Question

I have an ArrayList which contains duplicate values at diff diff index.
for example {"Indian","American","Chinese","Australian","Indian","Russian","Indian"}
as u can see the value – "Indian" exists at index – 0, 4 & 6.

I need to know all these indexes where "Indian" exists and create an arrayList of that.
Here is my code:

public void filter(){


    categoryArray = Arrays.asList(category);

    for(String k : category){
        //Log.v("filter", filterTerm);
        if(k.equals(filterTerm.toLowerCase()))
        {               
            int p = categoryArray.indexOf(k);                   
            Log.v("index of categArr", ""+p);
            String id = Integer.toString(p);
            indexes.add(id);


        }// end of if
    }// end of for

Here I get how many times duplicate occurs by getting the size of indexes(ArrayList)
but when I check the values . Its one value at all index since in the method : indexOf() it always brings the index of first value that it finds in the Array.

So if duplicate exists at index – 2,5,7
I get the array size of index as 3.
But the values are {2,2,2,};

Answer 1

You need to know which index in the array you are currently at, not the first index where it is to be found. To keep track of that, put

int i = 0;

before the loop, and at the very end of the loop put

i++;

Then the variable i tells you where you have found the value, so you can add i to the indexes list.