Autocomplete Text Input only shows items that matches to the first letter only

Question

I am using Autocomplete Text Input control of xamain. Autocomplete reference

Here is my code

var autoCompleteOptions = GetAllContacts();
ArrayAdapter autoCompleteAdapter = new ArrayAdapter(this, Android.Resource.Layout.SimpleDropDownItem1Line, autoCompleteOptions);
speedSearch = FindViewById<AutoCompleteTextView>(Resource.Id.AutoCompleteInput);
speedSearch.Adapter = autoCompleteAdapter;

Problem is when i try to search in my contacts, i only get the suggested values that matches the first letter only. for example if [paul@email.com, tom@email.com,bill@xamarin.com] is the list of contacts, if i make search with "xamarin" Autocomplete does not returns anything, but if i search with "bill" it will return. How can i change an autocompelte's behavior so that any part of string in an array item is searched, it should be returned.

Answer 1

You need create a custom adapter and implement IFilterable.

Here is the source code of ArrayAdapter( java codes), you can find these codes in ArrayFilter.performFiltering():

if (valueText.startsWith(prefixString)) {
    newValues.add(value);
} else {
    final String[] words = valueText.split(" ");
    for (String word : words) {
        if (word.startsWith(prefixString)) {
            newValues.add(value);
            break;
        }
    }
}

Note startsWith, that is why you can't get "bill@xamarin.com" while you input "xa". You need change it to Contains.

---

Here is a fast way to achieve your goal.

Here is a class--AutoAdapter (C# codes) which has already implemented ArrayAdapter and IFilterable.

You just need copy and paste it, and then replace:

            var matches = from i in a.AllItems
                        where i.IndexOf(searchFor) >= 0
                        select i;

with:

            var matches = from i in a.AllItems
                          where i.Contains(searchFor)
                          select i;

And at last, use AutoAdapter in your MainActivity:

    AutoCompleteTextView textView = FindViewById<AutoCompleteTextView>(Resource.Id.autocomplete_country);
    var adapter = new AutoAdapter(this, Resource.Layout.list_item, COUNTRIES);
    textView.Threshold=1;
    textView.Adapter = adapter;

Note:

You also need to look at performFiltering and publishResults methods in Filter class