Question

In Android AutoCompleteTextView only show show dropdown when we entered first letter correctly .What I want is when I enter any letter sequence in the string available it should show the drop down.for example “January” is in my array so when i enter “anu” in AutoComplete field it should show “january” in drop down.Please help.
Thank You

Answer 1

You are likely going to have write your own Filter and attach it via a TextWatcher. This response has an example of regex in an AutoCompleteTextView: Android AutoCompleteTextView with Regular Expression? and here is another regex/java example: How can I perform a partial match with java.util.regex.*?

EDIT: You will need to extend ArrayAdapter in order to override getFilter() and return your custom filter.

So you are going to have something like this:

autoCompleteTextView.setAdapter(arrayAdapter);
autoCompleteTextView.addTextChangedListener(new TextWatcher() {
   public void onTextChanged(CharSequence s, int start, int before, int count) {
      arrayAdapter.getFilter().filter(s);
   }
});

public class RegexFilter extends Filter{

   ArrayAdapter<String> mAdapter;
   public RegexFilter(ArrayAdapter<String> adapter) {
      mAdapter = adapter;
   }
...
   @Override
   protected FilterResults performFiltering(CharSequence constraint) {
      Pattern p = Pattern.compile(constraint);
      Matcher m = p.matcher("");
      List listOfMatches = new ArrayList<String>();
      for (String curMonth : months) {
         m.reset(curMonth);
         if (m.matches || m.hitEnd()) {
            listOfMatches.add(curMonth);
         }
      }
      FilterResults results = new FilterResults();
      results.values = listOfMatches;
      results.count = listOfMatches.size();
      return results;
   }

   @Override
   protected void publishResults(CharSequence constraint, FilterResults results) {
      mAdapter.addAll(results.values);
      mAdapter.notifyDataSetChanged();
   }
}

public class PartialArrayAdapter extends ArrayAdapter<String> {
   ...
   RegexFilter mFilter;
   @Override
   public TimedSuggestionFilter getFilter() {
      if(null == mFilter)
         mFilter = new RegexFilter(this);
      return mFilter;
   }