Selecting spaces (#68227)

When attempting to select a space on mobile, Flutter will try to select the word before the space too, if one exists.

packages/flutter/lib/src/rendering/editable.dart

@@ -1930,6 +1930,40 @@ class RenderEditable extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
     // If text is obscured, the entire sentence should be treated as one word.
     if (obscureText) {
       return TextSelection(baseOffset: 0, extentOffset: _plainText.length);
+    // If the word is a space, on iOS try to select the previous word instead.
+    } else if (text?.text != null
+        && _isWhitespace(text!.text!.codeUnitAt(position.offset))
+        && position.offset > 0) {
+      assert(defaultTargetPlatform != null);
+      switch (defaultTargetPlatform) {
+        case TargetPlatform.iOS:
+          int startIndex = position.offset - 1;
+          while (startIndex > 0
+              && (_isWhitespace(text!.text!.codeUnitAt(startIndex))
+              || text!.text! == '\u200e' || text!.text! == '\u200f')) {
+            startIndex--;
+          }
+          if (startIndex > 0) {
+            final TextPosition positionBeforeSpace = TextPosition(
+              offset: startIndex,
+              affinity: position.affinity,
+            );
+            final TextRange wordBeforeSpace = _textPainter.getWordBoundary(
+              positionBeforeSpace,
+            );
+            startIndex = wordBeforeSpace.start;
+          }
+          return TextSelection(
+            baseOffset: startIndex,
+            extentOffset: position.offset,
+          );
+        case TargetPlatform.android:
+        case TargetPlatform.fuchsia:
+        case TargetPlatform.macOS:
+        case TargetPlatform.linux:
+        case TargetPlatform.windows:
+          break;
+      }
     }
     return TextSelection(baseOffset: word.start, extentOffset: word.end);
   }

packages/flutter/test/cupertino/text_field_test.dart

@@ -1720,6 +1720,126 @@ void main() {
     },
   );
 
+  testWidgets('double tapping a space selects the previous word on iOS', (WidgetTester tester) async {
+    final TextEditingController controller = TextEditingController(
+      text: ' blah blah  \n  blah',
+    );
+    await tester.pumpWidget(
+      CupertinoApp(
+        home: Center(
+          child: CupertinoTextField(
+            controller: controller,
+            maxLines: 2,
+          ),
+        ),
+      ),
+    );
+
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, -1);
+    expect(controller.value.selection.extentOffset, -1);
+
+    // Put the cursor at the end of the field.
+    await tester.tapAt(textOffsetToPosition(tester, 19));
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 19);
+    expect(controller.value.selection.extentOffset, 19);
+
+    // Double tapping the second space selects the previous word.
+    await tester.pump(const Duration(milliseconds: 500));
+    await tester.tapAt(textOffsetToPosition(tester, 5));
+    await tester.pump(const Duration(milliseconds: 50));
+    await tester.tapAt(textOffsetToPosition(tester, 5));
+    await tester.pumpAndSettle();
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 1);
+    expect(controller.value.selection.extentOffset, 5);
+
+    // Put the cursor at the end of the field.
+    await tester.tapAt(textOffsetToPosition(tester, 19));
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 19);
+    expect(controller.value.selection.extentOffset, 19);
+
+    // Double tapping the first space selects the space.
+    await tester.pump(const Duration(milliseconds: 500));
+    await tester.tapAt(textOffsetToPosition(tester, 0));
+    await tester.pump(const Duration(milliseconds: 50));
+    await tester.tapAt(textOffsetToPosition(tester, 0));
+    await tester.pumpAndSettle();
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 0);
+    expect(controller.value.selection.extentOffset, 1);
+
+    // Put the cursor at the end of the field.
+    await tester.tapAt(textOffsetToPosition(tester, 19));
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 19);
+    expect(controller.value.selection.extentOffset, 19);
+
+    // Double tapping the last space selects all previous contiguous spaces on
+    // both lines and the previous word.
+    await tester.pump(const Duration(milliseconds: 500));
+    await tester.tapAt(textOffsetToPosition(tester, 14));
+    await tester.pump(const Duration(milliseconds: 50));
+    await tester.tapAt(textOffsetToPosition(tester, 14));
+    await tester.pumpAndSettle();
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 6);
+    expect(controller.value.selection.extentOffset, 14);
+  }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS }));
+
+  testWidgets('double tapping a space selects the space on Mac', (WidgetTester tester) async {
+    final TextEditingController controller = TextEditingController(
+      text: ' blah blah',
+    );
+    await tester.pumpWidget(
+      CupertinoApp(
+        home: Center(
+          child: CupertinoTextField(
+            controller: controller,
+          ),
+        ),
+      ),
+    );
+
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, -1);
+    expect(controller.value.selection.extentOffset, -1);
+
+    // Put the cursor at the end of the field.
+    await tester.tapAt(textOffsetToPosition(tester, 10));
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 10);
+    expect(controller.value.selection.extentOffset, 10);
+
+    // Double tapping the second space selects it.
+    await tester.pump(const Duration(milliseconds: 500));
+    await tester.tapAt(textOffsetToPosition(tester, 5));
+    await tester.pump(const Duration(milliseconds: 50));
+    await tester.tapAt(textOffsetToPosition(tester, 5));
+    await tester.pumpAndSettle();
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 5);
+    expect(controller.value.selection.extentOffset, 6);
+
+    // Put the cursor at the end of the field.
+    await tester.tapAt(textOffsetToPosition(tester, 10));
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 10);
+    expect(controller.value.selection.extentOffset, 10);
+
+    // Double tapping the first space selects it.
+    await tester.pump(const Duration(milliseconds: 500));
+    await tester.tapAt(textOffsetToPosition(tester, 0));
+    await tester.pump(const Duration(milliseconds: 50));
+    await tester.tapAt(textOffsetToPosition(tester, 0));
+    await tester.pumpAndSettle();
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 0);
+    expect(controller.value.selection.extentOffset, 1);
+  }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.macOS }));
+
   testWidgets(
     'An obscured CupertinoTextField is not selectable when disabled',
     (WidgetTester tester) async {

packages/flutter/test/material/text_field_test.dart

@@ -7044,6 +7044,129 @@ void main() {
       expect(find.byType(CupertinoButton), findsNWidgets(3));
   }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS,  TargetPlatform.macOS }));
 
+  testWidgets('double tapping a space selects the previous word on iOS', (WidgetTester tester) async {
+    final TextEditingController controller = TextEditingController(
+      text: ' blah blah  \n  blah',
+    );
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: Center(
+            child: TextField(
+              controller: controller,
+            ),
+          ),
+        ),
+      ),
+    );
+
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, -1);
+    expect(controller.value.selection.extentOffset, -1);
+
+    // Put the cursor at the end of the field.
+    await tester.tapAt(textOffsetToPosition(tester, 19));
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 19);
+    expect(controller.value.selection.extentOffset, 19);
+
+    // Double tapping does the same thing.
+    await tester.pump(const Duration(milliseconds: 500));
+    await tester.tapAt(textOffsetToPosition(tester, 5));
+    await tester.pump(const Duration(milliseconds: 50));
+    await tester.tapAt(textOffsetToPosition(tester, 5));
+    await tester.pumpAndSettle();
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.extentOffset, 5);
+    expect(controller.value.selection.baseOffset, 1);
+
+    // Put the cursor at the end of the field.
+    await tester.tapAt(textOffsetToPosition(tester, 19));
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 19);
+    expect(controller.value.selection.extentOffset, 19);
+
+    // Double tapping does the same thing for the first space.
+    await tester.pump(const Duration(milliseconds: 500));
+    await tester.tapAt(textOffsetToPosition(tester, 0));
+    await tester.pump(const Duration(milliseconds: 50));
+    await tester.tapAt(textOffsetToPosition(tester, 0));
+    await tester.pumpAndSettle();
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 0);
+    expect(controller.value.selection.extentOffset, 1);
+
+    // Put the cursor at the end of the field.
+    await tester.tapAt(textOffsetToPosition(tester, 19));
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 19);
+    expect(controller.value.selection.extentOffset, 19);
+
+    // Double tapping the last space selects all previous contiguous spaces on
+    // both lines and the previous word.
+    await tester.pump(const Duration(milliseconds: 500));
+    await tester.tapAt(textOffsetToPosition(tester, 14));
+    await tester.pump(const Duration(milliseconds: 50));
+    await tester.tapAt(textOffsetToPosition(tester, 14));
+    await tester.pumpAndSettle();
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 6);
+    expect(controller.value.selection.extentOffset, 14);
+  }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS }));
+
+  testWidgets('selecting a space selects the space on non-iOS platforms', (WidgetTester tester) async {
+    final TextEditingController controller = TextEditingController(
+      text: ' blah blah',
+    );
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: Center(
+            child: TextField(
+              controller: controller,
+            ),
+          ),
+        ),
+      ),
+    );
+
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, -1);
+    expect(controller.value.selection.extentOffset, -1);
+
+    // Put the cursor at the end of the field.
+    await tester.tapAt(textOffsetToPosition(tester, 10));
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 10);
+    expect(controller.value.selection.extentOffset, 10);
+
+    // Double tapping the second space selects it.
+    await tester.pump(const Duration(milliseconds: 500));
+    await tester.tapAt(textOffsetToPosition(tester, 5));
+    await tester.pump(const Duration(milliseconds: 50));
+    await tester.tapAt(textOffsetToPosition(tester, 5));
+    await tester.pumpAndSettle();
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 5);
+    expect(controller.value.selection.extentOffset, 6);
+
+    // Put the cursor at the end of the field.
+    await tester.tapAt(textOffsetToPosition(tester, 10));
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 10);
+    expect(controller.value.selection.extentOffset, 10);
+
+    // Double tapping the second space selects it.
+    await tester.pump(const Duration(milliseconds: 500));
+    await tester.tapAt(textOffsetToPosition(tester, 0));
+    await tester.pump(const Duration(milliseconds: 50));
+    await tester.tapAt(textOffsetToPosition(tester, 0));
+    await tester.pumpAndSettle();
+    expect(controller.value.selection, isNotNull);
+    expect(controller.value.selection.baseOffset, 0);
+    expect(controller.value.selection.extentOffset, 1);
+  }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.macOS,  TargetPlatform.windows, TargetPlatform.linux, TargetPlatform.fuchsia, TargetPlatform.android }));
+
   testWidgets('force press does not select a word', (WidgetTester tester) async {
     final TextEditingController controller = TextEditingController(
       text: 'Atwater Peel Sherbrooke Bonaventure',