Question

I have an Arraylist of HashMap. Each HashMap element contains two columns: column name and corresponding value. This HashMap will be added into a ListView with 3 TextView.

I populate the ArrayList as follows, and then assign that to an adapter in order to display it:

ArrayList<HashMap<String, String>> list1 = new ArrayList<HashMap<String, String>>();
HashMap<String, String> addList1;
for (int i = 0; i < count; i++) {

addList1 = new HashMap<String, String>();
addList1.put(COLUMN1, symbol[i]);
addList1.put(COLUMN2, current[i]);
addList1.put(COLUMN3, change[i]);

list1.add(addList1);

RecentAdapter adapter1 = new RecentAdapter(CompanyView.this,
                    CompanyView.this, list1);
listrecent.setAdapter(adapter1);
        }

.

Now on listItemClick, the fetched data is of the different form at different time.

For eg. My list contains following data:

ABC  123  1
PQR  456  4
XYZ  789  7

i.e. When I log the fetched string after clicking 1st list item, I get one of the several outputs:

{1=ABC ,2=123 ,3=1}

{First=ABC ,Second=123 ,Third=1}

{1=123 ,0=ABC ,2=1}

and even
{27=123 ,28=1 ,26=ABC}

Initially I used:

int pos1 = item.indexOf("1=");
int pos2 = item.indexOf("2=");
int pos3 = item.indexOf("3=");

String symbol = item.substring(pos1 + 2,pos1 - 2).trim();
String current = item.substring(pos2 + 2, pos3 - 2).trim();
String change = item.substring(pos3 + 2, item.length() - 1).trim();

Then for the 4th case, I have to use:

int pos1 = item.indexOf("26=");
int pos2 = item.indexOf("27=");
int pos3 = item.indexOf("28=");

String symbol = item.substring(pos1 + 3, item.length() - 1).trim();
String current = item.substring(pos2 + 3, pos3 - 3).trim();
String change = item.substring(pos3 + 3, pos1 - 3).trim();

So that I get ABC in symbol and so on.

But, by this approach, application loses it’s reliability completely.

I also tried

while (myVeryOwnIterator.hasNext()) {

key = (String) myVeryOwnIterator.next();
value[ind] = (String) addList1.get(key);
                }

But it’s not giving proper value. Instead it returns random symbol for eg. ABC or PQR or XYZ.

Am I doing anything wrong?

Thanks in advance!

Answer 1

The HashMap’s put function does not insert value in specific order. So the best way is to put the keyset of the HashMap in a ArrayList and use the ArrayList index in retrieving the value

ArrayList<HashMap<String, String>> list1 = new ArrayList<HashMap<String, String>>();
HashMap<String, String> addList1;
ArrayList<String> listKeySet;
for (int i = 0; i < count; i++) {

addList1 = new HashMap<String, String>();
addList1.put(COLUMN1, symbol[i]);
addList1.put(COLUMN2, current[i]);
addList1.put(COLUMN3, change[i]);

listKeySet.add(COLUMN1);
listKeySet.add(COLUMN2);
listKeySet.add(COLUMN3);

list1.add(addList1);

RecentAdapter adapter1 = new RecentAdapter(CompanyView.this,
                CompanyView.this, list1);
listrecent.setAdapter(adapter1);
}

And when retrieving use

addList1.get(listKeySet.get(position));

Here, the arraylist listKeySet is just used to preserve the order in which the HashMap keys are inserted. When you put data in HashMap insert the key into the ArrayList.