Android: How to implement Parcelable to my objects? [duplicate]

Answer 1

You need to implement the Parcelable interface

public class ConstantData implements Parcelable {

    public void writeToParcel(Parcel out, int flags) {
        out.writeString(project_title);
    ....
        out.writeString(country);
        out.writeList(projectsList); // <<--
    }

    private ConstantData(Parcel in) {
        project_title = in.readString();
        ....
        country = in.readString();
        projectsList = in.readList();

I think for the writing of the projectsList to work, the Project class also needs to implement Parcelable.

See e.g. this class for an example.