How to write to arraylist of two or more custom objects in Parcelable?

Question

I have browsed the question on Stack and I found no question facing the particular problem. I have a class with two arraylist of custom objects. I am not sure how to implement writeToParcel for the parent class now. One option I found were readTypedList constructor, but I cant implement it twice. There is no readTypedListArray constructor that I can create an array ans send it.

Just a reminder the object are ArrayList and there are two such objects in the parent class. The github link for reference is here.

https://github.com/legalimpurity/PopularMoviesStage2/tree/master/app/src/main/java/popularmoviesstage1/legalimpurity/com/popularmoviesstage2/objects

score 4 · Accepted Answer · answered Aug 07 '17 at 15:31

You can add customArray using following way :

In MovieObject class:

  @Expose
  private ArrayList< ReviewObject > ReviewObjs = new ArrayList< ReviewObject >();
  private ArrayList< TrailerVideoObject > TrailerVideoObjs = new ArrayList< TrailerVideoObject >();

writeToParcel() :

 public void writeToParcel(Parcel dest, int flags) {
        dest.writeTypedList(ReviewObjs);
        dest.writeTypedList(TrailerVideoObjs);
    }

and readFromParcel() :

private void readFromParcel(Parcel in) {

    ReviewObjs = new ArrayList<ReviewObject>();
    in.readTypedList(ReviewObjs, ReviewObject.CREATOR);

    TrailerVideoObjs = new ArrayList<TrailerVideoObject>();
    in.readTypedList(TrailerVideoObjs, TrailerVideoObject.CREATOR);

  }

And add following lines in CustomClasses :

for ReviewObject :

public class ReviewObject implements Parcelable {
    public static final Creator<ReviewObject> CREATOR = new Creator<ReviewObject>() {
        public ReviewObject createFromParcel(Parcel in) {
            return new ReviewObject(in);
        }

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

    };
// add other objects...
}

for TrailerVideoObject :

public class TrailerVideoObject implements Parcelable {
    public static final Creator<TrailerVideoObject> CREATOR = new Creator<TrailerVideoObject() {
        public TrailerVideoObject createFromParcel(Parcel in) {
            return new TrailerVideoObject(in);
        }

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

    };
// add other objects...
}

When you use writeTypedList second time, it overwrites the first time written TypedList. Therefore, this would not work. — legalimpurity, Aug 11 '17 at 15:20
this will definitely work, I am using same way in my own project. — NehaK, Aug 14 '17 at 12:51

Cj Js · Answer 2 · 2017-08-13T18:53:59.270

In your MovieObject.java, you can declare them as List<YOUR_CLASS> instead of ArrayList<YOUR_CLASS>.

In my code:

public class CombinedClass implements Parcelable {
    private List<Class1> class1List; 
    private List<Class2> class2List; 
    //Constructor, getter, setter, methods.
}

Both Class1 and Class2 implements Parcelable too. I'm using "auto-generated" Parcelable implementation provided by Android Studio. Here is the Parcelable implementation:

protected CombinedClass(Parcel in) {
    class1List = in.createTypedArrayList(Class1.CREATOR);
    class2List = in.createTypedArrayList(Class2.CREATOR);
}
public static final Creator<CombinedClass> CREATOR = new Creator<CombinedClass>() {
   @Override
    public CombinedClass createFromParcel(Parcel in) {
        return new CombinedClass(in);
    }

    @Override
    public CombinedClass[] newArray(int size) {
        return new CombinedClass[size];
    }
};
@Override
public int describeContents() {
    return 0;
}

@Override
public void writeToParcel(Parcel parcel, int i) {
    parcel.writeTypedList(class1List);
    parcel.writeTypedList(class2List);
}

Again, same as above. When you use writeTypedList second time, it overwrites the first time written TypedList. Therefore, this would not work. — legalimpurity, Aug 11 '17 at 15:21

score 0 · Answer 3 · answered Aug 11 '17 at 17:48

You can try below workaround in MovieObject.java

@Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeStringArray(new String[] {
                this.OrignalTitle,
                this.MoviePosterImageThumbnailUrl,
                this.PlotSynopsis,
                this.UserRating,
                this.ReleaseDate
        });

        dest.writeLongArray(new long[] {
                this._id,
                this.ApiId
        });

         ArrayList<ArrayList> temp = new List<>();
         temp.add(ReviewObjs);
         temp.add(TrailerVideoObjs);

         dest.writeTypedList(temp);


    }

How to write to arraylist of two or more custom objects in Parcelable?

3 Answers3