java.lang.NullPointerException:Attempt to invoke virtual method on a null object reference

Question

i'm working on an app where the user can display movie posters in a grid view and see movie details..my problem is that when i run the app and click on a poster i get this error Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Long com.example.android.movies.Movies.getMposter_id()' on a null object reference at this line id = movie.getMposter_id();

i don't know how can i solve it. Sorry if I'm incompetent but I couldn't understand how to fix it. Thanks.

here is DetailsFragment.java

package com.example.android.movies;

import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ExpandableListView;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.ToggleButton;

import com.squareup.picasso.Picasso;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import static com.example.android.movies.R.id.favoriteButton;
import static com.example.android.movies.R.id.iv_poster;


/**
 * A placeholder fragment containing a simple view.
 */
public class DetailsFragment extends Fragment{


    Long id;
    String title, overview, poster, date;
    String vote;
    ImageView posterIV;
    TextView titleTV, dateTV, overviewTV, voteTV;
    static Context mContext;

    ExpandableListAdapter listAdapter;
    static ExpandableListView expListView;
    static List<String> listDataHeader;
    static HashMap<String, List<Trailers>> listDataChild;

    static ArrayList<Trailers> arrTrailers;
    static ArrayList<Trailers> arrReviews;

    ToggleButton favorite;
    private MoviesDB db;

    Trailers t;


    public static DetailsFragment newInstance() {
        return new DetailsFragment();
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_details, container, false);

        // get the listview
        expListView = (ExpandableListView) rootView.findViewById(R.id.lvExp);

        // receiving intent

        Intent gIntent = getActivity().getIntent();
        Movies movie = null;
        if (gIntent != null && gIntent.hasExtra("movie")) {
            movie = gIntent.getParcelableExtra("movie");


            id = movie.getMposter_id();

            title = movie.getMtitle();
            titleTV = (TextView) rootView.findViewById(R.id.tv_title);
            titleTV.setText(title);

            date=movie.getMdate();
            dateTV = (TextView) rootView.findViewById(R.id.tv_date);
            dateTV.setText(date);

            vote=String.valueOf(movie.getMvote());
            voteTV= (TextView) rootView.findViewById(R.id.tv_vote);
            voteTV.setText(vote);


            overview=movie.getMoverview();
            overviewTV = (TextView) rootView.findViewById(R.id.tv_overview);
            overviewTV.setText(overview);

            poster = movie.getMposter_path();
            posterIV = (ImageView) rootView.findViewById(iv_poster);
            Picasso.with(getActivity())
                    .load("http://image.tmdb.org/t/p/w185".concat(poster)).into(posterIV);

            favorite= (ToggleButton) rootView.findViewById(favoriteButton);

        }
        favorite.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                db.insert(id,title,poster,date, Double.parseDouble(vote),overview,t.getContent1());

            }
        });

        return rootView;
    }

    private void settingAdapter() {
        // preparing list data
        prepareListData();

        listAdapter = new ExpandableListAdapter(getActivity(), listDataHeader, listDataChild);

        // setting list adapter
        expListView.setAdapter(listAdapter);
    }

    /*
     * Preparing the list data
     */
    private void prepareListData() {
        listDataHeader = new ArrayList<String>();
        listDataChild = new HashMap<String, List<Trailers>>();


        // Adding child data
        listDataHeader.add("Reviews");
        listDataHeader.add("Trailers");

        listDataChild.put(listDataHeader.get(0), arrReviews); // Header, Child data
        listDataChild.put(listDataHeader.get(1), arrTrailers);
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        mContext=getActivity();

        new TrailersFetcher(getActivity(), id,this).execute();
    }

    public void updateTrailers(ArrayList<Trailers> trailers){

        arrTrailers = new ArrayList<>();
        for (int i = 0; i <trailers.size() ; i++) {
            arrTrailers.add(trailers.get(i));

        }
        new ReviewsFetcher(mContext, id,this).execute();
    }

    public void updateReviews(ArrayList<Trailers> reviews){
        arrReviews = new ArrayList<>();

        for (int i = 0; i <reviews.size() ; i++) {
            arrReviews.add(reviews.get(i));

        }

        settingAdapter();
    }
}

here is Movies.java

package com.example.android.movies;

import android.os.Parcel;
import android.os.Parcelable;

/**
 */
public class Movies implements Parcelable {
    String Mposter_path;
    Long Mposter_id;
    String Mtitle;
    String Moverview;
    String Mdate;
    Double Mvote;
    Long id;

    public Movies(String mposter_path, Long mposter_id, String mtitle,
                  String moverview, String mdate, Double mvote) {
        Mposter_path = mposter_path;
        Mposter_id = mposter_id;
        Mtitle = mtitle;
        Moverview = moverview;
        Mdate = mdate;
        Mvote = mvote;
    }

    public Movies() {

    }

    public String getMposter_path() {
        return Mposter_path;
    }

    public Long getMposter_id() {return Mposter_id;}

    public String getMtitle() {
        return Mtitle;
    }

    public String getMoverview() {
        return Moverview;
    }

    public String getMdate() {
        return Mdate;
    }

    public Double getMvote() {
        return Mvote;
    }


    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(this.Mposter_path);
        dest.writeValue(this.Mposter_id);
        dest.writeString(this.Mtitle);
        dest.writeString(this.Moverview);
        dest.writeString(this.Mdate);
        dest.writeValue(this.Mvote);
    }

    private Movies(Parcel in) {
        this.Mposter_path = in.readString();
        this.Mposter_id = (Long) in.readValue(Long.class.getClassLoader());
        this.Mtitle = in.readString();
        this.Moverview = in.readString();
        this.Mdate = in.readString();
        this.Mvote = (Double) in.readValue(Double.class.getClassLoader());
    }

    public static final Parcelable.Creator<Movies> CREATOR = new Parcelable.Creator<Movies>() {
        @Override
        public Movies createFromParcel(Parcel source) {
            return new Movies(source);
        }

        @Override
        public Movies[] newArray(int size) {
            return new Movies[size];
        }
    };
}

MovieAdapter.java

package com.example.android.movies;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;

import com.squareup.picasso.Picasso;

import java.util.ArrayList;

/**
 *
 */
public class MovieAdapter extends BaseAdapter{
    ArrayList<Movies> MovieList=new ArrayList<Movies>();
    Context mContext;

    public MovieAdapter(Context context,ArrayList<Movies> movieArrayList) {
        this.mContext=context;
        this.MovieList=movieArrayList;
    }

    @Override
    public int getCount() {
        return MovieList == null ? 0 : MovieList.size();
    }

    @Override
    public Object getItem(int position) {
        return MovieList.get(position);
    }

    @Override
    public long getItemId(int id) {return MovieList.get(id).getMposter_id(); }

    @Override
    public View getView(int position, View ConvertedView, ViewGroup viewGroup) {
        View view=ConvertedView;
        if (view==null)
        {
            LayoutInflater inflater=(LayoutInflater)
                    mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            view=inflater.inflate(R.layout.grid_item,null);
        }
        ImageView ivMovieName= (ImageView) view.findViewById(R.id.image_view);

        Picasso.with(mContext)
                .load("http://image.tmdb.org/t/p/w185"+MovieList.get(position).getMposter_path()).into(ivMovieName);


        return view;
    }
}

`gIntent.getParcelableExtra("movie")` returns `null`. [What is a NullPointerException, and how do I fix it?](http://stackoverflow.com/q/218384/3572108) — Bona Fide, Dec 01 '16 at 18:08

score 0 · Answer 1 · answered Dec 01 '16 at 18:58

0

You may have a movie in your intent but the mPoster_id is null. You need to check that your movie has an mPoster_id that isn't null, or set it to a not null value by default.

answered Dec 01 '16 at 18:58

Will Evers

934
9
17

how can we do this please guide with some code example – Ahmad Arslan Sep 06 '18 at 12:55
Put a null check for movie.getName() and movie.getId() and dont set the test if they are null – Will Evers Sep 07 '18 at 12:11

score 0 · Answer 2 · answered Dec 01 '16 at 19:21

Where is your activity code? Did you actually put this movie object to your activity's intent like getIntent().putExtra(movie)? Looks like there is no problem with Movie class. Here is the working code I have tested: MainActivity.java:

public class MainActivity extends AppCompatActivity {

Movie movie;

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

    TextView test = (TextView) findViewById(R.id.test);

    movie = new Movie("Awesome", (long) 123);
    String about = movie.getName() + "\n" + movie.getId();
    test.setText(about);

    test.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            getIntent().putExtra("movie", movie);

            if (savedInstanceState == null)
                getSupportFragmentManager()
                        .beginTransaction()
                        .replace(R.id.container_view, new DetailFragment())
                        .commit();

        }
    });

}
}

DetailFragment.java:

public class DetailFragment extends Fragment{

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    View root = inflater.inflate(R.layout.fragment_detail,container,false);

    TextView textView = (TextView)root.findViewById(R.id.textView2);

    Movie movie = getActivity().getIntent().getParcelableExtra("movie");

    String about = movie.getName()+"\n"+movie.getId();
    textView.setText(about);

    return root;
}
}

Movie.java:

public class Movie implements Parcelable{

private Long id;
private String name;

public Movie(String n, Long i){
    name = n;
    id = i;
}

public Long getId() {
    return id;
}

public void setId(Long id) {
    this.id = id;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

protected Movie(Parcel in) {
    this.name = in.readString();
    this.id = (Long) in.readValue(Long.class.getClassLoader());
}

public static final Creator<Movie> CREATOR = new Creator<Movie>() {
    @Override
    public Movie createFromParcel(Parcel in) {
        return new Movie(in);
    }

    @Override
    public Movie[] newArray(int size) {
        return new Movie[size];
    }
};

@Override
public int describeContents() {
    return 0;
}

@Override
public void writeToParcel(Parcel parcel, int i) {
    parcel.writeString(this.name);
    parcel.writeValue(this.id);
}
}

java.lang.NullPointerException:Attempt to invoke virtual method on a null object reference

2 Answers2