Set a drawable as background programmatically

EDIT: Sorry I realise from your comment my question was not clear enough. I will post a new one. Sorry for this and thanks for your answers

I am populating a ListView from a Json file.

With my listadapter, I can easily assign appropriate json data to each row of my list. That works well for text, for example:

TextView tv = (TextView)ll.findViewById(R.id.descView);   
tv.setText(i.desc);

With the above code, every row will be correctly populated by the good json data.

However, I don't manage to do the same thing for an image. I have tried to set the right image from my json data using this:

ImageView iv = (ImageView)ll.findViewById(R.id.imgView);           
iv.setBackgroundDrawable(context.getResources().getDrawable(i.img));

I guess I am doing something wrong with the type of my parameters: "setBackgroundDrawable" requires a drawable parameter. "getDrawable" requires an int. I have set the type of my field img to int, but that doesn't work.

Any idea why?

My list adapter:

public class adapter extends ArrayAdapter<ListItems> {

int resource;
String response;
Context context;

//Initialize adapter
public ListItemsAdapter(Context context, int resource, List<ListItems> items) {
    super(context, resource, items);
    this.resource=resource; 
}     

@Override
public View getView(int position, View convertView, ViewGroup parent)
{

    //Get the current object
    ListItems i = getItem(position);

    //Inflate the view
    if(convertView==null)
    {
        ll = new LinearLayout(getContext());
        String inflater = Context.LAYOUT_INFLATER_SERVICE;
        LayoutInflater li;
        li = (LayoutInflater)getContext().getSystemService(inflater);
        li.inflate(resource, ll, true);
    }
    else
    {
        ll = (LinearLayout) convertView;
    }

    //For the message
    Tex