How to send ArrayList() through activities

Question

I have this class:

public class FlightData implements Parcelable {
    private double x;
    private double y;
    private double time;

    FlightData(double x, double y, double time){
        this.x = x;
        this.y = y;
        this.time = time;
    }

    private FlightData(Parcel in) {
        x = in.readDouble();
        y = in.readDouble();
        time = in.readDouble();
    }


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

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeDouble(x);
        dest.writeDouble(y);
        dest.writeDouble(time);
    }

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

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

    ...
}

I try to put it into a bundle, then an intent. But I can't even retrieve it in the same activity (it throws null in the other activity, so I've tried to get it in the current - null too):

        List<FlightData> flightDataList = new ArrayList<>();
        //... arraylist gets filled in
        intent = new Intent(this, DatasheetActivity.class);
        bundle = new Bundle();
        bundle.putParcelableArrayList("FlightDataList", (ArrayList<? extends Parcelable>) flightDataList);
        intent.putExtra("Bundle", bundle);

        Log.d("ErrorCustom",Integer.toString(flightDataList.size()));
//Log.d("ErrorCustom",Integer.toString(intent.getExtras().getParcelableArrayList("FlightDataList").size())); //throws null error

        startActivity(intent);

I do want to send the ArrayList, because it gets filled in the current activity (with a progressbar).

score 1 · Answer 1 · answered Oct 08 '19 at 09:24

What you're doing wrong is that you're putting the ParcelableArrayList inside a bundle, put the bundle inside the intent extras (that is a bundle on its own) and then trying to access the ParcelableArrayList straight from the intent extras.

You should put the ParcelableArrayList straight in the Intent's extras like this:

intent.putParcelableArrayListExtra("FlightDataList", (ArrayList<? extends Parcelable>) flightDataList)

And access it through:

intent.getExtras().getParcelableArrayList("FlightDataList")

or

intent.getParcelableArrayListExtra("FlightDataList")

If you want to keep the "double bundle" solution, even tough i won't suggest it, you should access the data in this way:

intent.getExtras().getBundleExtra("Bundle").getParcelableArrayList("FlightDataList")

For more info about passing data between Activities check this

score 1 · Accepted Answer · answered Oct 08 '19 at 09:26

1

Just use putParcelableArrayListExtra with your intent and don't use Bundle.

Try this

Intent intent = new Intent(this, DatasheetActivity.class);
intent.putParcelableArrayListExtra("FlightDataList", flightDataList );
startActivity(intent);

In other activity

Intent intent = getIntent();
    if (intent != null) {
        List<FlightData> flightDataList;
        flightDataList = intent.getParcelableArrayListExtra("FlightDataList");
}

answered Oct 08 '19 at 09:26

Vince VD

1,506
17
38

This finally works. I used Bundle becuase it wouldn't work with only intent in my other posted question: https://stackoverflow.com/questions/58257776/how-do-i-iterate-through-an-arraylist-of-custom-objects-from-intent-and-add-them – Oct 08 '19 at 09:36

How to send ArrayList() through activities

2 Answers2