Passing ArrayList through Intents

Question

I have a problem with passing an ArrayList to another activity in Android Studio.

I created a ArrayList that holds the data type Double. The program should read it and print it in the console.

This is the code from the first activity:

 Intent intent = new Intent(this, ergebnisse.class);
 intent.putExtra("WLTP_list", Wlist);
 startActivity(intent);

And this is the code from the second activity:

Bundle bundle = getIntent().getExtras();
ArrayList<Double> Wlist = (ArrayList<Double>) bundle.getDoubleArray("WLTP_list");

The part after the last equal sign is marked red and the error is:

Inconvertible types; cannot cast 'double[]' to 'Java.util.ArrayList<Java.lang.Double>'

I didn't change the type so I don't know why it is giving me that error.

Please show a [mcve]. What does `bundle.getDoubleArray` returns? Or, what `Wlist` is in the first snippet? — user202729, Jul 30 '18 at 15:46
Is because `getDoubleArray` return `double[]` not `ArrayList`.See this doc https://developer.android.com/reference/android/os/BaseBundle — Crammeur, Jul 30 '18 at 15:47
Possible duplicate of [Pass ArrayList from one activity to another activity on android](https://stackoverflow.com/questions/11648312/pass-arraylistdouble-from-one-activity-to-another-activity-on-android) — Belbahar Raouf, Jul 30 '18 at 15:54

score 1 · Answer 1 · answered Jul 30 '18 at 15:47

1

You are calling bundle.getDoubleArray(), which returns an array, instead of an ArrayList, that's why you're getting the error as you're trying to convert an double[] array into an ArrayList.

answered Jul 30 '18 at 15:47

Dom

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score 1 · Answer 2 · answered Jul 30 '18 at 15:55

The getDoubleArray() method returns an array of type double[], which cannot be explicitly cast to ArrayList. If you really want to use it as an ArrayList, you need to get that double[] array and explicitly convert it to an ArrayList. For instance, something like

 ArrayList<Double> Wlist = ArrayList<Double>(Arrays.asList( bundle.getDoubleArray("WLTP_list")));

score 1 · Answer 3 · answered Jul 30 '18 at 16:29

Trying this way.

First Activity:

 Intent intent = new Intent(this, SecondActivity.class);
    ArrayList<Double> listDouble = new ArrayList<Double>();
    listDouble.add(1.0);
    listDouble.add(2.0);
    intent.putExtra("WLTP_list", listDouble);
    startActivity(intent);

Second Activity:

    ArrayList<Double> listDouble = (ArrayList<Double>) getIntent().getSerializableExtra("WLTP_list");
System.out.println("Return.." + listDouble);

Jacob · Answer 4 · 2018-07-30T15:54:12.933

0

Try this code in your second activity instead:

ArrayList<Double> Wlist = (ArrayList<Double>) getIntent().getSerializableExtra("WLTP_list");

The current method you are using returns an Array of the data type Double, not an ArrayList. The code I provided should give you an ArrayList instead.

If that line doesn't work, you can always look at this answer.

edited Jul 30 '18 at 15:54

answered Jul 30 '18 at 15:50

Jacob

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Passing ArrayList through Intents

4 Answers4