Question

I have an arraylist called fetchContactName() which returns all names (31) in my contact list, an arraylist called fetchContactNumbers() which returns all phone numbers (31) associated with fetchContactName(), and an arraylist called newList which has all the numbers that sent me text messages (6).

I was trying to change the phone numbers in newList by looking for the same numbers in fetchContactNumbers(). When there was a match, I would then index the position in fetchContactNumbers() and use that index to get the name at the same position in fetchContactName(). From there, I would replace the numbers in newList with the names in fetchContactName() according to the indexed position.

This is an example I’ve made that executes as stated above:

http://pastebin.com/pApHNkXa

The problem with the above example is that when I apply it to my listview, only one element in the list is changed to a name. More oddly, newList.get(3) is the only one that changed to a name. Not newList at positions 0, 1, 2, 4 and 5.

From others suggests, how can I use a HashMap to give the same expected result as the example given above? I was told to use fetchContactNumbers() and fetchContactNames() in the Hashmap then use the HashMap to compare with newList, but I cant find any source to achieve this.

UPDATE:

Here is the working code for my HashMap, but the results are still the same as above:

    for (String str : fetchContactNames()) {
        contactNameNew += str + " ";
    }
    for (String str2 : fetchContactNumbers()) {
        contactNumberNew += str2 + " ";
    }

    //String to split
    String temp[];
    String temp2[];
    String delimiter = " ";

    temp = contactNameNew.split(delimiter);
    temp2 = contactNumberNew.split(delimiter);

    HashMap<String, String> contacts = new HashMap<String, String>();
    contacts.put(contactNameNew, contactNumberNew);
    for(int i = 0; i < fetchContactNames().size(); i++){
        contacts.put(temp[i], temp2[i]);
    }

    Iterator<Entry<String, String>> iterator = contacts.entrySet().iterator();

    while(iterator.hasNext()){

        Entry<String, String> entry = iterator.next();
        int position = getPosition(newlist, entry.getValue());
    if (newlist.contains(entry.getValue())) {

        newlist.set(position, entry.getKey());
        }
    }

Answer 1

I think it will be better if I changed your code and answered…

import java.util.ArrayList;
import java.util.HashMap;

public class StringT {


public static void main(String[] args) {

    // alpha would represent fetchContactNames()
    ArrayList<String> alpha = new ArrayList<String>();
    // bravo would represent fetchContactNumbers()
    HashMap<String, String> bravo = new HashMap<String, String>();
    // charlie would represent newList
    ArrayList<String> charlie = new ArrayList<String>();

    bravo.put("1", "One"); charlie.add("5");
    bravo.put("2", "Two"); charlie.add("1");
    bravo.put("3", "Three"); charlie.add("3");
    bravo.put("4", "Four"); charlie.add("4");
    bravo.put("5", "Five"); charlie.add("2");

    // this will print charlie just as you see above
    for(int i = 0; i < charlie.size(); i ++){
        System.out.println(charlie.get(i));
    }

    System.out.println("---------------------");

    // this will print charlie with the numbers replaced as names
    for(int i = 0; i < charlie.size(); i++){
        String value;
        if((value = bravo.get(charlie.get(i))) != null){
            charlie.set(i, value);
        }
    }

    for(int i = 0; i < charlie.size(); i ++){
        System.out.println(charlie.get(i));
    }
}
}