Updated the gallery text fields demo (#15362)

examples/flutter_gallery/lib/demo/material/text_form_field_demo.dart

@@ -23,6 +23,60 @@ class PersonData {
   String password = '';
 }
 
+class PasswordField extends StatefulWidget {
+  const PasswordField({
+    this.fieldKey,
+    this.hintText,
+    this.labelText,
+    this.helperText,
+    this.onSaved,
+    this.validator,
+    this.onFieldSubmitted,
+  });
+
+  final Key fieldKey;
+  final String hintText;
+  final String labelText;
+  final String helperText;
+  final FormFieldSetter<String> onSaved;
+  final FormFieldValidator<String> validator;
+  final ValueChanged<String> onFieldSubmitted;
+
+  @override
+  _PasswordFieldState createState() => new _PasswordFieldState();
+}
+
+class _PasswordFieldState extends State<PasswordField> {
+  bool _obscureText = true;
+
+  @override
+  Widget build(BuildContext context) {
+    return new TextFormField(
+      key: widget.fieldKey,
+      obscureText: _obscureText,
+      maxLength: 8,
+      onSaved: widget.onSaved,
+      validator: widget.validator,
+      onFieldSubmitted: widget.onFieldSubmitted,
+      decoration: new InputDecoration(
+        border: const UnderlineInputBorder(),
+        filled: true,
+        hintText: widget.hintText,
+        labelText: widget.labelText,
+        helperText: widget.helperText,
+        suffixIcon: new GestureDetector(
+          onTap: () {
+            setState(() {
+              _obscureText = !_obscureText;
+            });
+          },
+          child: new Icon(_obscureText ? Icons.visibility : Icons.visibility_off),
+        ),
+      ),
+    );
+  }
+}
+
 class TextFormFieldDemoState extends State<TextFormFieldDemo> {
   final GlobalKey<ScaffoldState> _scaffoldKey = new GlobalKey<ScaffoldState>();
 
@@ -36,6 +90,7 @@ class TextFormFieldDemoState extends State<TextFormFieldDemo> {
 
   bool _autovalidate = false;
   bool _formWasEdited = false;
+
   final GlobalKey<FormState> _formKey = new GlobalKey<FormState>();
   final GlobalKey<FormFieldState<String>> _passwordFieldKey = new GlobalKey<FormFieldState<String>>();
   final _UsNumberTextInputFormatter _phoneNumberFormatter = new _UsNumberTextInputFormatter();
@@ -64,7 +119,7 @@ class TextFormFieldDemoState extends State<TextFormFieldDemo> {
     _formWasEdited = true;
     final RegExp phoneExp = new RegExp(r'^\(\d\d\d\) \d\d\d\-\d\d\d\d$');
     if (!phoneExp.hasMatch(value))
-      return '(###) ###-#### - Please enter a valid US phone number.';
+      return '(###) ###-#### - Enter a US phone number.';
     return null;
   }
 
@@ -72,9 +127,9 @@ class TextFormFieldDemoState extends State<TextFormFieldDemo> {
     _formWasEdited = true;
     final FormFieldState<String> passwordField = _passwordFieldKey.currentState;
     if (passwordField.value == null || passwordField.value.isEmpty)
-      return 'Please choose a password.';
+      return 'Please enter a password.';
     if (passwordField.value != value)
-      return 'Passwords don\'t match';
+      return 'The passwords don\'t match';
     return null;
   }
 
@@ -118,11 +173,16 @@ class TextFormFieldDemoState extends State<TextFormFieldDemo> {
           key: _formKey,
           autovalidate: _autovalidate,
           onWillPop: _warnUserAboutInvalidData,
-          child: new ListView(
+          child: new SingleChildScrollView(
             padding: const EdgeInsets.symmetric(horizontal: 16.0),
+            child: new Column(
+              crossAxisAlignment: CrossAxisAlignment.stretch,
               children: <Widget>[
+                const SizedBox(height: 24.0),
                 new TextFormField(
                   decoration: const InputDecoration(
+                    border: const UnderlineInputBorder(),
+                    filled: true,
                     icon: const Icon(Icons.person),
                     hintText: 'What do people call you?',
                     labelText: 'Name *',
@@ -130,12 +190,15 @@ class TextFormFieldDemoState extends State<TextFormFieldDemo> {
                   onSaved: (String value) { person.name = value; },
                   validator: _validateName,
                 ),
+                const SizedBox(height: 24.0),
                 new TextFormField(
                   decoration: const InputDecoration(
+                    border: const UnderlineInputBorder(),
+                    filled: true,
                     icon: const Icon(Icons.phone),
                     hintText: 'Where can we reach you?',
                     labelText: 'Phone Number *',
-                  prefixText: '+1'
+                    prefixText: '+1',
                   ),
                   keyboardType: TextInputType.phone,
                   onSaved: (String value) { person.phoneNumber = value; },
@@ -147,8 +210,11 @@ class TextFormFieldDemoState extends State<TextFormFieldDemo> {
                     _phoneNumberFormatter,
                   ],
                 ),
+                const SizedBox(height: 24.0),
                 new TextFormField(
                   decoration: const InputDecoration(
+                    border: const UnderlineInputBorder(),
+                    filled: true,
                     icon: const Icon(Icons.email),
                     hintText: 'Your email address',
                     labelText: 'E-mail',
@@ -156,17 +222,21 @@ class TextFormFieldDemoState extends State<TextFormFieldDemo> {
                   keyboardType: TextInputType.emailAddress,
                   onSaved: (String value) { person.email = value; },
                 ),
+                const SizedBox(height: 24.0),
                 new TextFormField(
                   decoration: const InputDecoration(
+                    border: const OutlineInputBorder(),
                     hintText: 'Tell us about yourself',
-                  helperText: 'Keep it short, this is just a demo',
+                    helperText: 'Keep it short, this is just a demo.',
                     labelText: 'Life story',
                   ),
                   maxLines: 3,
                 ),
+                const SizedBox(height: 24.0),
                 new TextFormField(
                   keyboardType: TextInputType.number,
                   decoration: const InputDecoration(
+                    border: const OutlineInputBorder(),
                     labelText: 'Salary',
                     prefixText: '\$',
                     suffixText: 'USD',
@@ -174,50 +244,43 @@ class TextFormFieldDemoState extends State<TextFormFieldDemo> {
                   ),
                   maxLines: 1,
                 ),
-              new Row(
-                crossAxisAlignment: CrossAxisAlignment.start,
-                children: <Widget>[
-                  new Expanded(
-                    child: new TextFormField(
-                      key: _passwordFieldKey,
-                      decoration: const InputDecoration(
-                        hintText: 'How do you log in?',
-                        labelText: 'New Password *',
-                      ),
-                      obscureText: true,
+                const SizedBox(height: 24.0),
+                new PasswordField(
+                  fieldKey: _passwordFieldKey,
+                  helperText: 'No more than 8 characters.',
+                  labelText: 'Password *',
                   onSaved: (String value) { person.password = value; },
                 ),
-                  ),
-                  const SizedBox(width: 16.0),
-                  new Expanded(
-                    child: new TextFormField(
+                const SizedBox(height: 24.0),
+                new TextFormField(
                   decoration: const InputDecoration(
-                        hintText: 'How do you log in?',
-                        labelText: 'Re-type Password *',
+                    border: const UnderlineInputBorder(),
+                    filled: true,
+                    labelText: 'Re-type password',
                   ),
+                  maxLength: 8,
+                  onFieldSubmitted: (String value) { person.password = value; },
                   obscureText: true,
-                      onFieldSubmitted: (String value) { _handleSubmitted(); },
                   validator: _validatePassword,
                 ),
-                  ),
-                ],
-              ),
-              new Container(
-                padding: const EdgeInsets.all(20.0),
-                alignment: Alignment.center,
+                const SizedBox(height: 24.0),
+                new Center(
                   child: new RaisedButton(
                     child: const Text('SUBMIT'),
                     onPressed: _handleSubmitted,
                   ),
                 ),
-              new Container(
-                padding: const EdgeInsets.only(top: 20.0),
-                child: new Text('* indicates required field', style: Theme.of(context).textTheme.caption),
+                const SizedBox(height: 24.0),
+                new Text(
+                  '* indicates required field',
+                  style: Theme.of(context).textTheme.caption
                 ),
+                const SizedBox(height: 24.0),
               ],
             ),
           ),
         ),
+      ),
     );
   }
 }

examples/flutter_gallery/test/demo/material/text_form_field_demo_test.dart

@@ -16,21 +16,36 @@ void main() {
     final Finder nameField = find.widgetWithText(TextFormField, 'Name *');
     expect(nameField, findsOneWidget);
 
+    final Finder passwordField = find.widgetWithText(TextFormField, 'Password *');
+    expect(passwordField, findsOneWidget);
+
     await tester.enterText(nameField, '');
+    // The submit button isn't initially visible. Drag it into view so that
+    // it will see the tap.
+    await tester.drag(nameField, const Offset(0.0, -1200.0));
+    await tester.pumpAndSettle();
     await tester.tap(submitButton);
-    await tester.pump();
+    await tester.pumpAndSettle();
+
+    // Now drag the password field (the submit button will be obscured by
+    // the snackbar) and expose the name field again.
+    await tester.drag(passwordField, const Offset(0.0, 1200.0));
+    await tester.pumpAndSettle();
     expect(find.text('Name is required.'), findsOneWidget);
     expect(find.text('Please enter only alphabetical characters.'), findsNothing);
-
     await tester.enterText(nameField, '#');
+
+    // Make the submit button visible again (by dragging the name field), so
+    // it will see the tap.
+    await tester.drag(nameField, const Offset(0.0, -1200.0));
     await tester.tap(submitButton);
-    await tester.pump();
+    await tester.pumpAndSettle();
     expect(find.text('Name is required.'), findsNothing);
     expect(find.text('Please enter only alphabetical characters.'), findsOneWidget);
 
     await tester.enterText(nameField, 'Jane Doe');
     await tester.tap(submitButton);
-    await tester.pump();
+    await tester.pumpAndSettle();
     expect(find.text('Name is required.'), findsNothing);
     expect(find.text('Please enter only alphabetical characters.'), findsNothing);
   });

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

@@ -60,7 +60,9 @@ class TextFormField extends FormField<String> {
     bool autofocus: false,
     bool obscureText: false,
     bool autocorrect: true,
+    bool maxLengthEnforced: true,
     int maxLines: 1,
+    int maxLength,
     ValueChanged<String> onFieldSubmitted,
     FormFieldSetter<String> onSaved,
     FormFieldValidator<String> validator,
@@ -71,7 +73,9 @@ class TextFormField extends FormField<String> {
        assert(autofocus != null),
        assert(obscureText != null),
        assert(autocorrect != null),
+       assert(maxLengthEnforced != null),
        assert(maxLines == null || maxLines > 0),
+       assert(maxLength == null || maxLength > 0),
        super(
     key: key,
     initialValue: controller != null ? controller.text : (initialValue ?? ''),
@@ -91,7 +95,9 @@ class TextFormField extends FormField<String> {
         autofocus: autofocus,
         obscureText: obscureText,
         autocorrect: autocorrect,
+        maxLengthEnforced: maxLengthEnforced,
         maxLines: maxLines,
+        maxLength: maxLength,
         onChanged: field.onChanged,
         onSubmitted: onFieldSubmitted,
         inputFormatters: inputFormatters,