Question

I have a listview (multi choice).
It works perfect. I used a custom adapter for it. There is a text in each row and a checkbox.
Marked items will be shown as a result in a textview.

I want to add a spinner inside listview rows. I get null point exception error.
Thanks in advance.

public class MainActivity extends Activity {

ListView myListView;
Button getResult;
Spinner spinner;

private ArrayList<String> dayOfWeekList = new ArrayList<String>();

private void initDayOfWeekList(){
    dayOfWeekList.add("Sunday");
    dayOfWeekList.add("Monday");
    dayOfWeekList.add("Tuesday");
    dayOfWeekList.add("Wednesday");
    dayOfWeekList.add("Thursday");
    dayOfWeekList.add("Friday");
    dayOfWeekList.add("Saturday");

}

String[] androidBooks = 
    {
    "Hello",
    "Professional",
    "Unlocking"
    };

MyArrayAdapter myArrayAdapter;
ArrayAdapter<String> spinnerAdapter;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    initDayOfWeekList();
    setContentView(R.layout.activity_main);
    spinnerAdapter = new ArrayAdapter<String> (this, 
            android.R.layout.simple_spinner_item, androidBooks);




    myListView = (ListView)findViewById(R.id.list);

    myArrayAdapter = new MyArrayAdapter(
            this,
            R.layout.row,
            android.R.id.text1,
            dayOfWeekList
            );

    myListView.setAdapter(myArrayAdapter);
    myListView.setOnItemClickListener(myOnItemClickListener);

    getResult = (Button)findViewById(R.id.getresult);
    getResult.setOnClickListener(new OnClickListener(){

        @Override
        public void onClick(View v) {
            String result = "";

            /*
            //getCheckedItemPositions
            List<Integer> resultList = myArrayAdapter.getCheckedItemPositions();
            for(int i = 0; i < resultList.size(); i++){
                result += String.valueOf(resultList.get(i)) + " ";
            }
            */

            //getCheckedItems
            List<String> resultList = myArrayAdapter.getCheckedItems();
            for(int i = 0; i < resultList.size(); i++){
                result += String.valueOf(resultList.get(i)) + "\n";
            }

            myArrayAdapter.getCheckedItemPositions().toString();
            Toast.makeText(
                    getApplicationContext(), 
                    result, 
                    Toast.LENGTH_LONG).show();
        }});

}

OnItemClickListener myOnItemClickListener
= new OnItemClickListener(){

    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position,
            long id) {
        myArrayAdapter.toggleChecked(position);

    }};

private class MyArrayAdapter extends ArrayAdapter<String>{

    private HashMap<Integer, Boolean> myChecked = new HashMap<Integer, Boolean>();

    public MyArrayAdapter(Context context, int resource,
            int textViewResourceId, List<String> objects) {
        super(context, resource, textViewResourceId, objects);

        for(int i = 0; i < objects.size(); i++){
            myChecked.put(i, false);
        }
    }

    public void toggleChecked(int position){
        if(myChecked.get(position)){
            myChecked.put(position, false);
        }else{
            myChecked.put(position, true);
        }

        notifyDataSetChanged();
    }

    public List<Integer> getCheckedItemPositions(){
        List<Integer> checkedItemPositions = new ArrayList<Integer>();

        for(int i = 0; i < myChecked.size(); i++){
            if (myChecked.get(i)){
                (checkedItemPositions).add(i);
            }
        }

        return checkedItemPositions;
    }

    public List<String> getCheckedItems(){
        List<String> checkedItems = new ArrayList<String>();

        for(int i = 0; i < myChecked.size(); i++){
            if (myChecked.get(i)){
                (checkedItems).add(dayOfWeekList.get(i));
            }
        }

        return checkedItems;
    }

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

        spinner = (Spinner) row.findViewById(R.id.planets_spinner);
        spinner.setAdapter(spinnerAdapter);

        if(row==null){
            LayoutInflater inflater=getLayoutInflater();
            row=inflater.inflate(R.layout.row, parent, false);  
        }

        CheckedTextView checkedTextView =    (CheckedTextView)row.findViewById(R.id.text1);
        checkedTextView.setText(dayOfWeekList.get(position));

        Boolean checked = myChecked.get(position);
        if (checked != null) {
            checkedTextView.setChecked(checked);
        }

        return row;
    }

}

}

Answer 1

You have your code out of order in getView(..)

You are trying to retrieve your spinner before you inflate your view.. If convertView is null (which it will be the first time through your list) your spinner will not be found.. you can’t call findViewById on something that’s null.. Change the order of your operations to the following

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

        if(row==null){
            LayoutInflater inflater=getLayoutInflater();
            row=inflater.inflate(R.layout.row, parent, false);  
        }

        spinner = (Spinner) row.findViewById(R.id.planets_spinner);
        spinner.setAdapter(spinnerAdapter);
        CheckedTextView checkedTextView =    (CheckedTextView)row.findViewById(R.id.text1);
        checkedTextView.setText(dayOfWeekList.get(position));

        Boolean checked = myChecked.get(position);
        if (checked != null) {
            checkedTextView.setChecked(checked);
        }

        return row;
    }

Notice how i moved retrieving the spinner to AFTER checking the view for null and inflating if needed