Question

I am struggling with Android Lists and how to convert them for use in a Spinner. Putting a string array into a Spinner is very simple, therefore, I figured doing the same with a List would also be simple. At this time however I can not figure out how to get the List into the proper format for use with the Spinner’s ArrayAdapter.

Here’s my code for grabbing a list of account names from the database:

//---retrieves all the accounts matching the account_type---
    public List getAccounts(String account_type) {      
        List<String> list = new ArrayList<String>();
        Cursor cursor = this.db.query(DBACCOUNTS, new String[] {
                ID,
                ACCOUNTTYPE,
                ACCOUNTNUMBER,
                ACCOUNTNAME},
                ACCOUNTTYPE + " = " + "'" + account_type + "'",
                null, 
                null, 
                null, 
                null, 
                null);
        if (cursor.moveToFirst()) {
           do {
              //---account_name column number is 3--- 
              list.add(cursor.getString(3));
           } while (cursor.moveToNext());
        }
        if (cursor != null && !cursor.isClosed()) {
           cursor.close();
        }

        return list;
    }

From the returned “list”, what do I need to do to populate my spinner? The following code is obviously for a string array, however, I am lost as to what I need to do to make a List work with similar functionality. Here’s my non-working ArrayAdapter code (account_name_array is set to be the returned “list” from above):

account_name_spinner = (Spinner) findViewById(R.id.account_name_spinner);      
account_name_adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, account_name_array);
account_name_adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
account_name_spinner.setAdapter(account_name_adapter);

I know I am way off track here, I know that ArrayAdapter is expecting a string array, however, like I said, I need a good push in the right direction. Obviously I need to either convert my List into a string array, or change the way I am adapting the Spinner to the List. Android has been quite difficult for me to grasp, there are a lot of data structures and much more data type rules than I am use to coming from a PHP background.

You’re help is greatly appreciated!

Answer 1

Use toArray to convert your list into an array.

List<String> list = new ArrayList<String>(); // Your list
// Populate it

// Then get an array:
String[] array = list.toArray( new String[0] );