How to set my first value (default value) in spinn

Question

How to set my first value (default value) in spinner as empty. Means, until the user selects value from list, spinner will have no value. I tried below

list.add(""); 

But, it won't work. Below is my code :

if(values.contains("options")){
       spinner.setOnItemSelectedListener(MyClass.this);
       List<String> list = new ArrayList<String>();
       list.add("");
       list.add("Test");
       list.add("Working");
       ArrayAdapter<String> adapter = new ArrayAdapter<String>(mContext, android.R.layout.simple_spinner_item, list) {};

      adapter.setDropDownViewResource(R.layout.custom_spinner_list);
      spinner.setAdapter(adapter);     
   }
 }

Answer 1

i found out the way. Here is how we do it, let the last line be

list.add("");

and add below code :

ArrayAdapter<String> adapter = new ArrayAdapter<String>(mContext, android.R.layout.simple_spinner_item, list) {

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

                                View v = super.getView(position, convertView, parent);
                                if (position == getCount()) {
                                    ((TextView)v.findViewById(android.R.id.text1)).setText("");
                                    ((TextView)v.findViewById(android.R.id.text1)).setHint(getItem(getCount())); //"Hint to be displayed"
                                }

                                return v;
                            }       

                            @Override
                            public int getCount() {
                                return super.getCount()-1;            // you don't display last item. It is used as hint.
                            }

                    };


                    adapter.setDropDownViewResource(R.layout.custom_spinner_list);
                    spinner.setAdapter(adapter);
                    spinner.setSelection(adapter.getCount());        //set the hint the default selection so it appears on launch.
                    spinner.setOnItemSelectedListener(this);
                    notifyDataSetChanged();        

Answer 2

Thanks to user45678's answer above, I wrote this

public class SpinnerNoDefault extends Spinner {

public void initialize(List<String> items) {
    initialize(items, android.R.layout.simple_spinner_item, android.R.layout.simple_spinner_dropdown_item);
}

public void initialize(List<String> items, @LayoutRes int mItemResId, @LayoutRes int dropdownResId) {
    List<String> itemsWithEmpty = new ArrayList<>(items);
    itemsWithEmpty.add("");

    String[] choicesArray = itemsWithEmpty.toArray(new String[itemsWithEmpty.size()]);
    ArrayAdapter<String> spinnerArrayAdapter = new ArrayAdapter<String>(getContext(), mItemResId, choicesArray) {
        @NonNull
        @Override
        public View getView(int position, View convertView, @NonNull ViewGroup parent) {
            View v = super.getView(position, convertView, parent);
            if (position == getCount()) {
                ((TextView)v.findViewById(android.R.id.text1)).setText(null);
                ((TextView)v.findViewById(android.R.id.text1)).setHint(parent.getContext().getString(R.string.spinner_no_default_hint));
            }

            return v;
        }

        @Override
        public int getCount() {
            // Don't display last item. It is used as hint.
            return super.getCount()-1;
        }
    };

    spinnerArrayAdapter.setDropDownViewResource(dropdownResId);
    setAdapter(spinnerArrayAdapter);
    setSelection(itemsWithEmpty.size()-1);
}
}