Text form field initial value (#15484)
diff --git a/packages/flutter/lib/src/material/text_form_field.dart b/packages/flutter/lib/src/material/text_form_field.dart
index 38f5690..fea3d66 100644
--- a/packages/flutter/lib/src/material/text_form_field.dart
+++ b/packages/flutter/lib/src/material/text_form_field.dart
@@ -19,9 +19,15 @@
/// pass a [GlobalKey] to the constructor and use [GlobalKey.currentState] to
/// save or reset the form field.
///
-/// When a [controller] is specified, it can be used to control the text being
-/// edited. Its content will be overwritten by [initialValue] (which defaults
-/// to the empty string) on creation and when [reset] is called.
+/// When a [controller] is specified, its [TextEditingController.text]
+/// defines the [initialValue]. If this [FormField] is part of a scrolling
+/// container that lazily constructs its children, like a [ListView] or a
+/// [CustomScrollView], then a [controller] should be specified.
+/// The controller's lifetime should be managed by a stateful widget ancestor
+/// of the scrolling container.
+///
+/// If a [controller] is not specified, [initialValue] can be used to give
+/// the automatically generated controller an initial value.
///
/// For a documentation about the various parameters, see [TextField].
///
@@ -35,16 +41,17 @@
class TextFormField extends FormField<String> {
/// Creates a [FormField] that contains a [TextField].
///
- /// When a [controller] is specified, it can be used to control the text
- /// being edited. Its content will be overwritten by [initialValue] (which
- /// defaults to the empty string) on creation and when [reset] is called.
+ /// When a [controller] is specified, [initialValue] must be null (the
+ /// default). If [controller] is null, then a [TextEditingController]
+ /// will be constructed automatically and its `text` will be initialized
+ /// to [initalValue] or the empty string.
///
/// For documentation about the various parameters, see the [TextField] class
/// and [new TextField], the constructor.
TextFormField({
Key key,
this.controller,
- String initialValue: '',
+ String initialValue,
FocusNode focusNode,
InputDecoration decoration: const InputDecoration(),
TextInputType keyboardType: TextInputType.text,
@@ -58,7 +65,7 @@
FormFieldSetter<String> onSaved,
FormFieldValidator<String> validator,
List<TextInputFormatter> inputFormatters,
- }) : assert(initialValue != null),
+ }) : assert(initialValue == null || controller == null),
assert(keyboardType != null),
assert(textAlign != null),
assert(autofocus != null),
@@ -67,7 +74,7 @@
assert(maxLines == null || maxLines > 0),
super(
key: key,
- initialValue: initialValue,
+ initialValue: controller != null ? controller.text : (initialValue ?? ''),
onSaved: onSaved,
validator: validator,
builder: (FormFieldState<String> field) {
@@ -94,7 +101,8 @@
/// Controls the text being edited.
///
- /// If null, this widget will create its own [TextEditingController].
+ /// If null, this widget will create its own [TextEditingController] and
+ /// initialize its [TextEditingController.text] with [initialValue].
final TextEditingController controller;
@override
@@ -115,7 +123,6 @@
if (widget.controller == null) {
_controller = new TextEditingController(text: widget.initialValue);
} else {
- widget.controller.text = widget.initialValue;
widget.controller.addListener(_handleControllerChanged);
}
}
diff --git a/packages/flutter/test/widgets/form_test.dart b/packages/flutter/test/widgets/form_test.dart
index 44e81af..4756b5c 100644
--- a/packages/flutter/test/widgets/form_test.dart
+++ b/packages/flutter/test/widgets/form_test.dart
@@ -204,8 +204,8 @@
expect(editableText.widget.controller.text, equals('world'));
});
- testWidgets('Provide initial value to input when controller is specified', (WidgetTester tester) async {
- final TextEditingController controller = new TextEditingController();
+ testWidgets('Controller defines initial value', (WidgetTester tester) async {
+ final TextEditingController controller = new TextEditingController(text: 'hello');
const String initialValue = 'hello';
final GlobalKey<FormFieldState<String>> inputKey = new GlobalKey<FormFieldState<String>>();
@@ -217,7 +217,6 @@
child: new Form(
child: new TextFormField(
key: inputKey,
- initialValue: 'hello',
controller: controller,
),
),
@@ -251,7 +250,6 @@
final GlobalKey<FormState> formKey = new GlobalKey<FormState>();
final GlobalKey<FormFieldState<String>> inputKey = new GlobalKey<FormFieldState<String>>();
final TextEditingController controller = new TextEditingController(text: 'Plover');
- const String initialValue = 'Plugh';
Widget builder() {
return new Directionality(
@@ -263,7 +261,7 @@
child: new TextFormField(
key: inputKey,
controller: controller,
- initialValue: initialValue,
+ // initialValue is 'Plover'
),
),
),
@@ -284,9 +282,9 @@
// verify value resets to initialValue on reset.
formKey.currentState.reset();
await tester.idle();
- expect(inputKey.currentState.value, equals(initialValue));
- expect(editableText.widget.controller.text, equals(initialValue));
- expect(controller.text, equals(initialValue));
+ expect(inputKey.currentState.value, equals('Plover'));
+ expect(editableText.widget.controller.text, equals('Plover'));
+ expect(controller.text, equals('Plover'));
});
testWidgets('TextEditingController updates to/from form field value', (WidgetTester tester) async {
