Minimum chars before sending request?

[wiradikusuma]

How do I set minimum chars before suggestionsCallback is triggered?

[sjmcdowall]

You can’t .. why not just get check the pattern length in the callback before and return an empty of previous result if not long enough?!

…

Sent from my iPad

On Apr 6, 2019, at 3:14 AM, Thomas Wiradikusuma ***@***.***> wrote: How do I set minimum chars before suggestionsCallback is triggered? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or mute the thread.

[wiradikusuma]

That's actually a good idea. Thanks!

[claudelk]

@sjmcdowall can we reopen this one? Checking the pattern length fires an exception, even if the pattern is not empty (and not null):

Code:

TypeAheadField(
            textFieldConfiguration: TextFieldConfiguration(
                focusNode: _recipientsFocusNode,
                autofocus: true,
                /*style: DefaultTextStyle.of(context)
                .style
                 .copyWith(fontStyle: FontStyle.italic) */
                decoration: InputDecoration(labelText: sField)
                /* decoration: InputDecoration(border: OutlineInputBorder()) */
                ),
            suggestionsCallback: (value) async {
              if (value != null && value != '') {
                if (value.startsWith('@') && value.length >= 2)
                  await model.getNamesBySuggestion(value);
              } else
                return null;
            },
            itemBuilder: (context, suggestion) {
              return SingleChildScrollView(
                child: ListTile(
                  leading: Icon(Icons.portrait), // to change
                  title: Text(suggestion), //to change
                  //subtitle: Text('\$${suggestion['price']}'), // to change
                ),
              );
            },
            onSuggestionSelected: (suggestion) {
              //set the full name as part of the field, add a coma and allow the user to select another recipient
              //Navigator.of(context).push(MaterialPageRoute(builder: (context) => {}));
            },
          )

Result:

[VERBOSE-2:ui_dart_state.cc(148)] Unhandled Exception: NoSuchMethodError: The getter 'length' was called on null.
Receiver: null
Tried calling: length
#0      Object.noSuchMethod (dart:core/runtime/libobject_patch.dart:50:5)
#1      _SuggestionsListState._getSuggestions.<anonymous closure> (package:flutter_typeahead/flutter_typeahead.dart:1032:44)
#2      State.setState (package:flutter/src/widgets/framework.dart:1122:30)
#3      _SuggestionsListState._getSuggestions (package:flutter_typeahead/flutter_typeahead.dart:1030:9)
<asynchronous suspension>
#4      _SuggestionsListState.initState.<anonymous closure>.<anonymous closure> (package:flutter_typeahead/flutter_typeahead.dart:993:20)
<asynchronous suspension>
#5      _rootRun (dart:async/zone.dart:1120:38)
#6      _CustomZone.run (dart:async/zone.dart:1021:19)
#7      _CustomZone.runGuarded (dart:async/zone.dart:923:7)
#8      _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:963:23)
#9      _rootRun (dart:async/zone.dart:112<…>

[claudelk]

Fixed it with this:

suggestionsCallback: (value) async {
              if (value != null && value != '') {
                if (value.startsWith('@') && value.length >= 3)
                  return await model.getNamesBySuggestion(value);
                else
                  return [];
              } else
                return [];
            },

Always making sure to return an empty list if no call.

[KaYBlitZ]

That's pretty interesting. I am going to make a fix that will allow returning null. If you return an empty list, then it will show the no items! box. If you return null, a suggestions box will not show at all.

[qbait]

@KaYBlitZ have you implemented it at the end?

[MOhsain]

@qbait @KaYBlitZ @claudelk @alphamikle I was using this version flutter_typeahead: ^1.7.0. This version was working fine but now i ugrade this to 3.1.1. now it is not showing any list.
if i pass empty list then it show not item found error. kindly help me
And here is my Code ->
suggestionsCallback: (value) async {
if (value != null && value != '') {
if (value.length >= 1)
return await UserData.getSuggestions(value);
else
return null;
} else
return null;
},

[sjmcdowall]

I think it's the null protection added in 3.x. You shouldn't really return a null but instead an empty set of whatever type UserData.getSuggestions(value) would return .. just make it an empty array or whatever of that type?

[MOhsain]

UserData.getSuggestions its a just String Array.
When i pass empty list " return [[ " instead of " return null ", its showing no item found error....
So kindly guide me. Have you tried this like suggestions will be shown after 2 charectors with 3.x?