Add support for extending selection to paragraph on ctrl + shift + arrow...

Add support for extending selection to paragraph on ctrl + shift + arrow up/down on Non-Apple platforms (#120151)

* Add support for extending selection to paragraph on ctrl + shift + arrow up/down for common keyboard actions

* Add ctrl + shift + arrow up/down common text editing shortcuts/actions

* fix analyzer

---------
Co-authored-by: Renzo Olivares <roliv@google.com>

packages/flutter/lib/src/widgets/default_text_editing_shortcuts.dart

@@ -207,6 +207,9 @@ class DefaultTextEditingShortcuts extends StatelessWidget {
     const SingleActivator(LogicalKeyboardKey.arrowLeft, shift: true, control: true): const ExtendSelectionToNextWordBoundaryIntent(forward: false, collapseSelection: false),
     const SingleActivator(LogicalKeyboardKey.arrowRight, shift: true, control: true): const ExtendSelectionToNextWordBoundaryIntent(forward: true, collapseSelection: false),
 
+    const SingleActivator(LogicalKeyboardKey.arrowUp, shift: true, control: true): const ExtendSelectionToNextParagraphBoundaryIntent(forward: false, collapseSelection: false),
+    const SingleActivator(LogicalKeyboardKey.arrowDown, shift: true, control: true): const ExtendSelectionToNextParagraphBoundaryIntent(forward: true, collapseSelection: false),
+
     // Page Up / Down: Move selection by page.
     const SingleActivator(LogicalKeyboardKey.pageUp): const ExtendSelectionVerticallyToAdjacentPageIntent(forward: false, collapseSelection: true),
     const SingleActivator(LogicalKeyboardKey.pageDown): const ExtendSelectionVerticallyToAdjacentPageIntent(forward: true, collapseSelection: true),

packages/flutter/lib/src/widgets/editable_text.dart

@@ -4424,6 +4424,7 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
     ExtendSelectionByCharacterIntent: _makeOverridable(_UpdateTextSelectionAction<ExtendSelectionByCharacterIntent>(this, _characterBoundary, _moveBeyondTextBoundary, ignoreNonCollapsedSelection: false)),
     ExtendSelectionByPageIntent: _makeOverridable(CallbackAction<ExtendSelectionByPageIntent>(onInvoke: _extendSelectionByPage)),
     ExtendSelectionToNextWordBoundaryIntent: _makeOverridable(_UpdateTextSelectionAction<ExtendSelectionToNextWordBoundaryIntent>(this, _nextWordBoundary, _moveBeyondTextBoundary, ignoreNonCollapsedSelection: true)),
+    ExtendSelectionToNextParagraphBoundaryIntent : _makeOverridable(_UpdateTextSelectionAction<ExtendSelectionToNextParagraphBoundaryIntent>(this, _paragraphBoundary, _moveBeyondTextBoundary, ignoreNonCollapsedSelection: true)),
     ExtendSelectionToLineBreakIntent: _makeOverridable(_UpdateTextSelectionAction<ExtendSelectionToLineBreakIntent>(this, _linebreak, _moveToTextBoundary, ignoreNonCollapsedSelection: true)),
     ExtendSelectionVerticallyToAdjacentLineIntent: _makeOverridable(_verticalSelectionUpdateAction),
     ExtendSelectionVerticallyToAdjacentPageIntent: _makeOverridable(_verticalSelectionUpdateAction),

packages/flutter/lib/src/widgets/text_editing_intents.dart

@@ -221,12 +221,25 @@ class ExtendSelectionVerticallyToAdjacentPageIntent extends DirectionalCaretMove
   }) : super(forward, collapseSelection);
 }
 
+/// Extends, or moves the current selection from the current
+/// [TextSelection.extent] position to the previous or the next paragraph
+/// boundary.
+class ExtendSelectionToNextParagraphBoundaryIntent extends DirectionalCaretMovementIntent {
+  /// Creates an [ExtendSelectionToNextParagraphBoundaryIntent].
+  const ExtendSelectionToNextParagraphBoundaryIntent({
+    required bool forward,
+    required bool collapseSelection,
+  }) : super(forward, collapseSelection);
+}
+
 /// Extends, or moves the current selection from the current
 /// [TextSelection.extent] position to the previous or the next paragraph
 /// boundary depending on the [forward] parameter.
 ///
-/// This [Intent] collapses the selection when the order of [TextSelection.base]
-/// and [TextSelection.extent] would reverse.
+/// This [Intent] typically has the same effect as an
+/// [ExtendSelectionToNextParagraphBoundaryIntent], except it collapses the selection
+/// when the order of [TextSelection.base] and [TextSelection.extent] would
+/// reverse.
 ///
 /// This is typically only used on MacOS.
 class ExtendSelectionToNextParagraphBoundaryOrCaretLocationIntent extends DirectionalCaretMovementIntent {

packages/flutter/test/widgets/editable_text_test.dart

@@ -6723,7 +6723,7 @@ void main() {
     );
     expect(controller.text, equals(testText), reason: 'on $platform');
 
-    final bool platformCanSelectByParagraph = defaultTargetPlatform == TargetPlatform.iOS || defaultTargetPlatform == TargetPlatform.macOS;
+    final bool platformIsApple = defaultTargetPlatform == TargetPlatform.iOS || defaultTargetPlatform == TargetPlatform.macOS;
     // Move down one paragraph.
     await sendKeys(
       tester,
@@ -6738,9 +6738,9 @@ void main() {
     expect(
       selection,
       equals(
-        TextSelection(
+        const TextSelection(
           baseOffset: 10,
-          extentOffset: platformCanSelectByParagraph ? 20 : 10,
+          extentOffset: 20,
         ),
       ),
       reason: 'on $platform',
@@ -6760,9 +6760,9 @@ void main() {
     expect(
       selection,
       equals(
-        TextSelection(
+        const TextSelection(
           baseOffset: 10,
-          extentOffset: platformCanSelectByParagraph ? 36 : 10,
+          extentOffset: 36,
         ),
       ),
       reason: 'on $platform',
@@ -6782,9 +6782,9 @@ void main() {
     expect(
       selection,
       equals(
-        TextSelection(
+        const TextSelection(
           baseOffset: 10,
-          extentOffset: platformCanSelectByParagraph ? 55 : 10,
+          extentOffset: 55,
         ),
       ),
       reason: 'on $platform',
@@ -6804,9 +6804,9 @@ void main() {
     expect(
       selection,
       equals(
-        TextSelection(
+        const TextSelection(
           baseOffset: 10,
-          extentOffset: platformCanSelectByParagraph ? 36 : 10,
+          extentOffset: 36,
         ),
       ),
       reason: 'on $platform',
@@ -6826,15 +6826,16 @@ void main() {
     expect(
       selection,
       equals(
-        TextSelection(
+        const TextSelection(
           baseOffset: 10,
-          extentOffset: platformCanSelectByParagraph ? 20 : 10,
+          extentOffset: 20,
         ),
       ),
       reason: 'on $platform',
     );
 
-    // Move up back to the origin.
+    // Move up. This will collapse the selection to the origin on Apple platforms, and
+    // extend to the previous paragraph boundary on other platforms.
     await sendKeys(
       tester,
       <LogicalKeyboardKey>[
@@ -6850,13 +6851,15 @@ void main() {
       equals(
         TextSelection(
           baseOffset: 10,
-          extentOffset: platformCanSelectByParagraph ? 10 : 10,
+          extentOffset: platformIsApple ? 10 : 0,
         ),
       ),
       reason: 'on $platform',
     );
 
-    // Move up, extending the selection backwards to the next paragraph.
+    // Move up, extending the selection backwards to the previous paragraph on Apple platforms.
+    // On other platforms this does nothing since our extent is already at 0 from the previous
+    // set of keys sent.
     await sendKeys(
       tester,
       <LogicalKeyboardKey>[
@@ -6867,12 +6870,36 @@ void main() {
       targetPlatform: defaultTargetPlatform,
     );
 
+    expect(
+      selection,
+      equals(
+        const TextSelection(
+          baseOffset: 10,
+          extentOffset: 0,
+        ),
+      ),
+      reason: 'on $platform',
+    );
+
+    // Move down, collapsing the selection to the origin on Apple platforms.
+    // On other platforms this moves the selection's extent to the next paragraph boundary.
+    await sendKeys(
+      tester,
+      <LogicalKeyboardKey>[
+        LogicalKeyboardKey.arrowDown,
+      ],
+      shift: true,
+      wordModifier: true,
+      targetPlatform: defaultTargetPlatform,
+    );
+
     expect(
       selection,
       equals(
         TextSelection(
           baseOffset: 10,
-          extentOffset: platformCanSelectByParagraph ? 0 : 10,
+          extentOffset: platformIsApple ? 10 : 20,
+          affinity: platformIsApple ? TextAffinity.upstream : TextAffinity.downstream,
         ),
       ),
       reason: 'on $platform',