packages/flutter/lib/src/material/text_form_field.dart

// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'package:flutter/services.dart';
import 'package:flutter/widgets.dart';

import 'input_decorator.dart';
import 'text_field.dart';

/// A [FormField] that contains a [TextField].
///
/// This is a convenience widget that simply wraps a [TextField] widget in a
/// [FormField].
///
/// A [Form] ancestor is not required. The [Form] simply makes it easier to
/// save, reset, or validate multiple fields at once. To use without a [Form],
/// pass a [GlobalKey] to the constructor and use [GlobalKey.currentState] to
/// save or reset the form field.
///
/// For a documentation about the various parameters, see [TextField].
///
/// See also:
///
///  * <https://material.google.com/components/text-fields.html>
///  * [TextField], which is the underlying text field without the [Form]
///    integration.
///  * [InputDecorator], which shows the labels and other visual elements that
///    surround the actual text editing widget.
class TextFormField extends FormField<String> {
  /// Creates a [FormField] that contains a [TextField].
  ///
  /// For documentation about the various parameters, see the [TextField] class
  /// and [new TextField], the constructor.
  TextFormField({
    Key key,
    TextEditingController controller,
    FocusNode focusNode,
    InputDecoration decoration: const InputDecoration(),
    TextInputType keyboardType: TextInputType.text,
    TextStyle style,
    bool autofocus: false,
    bool obscureText: false,
    bool autocorrect: true,
    int maxLines: 1,
    FormFieldSetter<String> onSaved,
    FormFieldValidator<String> validator,
    List<TextInputFormatter> inputFormatters,
  }) : assert(keyboardType != null),
       assert(autofocus != null),
       assert(obscureText != null),
       assert(autocorrect != null),
       assert(maxLines == null || maxLines > 0),
       super(
    key: key,
    initialValue: controller != null ? controller.value.text : '',
    onSaved: onSaved,
    validator: validator,
    builder: (FormFieldState<String> field) {
      return new TextField(
        controller: controller,
        focusNode: focusNode,
        decoration: decoration.copyWith(errorText: field.errorText),
        keyboardType: keyboardType,
        style: style,
        autofocus: autofocus,
        obscureText: obscureText,
        autocorrect: autocorrect,
        maxLines: maxLines,
        onChanged: field.onChanged,
        inputFormatters: inputFormatters,
      );
    },
  );
}