Android ArrayList<MyObject> pass as parcelable

Question

Code now modified to reflect the accepted solution.

This now serves as a working example of how to pass a custom ArrayList into a DialogFragment.

I am passing an ArrayList of custom objects to a DialogFragment using a Bundle on newInstance. The arraylist is received correctly in newInstance. The call to putParcelable executes fine (no errors), but putting breakpoints in the parcelable code in the ArrayList object shows that the parcel methods are not been called when setting or getting the data.

Am i correct creating a LocalityList class for the ArrayList and making that parcelable, or should Locality class itself be parcelable ?

DialogFragment

/**
 * Create a new instance of ValidateUserEnteredLocationLocalitySelectorFragment, providing "localityList"
 * as an argument.
 */
public static ValidateUserEnteredLocationLocalitySelectorFragment newInstance(LocalityList localityList) {

    ValidateUserEnteredLocationLocalitySelectorFragment fragmentInstance = new ValidateUserEnteredLocationLocalitySelectorFragment();

    // Supply location input as an argument.
    Bundle bundle = new Bundle();
    bundle.putParcelable(KEY_LOCALITY_LIST, localityList);
    fragmentInstance.setArguments(bundle);

    return fragmentInstance;
}


/**
 * Retrieve the locality list from the bundle
 */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mLocalityList = getArguments().getParcelable(KEY_LOCALITY_LIST);
}


 @Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

    View view = inflater.inflate(R.layout.validate_user_entered_location, container, false);

    mLocalityListView = (ListView) view.findViewById(R.id.dialogLocalityListView);
    mAdapter = new SearchLocationLocalitiesListAdapter(getActivity(), mLocalityList);
    mLocalityListView.setAdapter(mAdapter);

    return view;
}

LocalityList class

import java.util.ArrayList;

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

public class LocalityList extends ArrayList<Locality> implements Parcelable {

    private static final long serialVersionUID = 663585476779879096L;

    public LocalityList() {
    }

    @SuppressWarnings("unused")
    public LocalityList(Parcel in) {
        this();
        readFromParcel(in);
    }

    private void readFromParcel(Parcel in) {
        this.clear();

        // First we have to read the list size
        int size = in.readInt();

        for (int i = 0; i < size; i++) {
            Locality r = new Locality(in.readString(), in.readDouble(), in.readDouble());
            this.add(r);
        }
    }

    public int describeContents() {
        return 0;
    }

    public final Parcelable.Creator<LocalityList> CREATOR = new Parcelable.Creator<LocalityList>() {
        public LocalityList createFromParcel(Parcel in) {
            return new LocalityList(in);
        }

        public LocalityList[] newArray(int size) {
            return new LocalityList[size];
        }
    };

    public void writeToParcel(Parcel dest, int flags) {
        int size = this.size();

        // We have to write the list size, we need him recreating the list
        dest.writeInt(size);

        for (int i = 0; i < size; i++) {
            Locality r = this.get(i);

            dest.writeString(r.getDescription());
            dest.writeDouble(r.getLatitude());
            dest.writeDouble(r.getLongitude());
        }
    }
}

Locality class

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


public class Locality implements Parcelable {

    private String mDescription;
    private double mLatitude;
    private double mLongitude;


    public Locality(String description, double latitude, double longitude) {
        super();
        this.mDescription = description;
        this.mLatitude = latitude;
        this.mLongitude = longitude;
    }

    public Locality(){
        super();
    }


    public String getDescription() {
        return mDescription;
    }

    public void setDescription(String description) {
        this.mDescription = description;
    }


    public double getLatitude() {
        return mLatitude;
    }

    public void setLatitude(double latitude) {
        this.mLatitude = latitude;
    }


    public double getLongitude() {
        return mLongitude;
    }

    public void setLongitude(double longitude) {
        this.mLongitude = longitude;
    }


    @SuppressWarnings("unused")
    public Locality(Parcel in) {
        this();
        readFromParcel(in);
    }

    private void readFromParcel(Parcel in) {
        this.mDescription = in.readString();
        this.mLatitude = in.readDouble();
        this.mLongitude = in.readDouble();
    }

    public int describeContents() {
        return 0;
    }

    public final Parcelable.Creator<Locality> CREATOR = new Parcelable.Creator<Locality>() {
        public Locality createFromParcel(Parcel in) {
            return new Locality(in);
        }

        public Locality[] newArray(int size) {
            return new Locality[size];
        }
    };


    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(mDescription);
        dest.writeDouble(mLatitude);
        dest.writeDouble(mLongitude);
    }
}

Answer 1

Yes, make Locality class itself Parcelable, and don't forgot to initialize

ArrayList<Locality> mList= new ArrayList<Locality>();

Answer 2

I know this question is rather old but since I originally came here looking for answers, I wanted to share my experience.

Yes, you need to implement Parcelable for your Locality class but that is it.

If your LocalityList is ONLY a wrapper for ArrayList, then you do not need it.

Just use the putParcelableArrayList method.

ArrayList<Locality> localities = new ArrayList<Locality>;
...
Bundle bundle = new Bundle();
bundle.putParcelableArrayList(KEY_LOCALITY_LIST, localities);
fragmentInstance.setArguments(bundle);

return fragmentInstance;

And retrieve it using...

localities = savedInstanceState.getParcelableArrayList(KEY_LOCALITY_LIST);

So, unless you need the custom ArrayList for some other reason, you can avoid doing any of that extra work and only implement Parcelable for your Locality class.

Answer 3

The trick i normally use is to parse the list to Json using Gson (from google). On the other side i just parte the string in Json back to a new list.

Never noticed any lag.