---
id: autocomplete_triggers
title: Autocomplete Triggers
---

Adding Custom Autocomplete Triggers

### Introduction

The [StreamMessageInput](../../03-stream_chat_flutter/stream_message_input.mdx) widget provides a way to add custom autocomplete triggers using the `StreamMessageInput.customAutocompleteTriggers` property.

By default we provide autocomplete triggers for mentions and commands, but it's very easy to add your custom ones.

### Add Emoji Autocomplete Trigger

To add a custom emoji autocomplete trigger, you must first create an `AutoCompleteOptions` widget.
This widget will be used to show the autocomplete options.

For this example we're using two external dependencies: 

- [emojis](https://pub.dev/packages/emojis)
- [substring_highlight](https://pub.dev/packages/substring_highlight)

```dart
import 'package:emojis/emoji.dart';
import 'package:flutter/material.dart';

import 'package:stream_chat_flutter/stream_chat_flutter.dart';
import 'package:substring_highlight/substring_highlight.dart';

/// Overlay for displaying emoji that can be used
class StreamEmojiAutocompleteOptions extends StatelessWidget {
  /// Constructor for creating a [StreamEmojiAutocompleteOptions]
  const StreamEmojiAutocompleteOptions({
    super.key,
    required this.query,
    this.onEmojiSelected,
  });

  /// Query for searching emoji.
  final String query;

  /// Callback called when an emoji is selected.
  final ValueSetter<Emoji>? onEmojiSelected;

  @override
  Widget build(BuildContext context) {
    final emojis = Emoji.all().where((it) {
      final normalizedQuery = query.toUpperCase();
      final normalizedShortName = it.shortName.toUpperCase();

      return normalizedShortName.contains(normalizedQuery);
    });

    if (emojis.isEmpty) return const SizedBox.shrink();

    return StreamAutocompleteOptions<Emoji>(
      options: emojis,
      optionBuilder: (context, emoji) {
        final themeData = Theme.of(context);
        return ListTile(
          dense: true,
          horizontalTitleGap: 0,
          leading: Text(
            emoji.char,
            style: themeData.textTheme.headline6!.copyWith(
              fontSize: 24,
            ),
          ),
          title: SubstringHighlight(
            text: emoji.shortName,
            term: query,
            textStyleHighlight: themeData.textTheme.headline6!.copyWith(
              color: Colors.yellow,
              fontSize: 14.5,
              fontWeight: FontWeight.bold,
            ),
            textStyle: themeData.textTheme.headline6!.copyWith(
              fontSize: 14.5,
            ),
          ),
          onTap: onEmojiSelected == null ? null : () => onEmojiSelected!(emoji),
        );
      },
    );
  }
}
```

Now it's time to use the `StreamEmojiAutocompleteOptions` widget.

```dart
StreamMessageInput(
  customAutocompleteTriggers: [
    StreamAutocompleteTrigger(
      trigger: ':',
      minimumRequiredCharacters: 2,
      optionsViewBuilder: (
        context,
        autocompleteQuery,
        messageEditingController,
      ) {
        final query = autocompleteQuery.query;
        return StreamEmojiAutocompleteOptions(
          query: query,
          onEmojiSelected: (emoji) {
            // accepting the autocomplete option.
            StreamAutocomplete.of(context).acceptAutocompleteOption(
              emoji.char,
              keepTrigger: false,
            );
          },
        );
      },
    ),
  ],
),
```
