How to pass object (Parcelable) between Activity?

Question

Java

I have a NewsRequest object that I want to pass to the second Activity. Here is his announcement:

public class NewsRequest implements Parcelable {

    private boolean success;

    private List<News> newsList;

    protected NewsRequest(Parcel in) {
        success = in.readByte() != 0;
        in.readList(newsList, News.class.getClassLoader());
    }

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

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

    public List<News> getNewsList() {
        return newsList;
    }

    public boolean isSuccess() {
        return success;
    }

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

    @Override
    public void writeToParcel(Parcel parcel, int i) {
        parcel.writeByte((byte) (success ? 1 : 0));
        parcel.writeTypedList(newsList);
    }
}

news:

public class News implements Parcelable {

    private long date;

    private String sourceLogo;

    private String title;

    private String url;

    private String source;

    protected News(Parcel in) {
        date = in.readLong();
        sourceLogo = in.readString();
        title = in.readString();
        url = in.readString();
        source = in.readString();
    }

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

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

    public long getDate() {
        return date;
    }

    public String getSourceLogo() {
        return sourceLogo;
    }

    public String getTitle() {
        return title;
    }

    public String getUrl() {
        return url;
    }

    public String getSource() {
        return source;
    }

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

    @Override
    public void writeToParcel(Parcel parcel, int i) {
        parcel.writeLong(date);
        parcel.writeString(sourceLogo);
        parcel.writeString(title);
        parcel.writeString(url);
        parcel.writeString(source);
    }
}

This is how I pass the object:

Intent intent = new Intent(StartActivity.this, NewsActivity.class);
        intent.putExtra(NewsRequest.class.getCanonicalName(), news);
        startActivity(intent);

And this is how I take it:

NewsRequest getNews = (NewsRequest) getIntent().getParcelableExtra(
                NewsRequest.class.getCanonicalName());

The program crashes on the line (NullPointerException): in.readList(newsList, News.class.getClassLoader()); (NewsRequest.java)
Tried also in.readList(newsList, null) - same error

Answer 1

The 21st century is in the yard, I have already begun to forget how to implement parselabl. Use AutoValue.
According to NPE, there are no real out-parameters in Java. You pass a list to the method and it is filled in the method. You pass null and NPE happens. Initialize the list.