I have a spinner in UI, which I want to hide when I handle onClick method for a button. But the application is crashing all the time. Is it that I can't use the setVisibility(View.Gone) on spinners (it is not written anywhere). If I comment it out, then application run fine. I am getting NullPointerException and I am using RelativeLayout. Also, can I do this:

public void onItemSelected(AdapterView<?> arg0, View view, int pos,
            long arg3) {
        // TODO Auto-generated method stub

                        Toast.makeText(SpinnerActivity.this,selected , Toast.LENGTH_SHORT).show();
            spinner.setVisibility(View.GONE);
        }
    }

Spinner code fore reference:

itemsCity=getResources().getStringArray(R.array.cities_array);

    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
            this, R.array.cities_array, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinnerCity.setAdapter(adapter);

And here is Button code:

private class BtClickListner implements View.OnClickListener{

    @Override
    public void onClick(View v) {

        essEditText.setVisibility(View.GONE);
        spinnerCity.setEnabled(false);// Getting exception here
                     // Also tried
                    spinnerCity.setVisibility(View.GONE);// Exception 
                    SameBt.setVisibility(View.GONE);// This is same button for which I am handliing event, but it allows me to change tis property at run time.

    }