how to copy one arrayList to another without refrencing first?

Question

I tried all way but always it is referencing the previous one.

mListPreviousData = new ArrayList<>();
for (int i = 0; i < mAddedList.size(); i++) {
    mListPreviousData.add(mAddedList.get(i));
}

just do mListPreviousData = (ArrayList) mAddedList.clone(); You need to cast in to your arraylist type — Divyang Panchal, Feb 03 '17 at 09:53
type of both arrayList is same that's why it is referencing the previous one — UserSharma, Feb 03 '17 at 09:55
You can use [this](https://github.com/google/guava) library or by constructor you can get **shallow** copy. — DwlRathod, Feb 03 '17 at 09:55
Possible duplicate of [How do I copy the contents of one ArrayList into another?](http://stackoverflow.com/questions/8441664/how-do-i-copy-the-contents-of-one-arraylist-into-another) — Ankush Bist, Feb 03 '17 at 10:01
If you do not want to create two separate list by cloning your list object , Then you need to create Data List Item Each time within loop and then add into your mListPreviousData list .Meas you need to create new object each time. — Chetan Joshi, Feb 03 '17 at 10:54

score 2 · Answer 1 · answered Feb 03 '17 at 09:54

2

You need to make a deep copy of the underlying objects:

mListPreviousData = new ArrayList<>();
for (int i = 0; i < mAddedList.size(); i++) {
    mListPreviousData.add(mAddedList.get(i).clone());
}

Preferably, you implement your own clone() method.

Edit:

Or do a deep copy of the entire arraylist:

mListPreviousData = (..cast to your type..) mAddedList.clone();

answered Feb 03 '17 at 09:54

Tobias G

drawback if the original list data is changed the cloned copy will automatically updated – Ankush Bist Feb 03 '17 at 09:59
same thing i don't want i need two separate lists. – UserSharma Feb 03 '17 at 10:02
If you do not want to create two separate list by cloning your list object , Then you need to create Data List Item Each time within loop and then add into your mListPreviousData list .Meas you need to create new object each time – Chetan Joshi Feb 03 '17 at 10:55

score 1 · Accepted Answer · answered Feb 03 '17 at 10:15

1

mListPreviousData = new ArrayList<>(); 
mListPreviousData.addAll(mAddedList);

answered Feb 03 '17 at 10:15

Bishu

Please provide a specific body to your answer, for better understanding. – W4R10CK Feb 03 '17 at 10:33

2 Answers2