[Material] Update some semantics for time picker controls (#66652)

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

@@ -560,6 +560,7 @@ class _DayPeriodControl extends StatelessWidget {
         onTap: Feedback.wrapForTap(() => _setAm(context), context),
         child: Semantics(
           selected: amSelected,
+          button: true,
           child: Center(
             child: Text(
               materialLocalizations.anteMeridiemAbbreviation,
@@ -577,6 +578,7 @@ class _DayPeriodControl extends StatelessWidget {
         onTap: Feedback.wrapForTap(() => _setPm(context), context),
         child: Semantics(
           selected: pmSelected,
+          button: true,
           child: Center(
             child: Text(
               materialLocalizations.postMeridiemAbbreviation,
@@ -1522,6 +1524,7 @@ class _HourTextField extends StatelessWidget {
       selectedTime: selectedTime,
       isHour: true,
       style: style,
+      semanticHintText: MaterialLocalizations.of(context).timePickerHourLabel,
       validator: validator,
       onSavedSubmitted: onSavedSubmitted,
       onChanged: onChanged,
@@ -1549,6 +1552,7 @@ class _MinuteTextField extends StatelessWidget {
       selectedTime: selectedTime,
       isHour: false,
       style: style,
+      semanticHintText: MaterialLocalizations.of(context).timePickerMinuteLabel,
       validator: validator,
       onSavedSubmitted: onSavedSubmitted,
     );
@@ -1561,6 +1565,7 @@ class _HourMinuteTextField extends StatefulWidget {
     @required this.selectedTime,
     @required this.isHour,
     @required this.style,
+    @required this.semanticHintText,
     @required this.validator,
     @required this.onSavedSubmitted,
     this.onChanged,
@@ -1569,6 +1574,7 @@ class _HourMinuteTextField extends StatefulWidget {
   final TimeOfDay selectedTime;
   final bool isHour;
   final TextStyle style;
+  final String semanticHintText;
   final FormFieldValidator<String> validator;
   final ValueChanged<String> onSavedSubmitted;
   final ValueChanged<String> onChanged;
@@ -1636,10 +1642,14 @@ class _HourMinuteTextFieldState extends State<_HourMinuteTextField> {
       );
     }
     final Color unfocusedFillColor = timePickerTheme.hourMinuteColor ?? colorScheme.onSurface.withOpacity(0.12);
+    // If screen reader is in use, make the hint text say hours/minutes.
+    // Otherwise, remove the hint text when focused because the centered cursor
+    // appears odd above the hint text.
+    final String hintText = MediaQuery.of(context).accessibleNavigation
+        ? widget.semanticHintText
+        : (focusNode.hasFocus ? null : _formattedValue);
     inputDecoration = inputDecoration.copyWith(
-      // Remove the hint text when focused because the centered cursor appears
-      // odd above the hint text.
-      hintText: focusNode.hasFocus ? null : _formattedValue,
+      hintText: hintText,
       fillColor: focusNode.hasFocus ? Colors.transparent : inputDecorationTheme?.fillColor ?? unfocusedFillColor,
     );
 

packages/flutter/test/material/time_picker_test.dart

@@ -324,8 +324,22 @@ void _tests() {
     final SemanticsTester semantics = SemanticsTester(tester);
     await mediaQueryBoilerplate(tester, false);
 
-    expect(semantics, includesNodeWith(label: 'AM', actions: <SemanticsAction>[SemanticsAction.tap]));
-    expect(semantics, includesNodeWith(label: 'PM', actions: <SemanticsAction>[SemanticsAction.tap]));
+    expect(
+      semantics,
+      includesNodeWith(
+        label: 'AM',
+        actions: <SemanticsAction>[SemanticsAction.tap],
+        flags: <SemanticsFlag>[SemanticsFlag.isButton, SemanticsFlag.isSelected, SemanticsFlag.isFocusable],
+      ),
+    );
+    expect(
+      semantics,
+      includesNodeWith(
+        label: 'PM',
+        actions: <SemanticsAction>[SemanticsAction.tap],
+        flags: <SemanticsFlag>[SemanticsFlag.isButton, SemanticsFlag.isFocusable],
+      ),
+    );
 
     semantics.dispose();
   });
@@ -349,6 +363,32 @@ void _tests() {
     semantics.dispose();
   });
 
+  testWidgets('provides semantics information for text fields', (WidgetTester tester) async {
+    final SemanticsTester semantics = SemanticsTester(tester);
+    await mediaQueryBoilerplate(tester, true, entryMode: TimePickerEntryMode.input, accessibleNavigation: true);
+
+    expect(
+      semantics,
+      includesNodeWith(
+        label: 'Hour',
+        value: '07',
+        actions: <SemanticsAction>[SemanticsAction.tap],
+        flags: <SemanticsFlag>[SemanticsFlag.isTextField, SemanticsFlag.isMultiline],
+      ),
+    );
+    expect(
+      semantics,
+      includesNodeWith(
+        label: 'Minute',
+        value: '00',
+        actions: <SemanticsAction>[SemanticsAction.tap],
+        flags: <SemanticsFlag>[SemanticsFlag.isTextField, SemanticsFlag.isMultiline],
+      ),
+    );
+
+    semantics.dispose();
+  });
+
   testWidgets('can increment and decrement hours', (WidgetTester tester) async {
     final SemanticsTester semantics = SemanticsTester(tester);
 
@@ -840,6 +880,7 @@ Future<void> mediaQueryBoilerplate(
       double textScaleFactor = 1.0,
       TimePickerEntryMode entryMode = TimePickerEntryMode.dial,
       String helpText,
+      bool accessibleNavigation = false,
     }) async {
   await tester.pumpWidget(
     Localizations(
@@ -852,6 +893,7 @@ Future<void> mediaQueryBoilerplate(
         data: MediaQueryData(
           alwaysUse24HourFormat: alwaysUse24HourFormat,
           textScaleFactor: textScaleFactor,
+          accessibleNavigation: accessibleNavigation,
         ),
         child: Material(
           child: Directionality(