我发现了这个multiple_select包，里面有一个搜索器。希望对社区有所帮助。

你可以使用flutter_typeahead

TypeAheadField(
  textFieldConfiguration: TextFieldConfiguration(
    decoration: InputDecoration(labelText: 'Select Items'),
  ),
  suggestionsCallback: (pattern) {
    // Implement a function to provide suggestions based on the search pattern.
    // You can fetch suggestions from your data source (e.g., a list or API).
    // Return a list of suggestions that match the pattern.
  },
  itemBuilder: (context, suggestion) {
    // Build the suggestion item UI based on the suggestion.
    return ListTile(
      title: Text(suggestion),
    );
  },
  onSuggestionSelected: (suggestion) {
    // Handle the selection of a suggestion.
    // Add the selected value to your list of selected items.
  },
  keepSuggestionsOnLoading: false,
),

您可以使用autocomplete_textfield package
source to how to actually implement one。