
            handler = (DataHandler) row.getTag();
        }

        MovieDataProvider dataProvider;
        dataProvider = (MovieDataProvider) this.getItem(position);
        handler.poster.setImageResource(dataProvider.getMovie_poster());
        handler.title.setText(dataProvider.getMovie_title());
        handler.rating.setText(dataProvider.getMovie_rating());
    }
    catch (Exception ex){
        Toast.makeText(getContext(),ex.getMessage(),Toast.LENGTH_LONG).show();
    }
    return row;
}

XML (list_item)

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="80dp"
android:background="#000">
<ImageView
    android:id="@+id/movieImage"
    android:layout_width="80dp"
    android:layout_height="75dp"
    android:layout_alignParentStart="true"
    android:layout_alignParentTop="true"
    android:contentDescription=""
    android:src="@drawable/movie_0" />

<TextView
    android:id="@+id/movieTitle"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_marginLeft="10dp"
    android:layout_toEndOf="@+id/movieImage"
    android:text="movie name"
    android:textColor="#ff2e5f"
    android:textSize="16sp"
    android:textStyle="bold" />

<TextView
    android:id="@+id/movieRating"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/movieTitle"
    android:layout_marginLeft="10dp"
    android:layout_toEndOf="@+id/movieImage"
    android:text="Rating"
    android:textColor="@android:color/holo_blue_dark"
    android:textSize="12sp"
    android:typeface="sans" />

<view
    android:layout_width="match_parent"
    android:layout_height="2dp"
    android:background="@android:color/background_light"
    android:layout_below="@+id/movieImage">
</view>
</RelativeLayout>

The whole code of adapter

import android.content.Context;
import android.support.annotation.NonNull;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.List;



public class MovieAdapter extends ArrayAdapter {
public MovieAdapter(@NonNull Context context, int resource) {
    super(context, resource);
}

List list = new ArrayList();


static class DataHandler{
    ImageView poster;
    TextView title;
    TextView rating;
}

public void add(Object object){
    super.add(object);
    list.add(object);
}

public int getCount(){
    return this.list.size();
}

public Object getItem(int position){
    return this.list.get(position);
}


@Override
public View getView(int position, View row, ViewGroup parent){
    DataHandler handler = new DataHandler();

    if (row == null) {
         LayoutInflater inflater = (LayoutInflater) this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
         row = inflater.inflate(R.layout.list_item, parent, false);
         handler.poster = (ImageView) row.findViewById(R.id.movieImage);
         handler.title = (TextView) row.findViewById(R.id.movieTitle);
         handler.rating = (TextView) row.findViewById(R.id.movieRating);
         row.setTag(handler);
        } else {
            handler = (DataHandler) row.getTag();
        }

    MovieDataProvider dataProvider;
    dataProvider = (MovieDataProvider) this.getItem(position);
    handler.poster.setImageResource(dataProvider.getMovie_poster());
    handler.title.setText(dataProvider.getMovie_title());
    handler.rating.setText(dataProvider.getMovie_rating());

    return row;
}
}

error comes from this line row = inflater.inflate(R.layout.list_item, parent, false); — Mohammad Sufian Al-Omar, Jan 04 '18 at 08:29
@Noise Generator it is not duplicate of regular NullPointerException, it is not calling method on null Object, so you marked it as duplicate wrongly, and specified wrong post — Misha Akopov, Jan 04 '18 at 09:22
@MishaAkopov That's YOUR opinion. Every NPE is the very same thing. I'm tired to say that. An object has been referenced, without having been instanced. And this actually IS the case. — Phantômaxx, Jan 04 '18 at 09:28
@Noise Generator I know what is NPE. Mohammad Saffarini didn't instantiate any objects, it was XML problem. See solution, it has nothing to do with java code or creating objects or having them null - it is internal Android exception while parsing wrong xml layout. — Misha Akopov, Jan 04 '18 at 09:32
`... it was XML problem ... it is internal Android exception while parsing wrong xml layout...` **NO, it was an NPE**, as correctly reported in the logcat: The OP was trying to use a non-existing object! `view` wasn't a valid object to use! Hope it's clear now. — Phantômaxx, Jan 04 '18 at 09:41
Yes it is NPE, but it is not duplicate of question you specified. Answers of your specified question doesn't help with this question — Misha Akopov, Jan 04 '18 at 10:25
The duplicate helps understanding NPEs in general, which is what helps in deep learning how to handle them. — Phantômaxx, Jan 04 '18 at 12:10

score 5 · Accepted Answer · answered Jan 04 '18 at 08:30

5

The problem is this:

<view
    android:layout_width="match_parent"
    android:layout_height="2dp"
    android:background="@android:color/background_light"
    android:layout_below="@+id/movieImage">
</view>

<view> starts with small letter :) You need <View>

Also see this:

Explaination here

answered Jan 04 '18 at 08:30

Misha Akopov

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Thank you Mish, it's working now, I am very shy because of this, I didn't notice that. :) – Mohammad Sufian Al-Omar Jan 04 '18 at 08:34
@MohammadSaffarini , that happens sometimes :) No problem, it is an experience – Misha Akopov Jan 04 '18 at 08:35

score 1 · Answer 2 · answered Jan 04 '18 at 08:31

the object that you try to use equals on is nll that's why you get the error :

yourObject.equals("something");

yourObject is null. if you assing a value for it it will be gone , or you can check if it's null first or use try catch block , here an example :

if(yourObject != null){

        //your code here
        }

OR:

   try{

    if(yourObject.equals("something")){

 }

    }catch(NullPointerException exNull){

// here catch your exception 

}

Error in list adapter : Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference

2 Answers2