Pipe onsubmit for text form fields (#13687)

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

@@ -184,6 +184,7 @@ class TextFormFieldDemoState extends State<TextFormFieldDemo> {
                         labelText: 'Re-type Password *',
                       ),
                       obscureText: true,
+                      onFieldSubmitted: (String value) { _handleSubmitted(); },
                       validator: _validatePassword,
                     ),
                   ),

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

@@ -53,6 +53,7 @@ class TextFormField extends FormField<String> {
     bool obscureText: false,
     bool autocorrect: true,
     int maxLines: 1,
+    ValueChanged<String> onFieldSubmitted,
     FormFieldSetter<String> onSaved,
     FormFieldValidator<String> validator,
     List<TextInputFormatter> inputFormatters,
@@ -82,6 +83,7 @@ class TextFormField extends FormField<String> {
         autocorrect: autocorrect,
         maxLines: maxLines,
         onChanged: field.onChanged,
+        onSubmitted: onFieldSubmitted,
         inputFormatters: inputFormatters,
       );
     },

packages/flutter/test/material/text_form_field_test.dart

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 void main() {
@@ -27,4 +28,25 @@ void main() {
     final TextField textFieldWidget = tester.widget(textFieldFinder);
     expect(textFieldWidget.textAlign, alignment);
   });
+
+  testWidgets('onFieldSubmit callbacks are called', (WidgetTester tester) async {
+    bool _called = false;
+
+    await tester.pumpWidget(
+      new MaterialApp(
+        home: new Material(
+          child: new Center(
+            child: new TextFormField(
+              onFieldSubmitted: (String value) { _called = true; },
+            ),
+          ),
+        ),
+      ),
+    );
+
+    await tester.showKeyboard(find.byType(TextField));
+    tester.testTextInput.receiveAction(TextInputAction.done);
+    await tester.pump();
+    expect(_called, true);
+  });
 }

packages/flutter_test/lib/src/test_text_input.dart

@@ -106,6 +106,27 @@ class TestTextInput {
     ));
   }
 
+  /// Simulates the user pressing one of the [TextInputAction] buttons.
+  /// Does not check that the [TextInputAction] performed is an acceptable one
+  /// based on the `inputAction` [setClientArgs].
+  void receiveAction(TextInputAction action) {
+    // Not using the `expect` function because in the case of a FlutterDriver
+    // test this code does not run in a package:test test zone.
+    if (_client == 0) {
+      throw new TestFailure('_client must be non-zero');
+    }
+    BinaryMessages.handlePlatformMessage(
+      SystemChannels.textInput.name,
+      SystemChannels.textInput.codec.encodeMethodCall(
+        new MethodCall(
+          'TextInputClient.performAction',
+          <dynamic>[_client, action.toString()],
+        ),
+      ),
+      (ByteData data) { /* response from framework is discarded */ },
+    );
+  }
+
   /// Simulates the user hiding the onscreen keyboard.
   void hide() {
     _isVisible = false;