Change Spinner DropDown width

Add Attribute in xml file in Spinner tag

android:dropDownWidth="150dp"

What you need to do is use a custom adapter for the drop-down instead of the default one, where you set the "minimumWidth" of each 'row' to whatever you want:

private class myCustomAdapter extends ArrayAdapter{    private List<String> _navigations;    private int _resource;    private int _textViewResourceId;    public myCustomAdapter (Context context, int resource, int textViewResourceId, List<String> objects) {        super(context, resource, textViewResourceId, objects);        _navigations = objects;        _resource = resrouce;        _textViewResourceId = textViewResourceId;    }    @Override    public View getDropDownView(int position, View convertView, ViewGroup parent){        View row;        LayoutInflater inflater=getLayoutInflater();                    row = inflater.inflate(_resource, null);        TextView _textView = row.findViewById(_textViewResourceId);        _textView.setText(_navigations.get(position));        Display display = getWindowManager().getDefaultDisplay();        Point size = new Point();        display.getSize(size);        int _width = size.x;        row.setMinimumWidth = _width;        return row;    }}

You can of course play with "minimumWidth" to be whatever else you want; In this example it's just set to match the screen width (though a smarter approach would be to measure your app's container frame and match it to that).

Then to set the adapter:

myCustomAdapter adapter = new myCustomAdapter(getBaseContext(), R.layout.custom_spinner_title_bar,android.R.id.text1, navigations);