CODEWITHSUNDEEP
javaandroidstringarraylist
user2076033
user2076033

Reputation: 5

For Loop doesnt add point to an array

I have the following for loop which looks through a string ArrayList of results, each item in the string is seperated by "::":

ArrayList<String> resultsArray = MyClass.results;
        Integer numPoints = resultsArray.size();

        for (int i =0;i<numPoints;i++){
            String[] pointDetails = resultsArray.get(i).split("::");
            String pointName = pointDetails[0];
            String pointDescription = pointDetails[1];
            String coordinates = pointDetails[2];

        //Turn coordinates into geopoints
            String coord[] = coords.split(",");
            Integer  lng= (int) (Double.valueOf(coord[0]) * 1000000);
            Integer lat = (int)(Double.valueOf(coord[1])*1000000);
            GeoPoint gPoint = new GeoPoint(lng,lat);


         arrayPointName = new ArrayList <String>();
         arrayPointDescription = new ArrayList <String>();
         arrayPointCoords=new ArrayList<GeoPoint>();
         arrayPointName.add(pointName);
         arrayPointDescription.add(pointDescription);
     arrayPointCoords.add(gPoint);
          }

I know I have 20 points in the initial string ArrayList and have printed out its size to check this. However, when I print out the new arraylists, such as arrayPointName, they only contain one point. Any idea on why this is?

Upvotes: 0

Views: 343

Answers (2)

Aydroid
Aydroid

Reputation: 81

you used coords as an ArrayList Without initiate it .Also you initiate for each iteration arrayPointName, arrayPointDescription and arrayPointCoords that's why they lost the value created in the previous iteration. they should be initiate juste one time before starting the loop

it will be easy to help you if you give us a sample of resultsArray strring.

Upvotes: 0

Jon Skeet
Jon Skeet

Reputation: 1500665

Look at this code:

arrayPointName = new ArrayList <String>();
arrayPointDescription = new ArrayList <String>();
arrayPointCoords=new ArrayList<GeoPoint>();

Those three statements - assigning new, empty ArrayList references to your variables - are being executed on every iteration of your loop.

They should come before your loop instead: you only want to initialize the variables once (creating the three lists) and then add a new item on each iteration.

As a side note, populating multiple collections like this is normally a bad idea. It's usually better to create a single type which encapsulates the related data (name, description, coordinates in this case) and then create a single collection of items of that type. That's usually a lot easier to work with.

Upvotes: 7

Related Questions