Update elements in an ArrayList by its index in Cloud Firestore

Asked Jun 07 '19 at 11:40

Active Jun 07 '19 at 11:44

Viewed 118 times

I am storing an ArrayList in Cloud Firestore where the index is the month and the value is a value! like so :

mList.add(0, 10);  //where 0 is January and 10 is its correspondent value  
mList.add(1, 144);
mList.add(2, 23);
//...
mList.add(11, 332);

I want to update let's say february, what I normally would do is:

mList.set(1, 100); 
//since the index starts at 0, 
//February would be at index 1 and the value gets changed from 144 to 100

This is my model class:

public class History {
    private ArrayList<Integer> valuesList = new ArrayList<>(12);

    public History() {}

    public History(ArrayList<Integer> valuesList) {
        this.valuesList = valuesList;
    }

    public ArrayList<Integer> getValuesList() {
        return valuesList;
    }

    public void setValuesList(ArrayList<Integer> valuesList) {
        this.valuesList = valuesList;
    }
}

I know that need to use .update(data) but I do not exactly how to update a specific value by the index, so the question is how to it ?

edited Jun 07 '19 at 11:44

Doug Stevenson

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asked Jun 07 '19 at 11:40

Thorvald

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The arraylist is stored in Firestore document in an array right? – Vedprakash Wagh Jun 07 '19 at 11:45
@VedprakashWagh indeed, yes – Thorvald Jun 07 '19 at 11:46
Then you cannot update the specific index in Firestore – Vedprakash Wagh Jun 07 '19 at 11:47
Please show us how your database structure looks like. – Alex Mamo Jun 07 '19 at 11:47
1

There is no way to directly update a list type field in Cloud Firestore. You have to read the document, modify it in memory, then update the document with the new data. Perhaps you want to use an object instead of a list. – Doug Stevenson Jun 07 '19 at 11:47

Update elements in an ArrayList by its index in Cloud Firestore

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