public class DownloadPicker extends PreferenceActivity {
    DatabaseHelper locationData;

    @Override
    public void onCreate(Bundle savedInstanceState) {
    	super.onCreate(savedInstanceState);

    	PreferenceScreen root = getPreferenceManager().createPreferenceScreen(this);
    	root.setTitle("Choose clock packs");

    	locationData = new DatabaseHelper(this);
		SQLiteDatabase db = locationData.getReadableDatabase();

		String[] cColumns = {"country"};
		String[] cParms = {"1"};

		Cursor countrys = db.query("location", cColumns, "complete=?", cParms, "country", null, "country");
    	countrys.moveToFirst();

		while(!countrys.isAfterLast()) {
			PreferenceScreen ps = getPreferenceManager().createPreferenceScreen(this);
			ps.setTitle(countrys.getString(0));

			root.addPreference(ps);

			String[] dColumns = {"place", "_id", "downloaded"};
			String[] dParms = {countrys.getString(0), "1"};

			Cursor cities = db.query("location", dColumns, "country=? AND complete=?", dParms, null, null, "place");
			cities.moveToFirst();

			while(!cities.isAfterLast()) {
				CheckBoxPreference cb = new CheckBoxPreference(this);
				cb.setTitle(cities.getString(0));
				cb.setKey(countrys.getString(0) + "-" + cities.getString(0));
		        cb.setPersistent(true);

		        if(cities.getInt(2) == 1)
		        	cb.setChecked(true);
		        else
		        	cb.setChecked(false);

		        final String[] dID = {cities.getString(1)};

		        cb.setOnPreferenceClickListener(new OnPreferenceClickListener() {

		        	@Override
		        	public boolean onPreferenceClick(Preference preference) {
		        		ContentValues values = new ContentValues();

		        		DatabaseHelper data = new DatabaseHelper(DownloadPicker.this);
		        		SQLiteDatabase write = data.getWritableDatabase();

		        		if(((CheckBoxPreference) preference).isChecked()) {
			        		// Code for async clock downloading here
		        			values.put("downloaded", "1");
		        			write.update("location", values, "_id=?", dID);

		        			return true;
		        		}
		        		else {
		        			// Delete local clock files
		        			values.put("downloaded", "0");
		        			write.update("location", values, "_id=?", dID);

		        			return true;
		        		}
		        	}
		        });

				ps.addPreference(cb);
				cities.moveToNext();
			}
			countrys.moveToNext();
		}

        setPreferenceScreen(root);
    }
}