Read and write an ArrayList of ArrayLists containing Parcelable Objects to pass in an Intent

android, android-intent, arraylist, java, parcelable

Solution

If your code is as posted, then you're just missing the initialization of the ArrayLists, i.e.

private Timetable(Parcel in)
{
    // readTypeList() needs an existing List<> to load.
    timetable = new ArrayList<Lap>();
    loggedLocations = new ArrayList<Location>();

    actLap          = in.readInt();
    in.readTypedList(timetable, Lap.CREATOR);
    in.readTypedList(loggedLocations, Location.CREATOR);
    ...

Problem

I just changed all serializable classes in my project to parcelable classes. Everything is working fine, except for that one class which is made of an ArrayList containing another ArrayList. I already debugged. There is no error when writing this ArrayList. But I get an error while reading it. This is the class where the error happens: ``` public class Timetable implements Parcelable { private int actLap = 0; private ArrayList<Lap> timetable; private ArrayList<Location> loggedLocations; private Date startTime; ... ... public void writeToParcel(Parcel out, int flags) { out.writeInt(actLap); out.writeTypedList(timetable); //no error here out.writeTypedList(loggedLocations); ... ... private Timetable(Parcel in) { actLap = in.readInt(); in.readTypedList(timetable, Lap.CREATOR); //error after this line in.readTypedList(loggedLocations, Location.CREATOR); startTime = (Date)in.readSerializable(); bestLap = in.readParcelable(Lap.class.getClassLoader()); track = in.readParcelable(Track.class.getClassLoader()); description = in.readString(); } ``` Here are the other classes: ``` public class Lap implements Parcelable { private ArrayList<Time> sectorTimes = new ArrayList<Time>(); private Time laptime; ... ... public void writeToParcel(Parcel out, int flags) { out.writeTypedList(sectorTimes); out.writeParcelable(laptime,flags); } public static final Parcelable.Creator<Lap> CREATOR = new Parcelable.Creator<Lap>() { public Lap createFromParcel(Parcel in) { return new Lap(in); } public Lap[] newArray(int size) { return new Lap[size]; } }; private Lap(Parcel in) { in.readTypedList(sectorTimes, Time.CREATOR); laptime = in.readParcelable(Time.class.getClassLoader()); } ``` And this class: ``` public class Time implements Parcelable { private long timeLong; private String timeString;... ... public void writeToParcel(Parcel out, int flags) { out.writeLong(timeLong); out.writeString(timeString); } public static final Parcelable.Creator<Time> CREATOR = new Parcelable.Creator<Time>() { public Time createFromParcel(Parcel in) { return new Time(in); } public Time[] newArray(int size) { return new Time[size]; } }; private Time(Parcel in) { timeLong = in.readLong(); timeString = in.readString(); } ``` Like I already said, everything works fine (there are more Parcelable classes which I pass with intents (including a single ArrayList) and which I save in files). So can you guys help me to write and read that double ArrayList? Thanks in advance

Original source