use null aware operators for function invocations (#79049)

2024-10-13 03:32:55 +00:00 · 2021-03-26 17:34:03 +01:00 · 2021-03-26 17:34:03 +01:00 · e384ca7979
parent bc2c7954db
commit e384ca7979
48 changed files with 138 additions and 320 deletions
--- a/dev/integration_tests/flutter_gallery/lib/demo/shrine/category_menu_page.dart
+++ b/dev/integration_tests/flutter_gallery/lib/demo/shrine/category_menu_page.dart
@ -25,9 +25,7 @@ class CategoryMenuPage extends StatelessWidget {
          GestureDetector(
            onTap: () {
              model.setCategory(category);
-              if (onCategoryTap != null) {
-                onCategoryTap!();
-              }
+              onCategoryTap?.call();
            },
            child: model.selectedCategory == category
              ? Column(
--- a/dev/integration_tests/flutter_gallery/lib/demo/transformations/transformations_demo_color_picker.dart
+++ b/dev/integration_tests/flutter_gallery/lib/demo/transformations/transformations_demo_color_picker.dart
@ -27,9 +27,7 @@ class ColorPicker extends StatelessWidget {
          color: color,
          selected: color == selectedColor,
          onTap: () {
-            if (onColorSelection != null) {
-              onColorSelection!(color);
-            }
+            onColorSelection?.call(color);
          },
        );
      }).toList(),
@ -59,9 +57,7 @@ class _ColorPickerSwatch extends StatelessWidget {
      child: RawMaterialButton(
        fillColor: color,
        onPressed: () {
-          if (onTap != null) {
-            onTap!();
-          }
+          onTap?.call();
        },
        child: !selected ? null : const Icon(
          Icons.check,
--- a/dev/integration_tests/flutter_gallery/lib/demo/transformations/transformations_demo_gesture_transformable.dart
+++ b/dev/integration_tests/flutter_gallery/lib/demo/transformations/transformations_demo_gesture_transformable.dart
@ -392,9 +392,7 @@ class _GestureTransformableState extends State<GestureTransformable> with Ticker

  // Handle the start of a gesture of _GestureType.
  void _onScaleStart(ScaleStartDetails details) {
-    if (widget.onScaleStart != null) {
-      widget.onScaleStart!(details);
-    }
+    widget.onScaleStart?.call(details);

    if (_controller.isAnimating) {
      _controller.stop();
@ -417,13 +415,11 @@ class _GestureTransformableState extends State<GestureTransformable> with Ticker
  // Handle an update to an ongoing gesture of _GestureType.
  void _onScaleUpdate(ScaleUpdateDetails details) {
    double scale = _transform.getMaxScaleOnAxis();
-    if (widget.onScaleUpdate != null) {
-      widget.onScaleUpdate!(ScaleUpdateDetails(
-        focalPoint: fromViewport(details.focalPoint, _transform),
-        scale: details.scale,
-        rotation: details.rotation,
-      ));
-    }
+    widget.onScaleUpdate?.call(ScaleUpdateDetails(
+      focalPoint: fromViewport(details.focalPoint, _transform),
+      scale: details.scale,
+      rotation: details.rotation,
+    ));
    final Offset focalPointScene = fromViewport(
      details.focalPoint,
      _transform,
@ -476,9 +472,7 @@ class _GestureTransformableState extends State<GestureTransformable> with Ticker

  // Handle the end of a gesture of _GestureType.
  void _onScaleEnd(ScaleEndDetails details) {
-    if (widget.onScaleEnd != null) {
-      widget.onScaleEnd!(details);
-    }
+    widget.onScaleEnd?.call(details);
    setState(() {
      _scaleStart = null;
      _rotationStart = null;
--- a/packages/flutter/lib/src/cupertino/picker.dart
+++ b/packages/flutter/lib/src/cupertino/picker.dart
@ -255,9 +255,7 @@ class _CupertinoPickerState extends State<CupertinoPicker> {
      HapticFeedback.selectionClick();
    }

-    if (widget.onSelectedItemChanged != null) {
-      widget.onSelectedItemChanged!(index);
-    }
+    widget.onSelectedItemChanged?.call(index);
  }

  /// Draws the selectionOverlay.
--- a/packages/flutter/lib/src/cupertino/slider.dart
+++ b/packages/flutter/lib/src/cupertino/slider.dart
@ -475,18 +475,14 @@ class _RenderCupertinoSlider extends RenderConstrainedBox {

  void _startInteraction(Offset globalPosition) {
    if (isInteractive) {
-      if (onChangeStart != null) {
-        onChangeStart!(_discretizedCurrentDragValue);
-      }
+      onChangeStart?.call(_discretizedCurrentDragValue);
      _currentDragValue = _value;
      onChanged!(_discretizedCurrentDragValue);
    }
  }

  void _endInteraction() {
-    if (onChangeEnd != null) {
-      onChangeEnd!(_discretizedCurrentDragValue);
-    }
+    onChangeEnd?.call(_discretizedCurrentDragValue);
    _currentDragValue = 0.0;
  }

--- a/packages/flutter/lib/src/cupertino/text_field.dart
+++ b/packages/flutter/lib/src/cupertino/text_field.dart
@ -116,8 +116,7 @@ class _CupertinoTextFieldSelectionGestureDetectorBuilder extends TextSelectionGe
    }
    super.onSingleTapUp(details);
    _state._requestKeyboard();
-    if (_state.widget.onTap != null)
-      _state.widget.onTap!();
+    _state.widget.onTap?.call();
  }

  @override
--- a/packages/flutter/lib/src/foundation/assertions.dart
+++ b/packages/flutter/lib/src/foundation/assertions.dart
@ -1104,9 +1104,7 @@ class FlutterError extends Error with DiagnosticableTreeMixin implements Asserti
  static void reportError(FlutterErrorDetails details) {
    assert(details != null);
    assert(details.exception != null);
-    if (onError != null) {
-      onError!(details);
-    }
+    onError?.call(details);
  }
 }

--- a/packages/flutter/lib/src/material/bottom_sheet.dart
+++ b/packages/flutter/lib/src/material/bottom_sheet.dart
@ -193,9 +193,7 @@ class _BottomSheetState extends State<BottomSheet> {
  bool get _dismissUnderway => widget.animationController!.status == AnimationStatus.reverse;

  void _handleDragStart(DragStartDetails details) {
-    if (widget.onDragStart != null) {
-      widget.onDragStart!(details);
-    }
+    widget.onDragStart?.call(details);
  }

  void _handleDragUpdate(DragUpdateDetails details) {
@ -226,12 +224,10 @@ class _BottomSheetState extends State<BottomSheet> {
      widget.animationController!.forward();
    }

-    if (widget.onDragEnd != null) {
-      widget.onDragEnd!(
-        details,
-        isClosing: isClosing,
-      );
-    }
+    widget.onDragEnd?.call(
+      details,
+      isClosing: isClosing,
+    );

    if (isClosing) {
      widget.onClosing();
--- a/packages/flutter/lib/src/material/button.dart
+++ b/packages/flutter/lib/src/material/button.dart
@ -330,9 +330,7 @@ class _RawMaterialButtonState extends State<RawMaterialButton> {
    if (_pressed != value) {
      setState(() {
        _updateState(MaterialState.pressed, value);
-        if (widget.onHighlightChanged != null) {
-          widget.onHighlightChanged!(value);
-        }
+        widget.onHighlightChanged?.call(value);
      });
    }
  }
--- a/packages/flutter/lib/src/material/dropdown.dart
+++ b/packages/flutter/lib/src/material/dropdown.dart
@ -150,9 +150,7 @@ class _DropdownMenuItemButtonState<T> extends State<_DropdownMenuItemButton<T>>
  void _handleOnTap() {
    final DropdownMenuItem<T> dropdownMenuItem = widget.route.items[widget.itemIndex].item!;

-    if (dropdownMenuItem.onTap != null) {
-      dropdownMenuItem.onTap!();
-    }
+    dropdownMenuItem.onTap?.call();

    Navigator.pop(
      context,
@ -1270,13 +1268,10 @@ class _DropdownButtonState<T> extends State<DropdownButton<T>> with WidgetsBindi
      _removeDropdownRoute();
      if (!mounted || newValue == null)
        return;
-      if (widget.onChanged != null)
-        widget.onChanged!(newValue.result);
+      widget.onChanged?.call(newValue.result);
    });

-    if (widget.onTap != null) {
-      widget.onTap!();
-    }
+    widget.onTap?.call();
  }

  // When isDense is true, reduce the height of this button from _kMenuItemHeight to
--- a/packages/flutter/lib/src/material/expand_icon.dart
+++ b/packages/flutter/lib/src/material/expand_icon.dart
@ -137,8 +137,7 @@ class _ExpandIconState extends State<ExpandIcon> with SingleTickerProviderStateM
  }

  void _handlePressed() {
-    if (widget.onPressed != null)
-      widget.onPressed!(widget.isExpanded);
+    widget.onPressed?.call(widget.isExpanded);
  }

  /// Default icon colors and opacities for when [Theme.brightness] is set to
--- a/packages/flutter/lib/src/material/expansion_panel.dart
+++ b/packages/flutter/lib/src/material/expansion_panel.dart
@ -442,8 +442,7 @@ class _ExpansionPanelListState extends State<ExpansionPanelList> {
  }

  void _handlePressed(bool isExpanded, int index) {
-    if (widget.expansionCallback != null)
-      widget.expansionCallback!(index, isExpanded);
+    widget.expansionCallback?.call(index, isExpanded);

    if (widget._allowOnlyOnePanelOpen) {
      final ExpansionPanelRadio pressedChild = widget.children[index] as ExpansionPanelRadio;
--- a/packages/flutter/lib/src/material/expansion_tile.dart
+++ b/packages/flutter/lib/src/material/expansion_tile.dart
@ -241,8 +241,7 @@ class _ExpansionTileState extends State<ExpansionTile> with SingleTickerProvider
      }
      PageStorage.of(context)?.writeState(context, _isExpanded);
    });
-    if (widget.onExpansionChanged != null)
-      widget.onExpansionChanged!(_isExpanded);
+    widget.onExpansionChanged?.call(_isExpanded);
  }

  Widget _buildChildren(BuildContext context, Widget? child) {
--- a/packages/flutter/lib/src/material/material.dart
+++ b/packages/flutter/lib/src/material/material.dart
@ -626,8 +626,7 @@ abstract class InkFeature {
      return true;
    }());
    _controller._removeFeature(this);
-    if (onRemoved != null)
-      onRemoved!();
+    onRemoved?.call();
  }

  void _paint(Canvas canvas) {
--- a/packages/flutter/lib/src/material/popup_menu.dart
+++ b/packages/flutter/lib/src/material/popup_menu.dart
@ -1110,12 +1110,10 @@ class PopupMenuButtonState<T> extends State<PopupMenuButton<T>> {
        if (!mounted)
          return null;
        if (newValue == null) {
-          if (widget.onCanceled != null)
-            widget.onCanceled!();
+          widget.onCanceled?.call();
          return null;
        }
-        if (widget.onSelected != null)
-          widget.onSelected!(newValue);
+        widget.onSelected?.call(newValue);
      });
    }
  }
--- a/packages/flutter/lib/src/material/range_slider.dart
+++ b/packages/flutter/lib/src/material/range_slider.dart
@ -1131,9 +1131,7 @@ class _RenderRangeSlider extends RenderBox with RelayoutWhenSystemFontsChangeMix
      }
      _updateLabelPainter(_lastThumbSelection!);

-      if (onChangeStart != null) {
-        onChangeStart!(currentValues);
-      }
+      onChangeStart?.call(currentValues);

      onChanged!(_discretizeRangeValues(_newValues));

@ -1202,9 +1200,7 @@ class _RenderRangeSlider extends RenderBox with RelayoutWhenSystemFontsChangeMix

    if (_active && _state.mounted && _lastThumbSelection != null) {
      final RangeValues discreteValues = _discretizeRangeValues(_newValues);
-      if (onChangeEnd != null) {
-        onChangeEnd!(discreteValues);
-      }
+      onChangeEnd?.call(discreteValues);
      _active = false;
    }
    _state.overlayController.reverse();
@ -1710,12 +1706,8 @@ class _RenderValueIndicator extends RenderBox with RelayoutWhenSystemFontsChange

  @override
  void paint(PaintingContext context, Offset offset) {
-    if (_state.paintBottomValueIndicator != null) {
-      _state.paintBottomValueIndicator!(context, offset);
-    }
-    if (_state.paintTopValueIndicator != null) {
-      _state.paintTopValueIndicator!(context, offset);
-    }
+    _state.paintBottomValueIndicator?.call(context, offset);
+    _state.paintTopValueIndicator?.call(context, offset);
  }

  @override
--- a/packages/flutter/lib/src/material/slider.dart
+++ b/packages/flutter/lib/src/material/slider.dart
@ -1230,9 +1230,7 @@ class _RenderSlider extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
      // We supply the *current* value as the start location, so that if we have
      // a tap, it consists of a call to onChangeStart with the previous value and
      // a call to onChangeEnd with the new value.
-      if (onChangeStart != null) {
-        onChangeStart!(_discretize(value));
-      }
+      onChangeStart?.call(_discretize(value));
      _currentDragValue = _getValueFromGlobalPosition(globalPosition);
      onChanged!(_discretize(_currentDragValue));
      _state.overlayController.forward();
@ -1256,9 +1254,7 @@ class _RenderSlider extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
    }

    if (_active && _state.mounted) {
-      if (onChangeEnd != null) {
-        onChangeEnd!(_discretize(_currentDragValue));
-      }
+      onChangeEnd?.call(_discretize(_currentDragValue));
      _active = false;
      _currentDragValue = 0.0;
      _state.overlayController.reverse();
@ -1584,9 +1580,7 @@ class _RenderValueIndicator extends RenderBox with RelayoutWhenSystemFontsChange

  @override
  void paint(PaintingContext context, Offset offset) {
-    if (_state.paintValueIndicator != null) {
-      _state.paintValueIndicator!(context, offset);
-    }
+    _state.paintValueIndicator?.call(context, offset);
  }

  @override
--- a/packages/flutter/lib/src/material/stepper.dart
+++ b/packages/flutter/lib/src/material/stepper.dart
@ -648,8 +648,7 @@ class _StepperState extends State<Stepper> with TickerProviderStateMixin {
                    duration: kThemeAnimationDuration,
                  );

-                  if (widget.onStepTapped != null)
-                    widget.onStepTapped!(i);
+                  widget.onStepTapped?.call(i);
                } : null,
                canRequestFocus: widget.steps[i].state != StepState.disabled,
                child: _buildVerticalHeader(i),
@ -666,8 +665,7 @@ class _StepperState extends State<Stepper> with TickerProviderStateMixin {
      for (int i = 0; i < widget.steps.length; i += 1) ...<Widget>[
        InkResponse(
          onTap: widget.steps[i].state != StepState.disabled ? () {
-            if (widget.onStepTapped != null)
-              widget.onStepTapped!(i);
+            widget.onStepTapped?.call(i);
          } : null,
          canRequestFocus: widget.steps[i].state != StepState.disabled,
          child: Row(
--- a/packages/flutter/lib/src/material/tabs.dart
+++ b/packages/flutter/lib/src/material/tabs.dart
@ -1123,9 +1123,7 @@ class _TabBarState extends State<TabBar> {
  void _handleTap(int index) {
    assert(index >= 0 && index < widget.tabs.length);
    _controller!.animateTo(index);
-    if (widget.onTap != null) {
-      widget.onTap!(index);
-    }
+    widget.onTap?.call(index);
  }

  Widget _buildStyledTab(Widget child, bool selected, Animation<double> animation) {
--- a/packages/flutter/lib/src/material/text_field.dart
+++ b/packages/flutter/lib/src/material/text_field.dart
@ -114,8 +114,7 @@ class _TextFieldSelectionGestureDetectorBuilder extends TextSelectionGestureDete
      }
    }
    _state._requestKeyboard();
-    if (_state.widget.onTap != null)
-      _state.widget.onTap!();
+    _state.widget.onTap?.call();
  }

  @override
--- a/packages/flutter/lib/src/material/time_picker.dart
+++ b/packages/flutter/lib/src/material/time_picker.dart
@ -1074,9 +1074,7 @@ class _DialState extends State<_Dial> with SingleTickerProviderStateMixin {
    _center = null;
    _animateTo(_getThetaForTime(widget.selectedTime));
    if (widget.mode == _TimePickerMode.hour) {
-      if (widget.onHourSelected != null) {
-        widget.onHourSelected!();
-      }
+      widget.onHourSelected?.call();
    }
  }

@ -1092,9 +1090,7 @@ class _DialState extends State<_Dial> with SingleTickerProviderStateMixin {
      } else {
        _announceToAccessibility(context, localizations.formatDecimal(newTime.hourOfPeriod));
      }
-      if (widget.onHourSelected != null) {
-        widget.onHourSelected!();
-      }
+      widget.onHourSelected?.call();
    } else {
      _announceToAccessibility(context, localizations.formatDecimal(newTime.minute));
    }
--- a/packages/flutter/lib/src/painting/decoration_image.dart
+++ b/packages/flutter/lib/src/painting/decoration_image.dart
@ -534,9 +534,7 @@ void paintImage({
      if (existingSizeInfo == null || existingSizeInfo.displaySizeInBytes < sizeInfo.displaySizeInBytes) {
        _pendingImageSizeInfo[sizeInfo.source!] = sizeInfo;
      }
-      if (debugOnPaintImage != null) {
-        debugOnPaintImage!(sizeInfo);
-      }
+      debugOnPaintImage?.call(sizeInfo);
      SchedulerBinding.instance!.addPostFrameCallback((Duration timeStamp) {
        _lastFrameImageSizeInfo = _pendingImageSizeInfo.values.toSet();
        if (_pendingImageSizeInfo.isEmpty) {
--- a/packages/flutter/lib/src/rendering/editable.dart
+++ b/packages/flutter/lib/src/rendering/editable.dart
@ -598,9 +598,7 @@ class RenderEditable extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
    if (nextSelection == selection && cause != SelectionChangedCause.keyboard && !focusingEmpty) {
      return;
    }
-    if (onSelectionChanged != null) {
-      onSelectionChanged!(nextSelection, this, cause);
-    }
+    onSelectionChanged?.call(nextSelection, this, cause);
  }

  static final Set<LogicalKeyboardKey> _movementKeys = <LogicalKeyboardKey>{
--- a/packages/flutter/lib/src/rendering/proxy_box.dart
+++ b/packages/flutter/lib/src/rendering/proxy_box.dart
@ -4760,103 +4760,83 @@ class RenderSemanticsAnnotations extends RenderProxyBox {
  }

  void _performTap() {
-    if (onTap != null)
-      onTap!();
+    onTap?.call();
  }

  void _performLongPress() {
-    if (onLongPress != null)
-      onLongPress!();
+    onLongPress?.call();
  }

  void _performDismiss() {
-    if (onDismiss != null)
-      onDismiss!();
+    onDismiss?.call();
  }

  void _performScrollLeft() {
-    if (onScrollLeft != null)
-      onScrollLeft!();
+    onScrollLeft?.call();
  }

  void _performScrollRight() {
-    if (onScrollRight != null)
-      onScrollRight!();
+    onScrollRight?.call();
  }

  void _performScrollUp() {
-    if (onScrollUp != null)
-      onScrollUp!();
+    onScrollUp?.call();
  }

  void _performScrollDown() {
-    if (onScrollDown != null)
-      onScrollDown!();
+    onScrollDown?.call();
  }

  void _performIncrease() {
-    if (onIncrease != null)
-      onIncrease!();
+    onIncrease?.call();
  }

  void _performDecrease() {
-    if (onDecrease != null)
-      onDecrease!();
+    onDecrease?.call();
  }

  void _performCopy() {
-    if (onCopy != null)
-      onCopy!();
+    onCopy?.call();
  }

  void _performCut() {
-    if (onCut != null)
-      onCut!();
+    onCut?.call();
  }

  void _performPaste() {
-    if (onPaste != null)
-      onPaste!();
+    onPaste?.call();
  }

  void _performMoveCursorForwardByCharacter(bool extendSelection) {
-    if (onMoveCursorForwardByCharacter != null)
-      onMoveCursorForwardByCharacter!(extendSelection);
+    onMoveCursorForwardByCharacter?.call(extendSelection);
  }

  void _performMoveCursorBackwardByCharacter(bool extendSelection) {
-    if (onMoveCursorBackwardByCharacter != null)
-      onMoveCursorBackwardByCharacter!(extendSelection);
+    onMoveCursorBackwardByCharacter?.call(extendSelection);
  }

  void _performMoveCursorForwardByWord(bool extendSelection) {
-    if (onMoveCursorForwardByWord != null)
-      onMoveCursorForwardByWord!(extendSelection);
+    onMoveCursorForwardByWord?.call(extendSelection);
  }

  void _performMoveCursorBackwardByWord(bool extendSelection) {
-    if (onMoveCursorBackwardByWord != null)
-      onMoveCursorBackwardByWord!(extendSelection);
+    onMoveCursorBackwardByWord?.call(extendSelection);
  }

  void _performSetSelection(TextSelection selection) {
-    if (onSetSelection != null)
-      onSetSelection!(selection);
+    onSetSelection?.call(selection);
  }

  void _performSetText(String text) {
-    if (onSetText != null)
-      onSetText!(text);
+    onSetText?.call(text);
  }

  void _performDidGainAccessibilityFocus() {
-    if (onDidGainAccessibilityFocus != null)
-      onDidGainAccessibilityFocus!();
+    onDidGainAccessibilityFocus?.call();
  }

  void _performDidLoseAccessibilityFocus() {
-    if (onDidLoseAccessibilityFocus != null)
-      onDidLoseAccessibilityFocus!();
+    onDidLoseAccessibilityFocus?.call();
  }
 }

--- a/packages/flutter/lib/src/widgets/basic.dart
+++ b/packages/flutter/lib/src/widgets/basic.dart
@ -6178,8 +6178,7 @@ class WidgetToRenderBoxAdapter extends LeafRenderObjectWidget {

  @override
  void updateRenderObject(BuildContext context, RenderBox renderObject) {
-    if (onBuild != null)
-      onBuild!();
+    onBuild?.call();
  }
 }

--- a/packages/flutter/lib/src/widgets/dismissible.dart
+++ b/packages/flutter/lib/src/widgets/dismissible.dart
@ -543,13 +543,9 @@ class _DismissibleState extends State<Dismissible> with TickerProviderStateMixin

  void _handleResizeProgressChanged() {
    if (_resizeController!.isCompleted) {
-      if (widget.onDismissed != null) {
-        final DismissDirection direction = _dismissDirection;
-        widget.onDismissed!(direction);
-      }
+      widget.onDismissed?.call(_dismissDirection);
    } else {
-      if (widget.onResize != null)
-        widget.onResize!();
+      widget.onResize?.call();
    }
  }

--- a/packages/flutter/lib/src/widgets/drag_target.dart
+++ b/packages/flutter/lib/src/widgets/drag_target.dart
@ -576,8 +576,7 @@ class _DraggableState<T extends Object> extends State<Draggable<T>> {
          widget.onDraggableCanceled!(velocity, offset);
      },
    );
-    if (widget.onDragStarted != null)
-      widget.onDragStarted!();
+    widget.onDragStarted?.call();
    return avatar;
  }

@ -754,8 +753,7 @@ class _DragTargetState<T extends Object> extends State<DragTarget<T>> {
      _candidateAvatars.remove(avatar);
      _rejectedAvatars.remove(avatar);
    });
-    if (widget.onLeave != null)
-      widget.onLeave!(avatar.data as T?);
+    widget.onLeave?.call(avatar.data as T?);
  }

  void didDrop(_DragAvatar<Object> avatar) {
@ -765,17 +763,14 @@ class _DragTargetState<T extends Object> extends State<DragTarget<T>> {
    setState(() {
      _candidateAvatars.remove(avatar);
    });
-    if (widget.onAccept != null)
-      widget.onAccept!(avatar.data! as T);
-    if (widget.onAcceptWithDetails != null)
-      widget.onAcceptWithDetails!(DragTargetDetails<T>(data: avatar.data! as T, offset: avatar._lastOffset!));
+    widget.onAccept?.call(avatar.data! as T);
+    widget.onAcceptWithDetails?.call(DragTargetDetails<T>(data: avatar.data! as T, offset: avatar._lastOffset!));
  }

  void didMove(_DragAvatar<Object> avatar) {
    if (!mounted)
      return;
-    if (widget.onMove != null)
-      widget.onMove!(DragTargetDetails<T>(data: avatar.data! as T, offset: avatar._lastOffset!));
+    widget.onMove?.call(DragTargetDetails<T>(data: avatar.data! as T, offset: avatar._lastOffset!));
  }

  @override
@ -937,8 +932,7 @@ class _DragAvatar<T extends Object> extends Drag {
    _entry!.remove();
    _entry = null;
    // TODO(ianh): consider passing _entry as well so the client can perform an animation.
-    if (onDragEnd != null)
-      onDragEnd!(velocity ?? Velocity.zero, _lastOffset!, wasAccepted);
+    onDragEnd?.call(velocity ?? Velocity.zero, _lastOffset!, wasAccepted);
  }

  Widget _build(BuildContext context) {
--- a/packages/flutter/lib/src/widgets/focus_scope.dart
+++ b/packages/flutter/lib/src/widgets/focus_scope.dart
@ -670,9 +670,7 @@ class _FocusState extends State<Focus> {
    final bool hasPrimaryFocus = focusNode.hasPrimaryFocus;
    final bool canRequestFocus = focusNode.canRequestFocus;
    final bool descendantsAreFocusable = focusNode.descendantsAreFocusable;
-    if (widget.onFocusChange != null) {
-      widget.onFocusChange!(focusNode.hasFocus);
-    }
+    widget.onFocusChange?.call(focusNode.hasFocus);
    if (_hasPrimaryFocus != hasPrimaryFocus) {
      setState(() {
        _hasPrimaryFocus = hasPrimaryFocus;
--- a/packages/flutter/lib/src/widgets/form.dart
+++ b/packages/flutter/lib/src/widgets/form.dart
@ -167,9 +167,7 @@ class FormState extends State<Form> {
  // Called when a form field has changed. This will cause all form fields
  // to rebuild, useful if form fields have interdependencies.
  void _fieldDidChange() {
-    if (widget.onChanged != null)
-      widget.onChanged!();
-
+    widget.onChanged?.call();

    _hasInteractedByUser = _fields
        .any((FormFieldState<dynamic> field) => field._hasInteractedByUser);
@ -435,8 +433,7 @@ class FormFieldState<T> extends State<FormField<T>> {

  /// Calls the [FormField]'s onSaved method with the current value.
  void save() {
-    if (widget.onSaved != null)
-      widget.onSaved!(value);
+    widget.onSaved?.call(value);
  }

  /// Resets the field to its initial value.
--- a/packages/flutter/lib/src/widgets/framework.dart
+++ b/packages/flutter/lib/src/widgets/framework.dart
@ -4241,9 +4241,7 @@ abstract class Element extends DiagnosticableTree implements BuildContext {
    if (_lifecycleState != _ElementLifecycle.active || !_dirty)
      return;
    assert(() {
-      if (debugOnRebuildDirtyWidget != null) {
-        debugOnRebuildDirtyWidget!(this, _debugBuiltOnce);
-      }
+      debugOnRebuildDirtyWidget?.call(this, _debugBuiltOnce);
      if (debugPrintRebuildDirtyWidgets) {
        if (!_debugBuiltOnce) {
          debugPrint('Building $this');
--- a/packages/flutter/lib/src/widgets/gesture_detector.dart
+++ b/packages/flutter/lib/src/widgets/gesture_detector.dart
@ -1332,12 +1332,9 @@ class _DefaultSemanticsGestureDelegate extends SemanticsGestureDelegate {

    return () {
      assert(tap != null);
-      if (tap.onTapDown != null)
-        tap.onTapDown!(TapDownDetails());
-      if (tap.onTapUp != null)
-        tap.onTapUp!(TapUpDetails(kind: PointerDeviceKind.unknown));
-      if (tap.onTap != null)
-        tap.onTap!();
+      tap.onTapDown?.call(TapDownDetails());
+      tap.onTapUp?.call(TapUpDetails(kind: PointerDeviceKind.unknown));
+      tap.onTap?.call();
    };
  }

@ -1347,14 +1344,10 @@ class _DefaultSemanticsGestureDelegate extends SemanticsGestureDelegate {
      return null;

    return () {
-      if (longPress.onLongPressStart != null)
-        longPress.onLongPressStart!(const LongPressStartDetails());
-      if (longPress.onLongPress != null)
-        longPress.onLongPress!();
-      if (longPress.onLongPressEnd != null)
-        longPress.onLongPressEnd!(const LongPressEndDetails());
-      if (longPress.onLongPressUp != null)
-        longPress.onLongPressUp!();
+      longPress.onLongPressStart?.call(const LongPressStartDetails());
+      longPress.onLongPress?.call();
+      longPress.onLongPressEnd?.call(const LongPressEndDetails());
+      longPress.onLongPressUp?.call();
    };
  }

@ -1365,27 +1358,19 @@ class _DefaultSemanticsGestureDelegate extends SemanticsGestureDelegate {
    final GestureDragUpdateCallback? horizontalHandler = horizontal == null ?
      null :
      (DragUpdateDetails details) {
-        if (horizontal.onDown != null)
-          horizontal.onDown!(DragDownDetails());
-        if (horizontal.onStart != null)
-          horizontal.onStart!(DragStartDetails());
-        if (horizontal.onUpdate != null)
-          horizontal.onUpdate!(details);
-        if (horizontal.onEnd != null)
-          horizontal.onEnd!(DragEndDetails(primaryVelocity: 0.0));
+        horizontal.onDown?.call(DragDownDetails());
+        horizontal.onStart?.call(DragStartDetails());
+        horizontal.onUpdate?.call(details);
+        horizontal.onEnd?.call(DragEndDetails(primaryVelocity: 0.0));
      };

    final GestureDragUpdateCallback? panHandler = pan == null ?
      null :
      (DragUpdateDetails details) {
-        if (pan.onDown != null)
-          pan.onDown!(DragDownDetails());
-        if (pan.onStart != null)
-          pan.onStart!(DragStartDetails());
-        if (pan.onUpdate != null)
-          pan.onUpdate!(details);
-        if (pan.onEnd != null)
-          pan.onEnd!(DragEndDetails());
+        pan.onDown?.call(DragDownDetails());
+        pan.onStart?.call(DragStartDetails());
+        pan.onUpdate?.call(details);
+        pan.onEnd?.call(DragEndDetails());
      };

    if (horizontalHandler == null && panHandler == null)
@ -1405,27 +1390,19 @@ class _DefaultSemanticsGestureDelegate extends SemanticsGestureDelegate {
    final GestureDragUpdateCallback? verticalHandler = vertical == null ?
      null :
      (DragUpdateDetails details) {
-        if (vertical.onDown != null)
-          vertical.onDown!(DragDownDetails());
-        if (vertical.onStart != null)
-          vertical.onStart!(DragStartDetails());
-        if (vertical.onUpdate != null)
-          vertical.onUpdate!(details);
-        if (vertical.onEnd != null)
-          vertical.onEnd!(DragEndDetails(primaryVelocity: 0.0));
+        vertical.onDown?.call(DragDownDetails());
+        vertical.onStart?.call(DragStartDetails());
+        vertical.onUpdate?.call(details);
+        vertical.onEnd?.call(DragEndDetails(primaryVelocity: 0.0));
      };

    final GestureDragUpdateCallback? panHandler = pan == null ?
      null :
      (DragUpdateDetails details) {
-        if (pan.onDown != null)
-          pan.onDown!(DragDownDetails());
-        if (pan.onStart != null)
-          pan.onStart!(DragStartDetails());
-        if (pan.onUpdate != null)
-          pan.onUpdate!(details);
-        if (pan.onEnd != null)
-          pan.onEnd!(DragEndDetails());
+        pan.onDown?.call(DragDownDetails());
+        pan.onStart?.call(DragStartDetails());
+        pan.onUpdate?.call(details);
+        pan.onEnd?.call(DragEndDetails());
      };

    if (verticalHandler == null && panHandler == null)
--- a/packages/flutter/lib/src/widgets/implicit_animations.dart
+++ b/packages/flutter/lib/src/widgets/implicit_animations.dart
@ -370,8 +370,7 @@ abstract class ImplicitlyAnimatedWidgetState<T extends ImplicitlyAnimatedWidget>
    _controller.addStatusListener((AnimationStatus status) {
      switch (status) {
        case AnimationStatus.completed:
-          if (widget.onEnd != null)
-            widget.onEnd!();
+          widget.onEnd?.call();
          break;
        case AnimationStatus.dismissed:
        case AnimationStatus.forward:
--- a/packages/flutter/lib/src/widgets/modal_barrier.dart
+++ b/packages/flutter/lib/src/widgets/modal_barrier.dart
@ -228,8 +228,7 @@ class _AnyTapGestureRecognizer extends BaseTapGestureRecognizer {
  @protected
  @override
  void handleTapUp({PointerDownEvent? down, PointerUpEvent? up}) {
-    if (onAnyTapUp != null)
-      onAnyTapUp!();
+    onAnyTapUp?.call();
  }

  @protected
--- a/packages/flutter/lib/src/widgets/navigator.dart
+++ b/packages/flutter/lib/src/widgets/navigator.dart
@ -5968,9 +5968,7 @@ class RestorableRouteFuture<T> extends RestorableProperty<String?> {
      _route?.restorationScopeId.removeListener(notifyListeners);
      _route = null;
      notifyListeners();
-      if (onComplete != null) {
-        onComplete!(result as T);
-      }
+      onComplete?.call(result as T);
    });
  }

--- a/packages/flutter/lib/src/widgets/platform_view.dart
+++ b/packages/flutter/lib/src/widgets/platform_view.dart
@ -638,9 +638,7 @@ class _UiKitViewState extends State<UiKitView> {
      controller.dispose();
      return;
    }
-    if (widget.onPlatformViewCreated != null) {
-      widget.onPlatformViewCreated!(id);
-    }
+    widget.onPlatformViewCreated?.call(id);
    setState(() { _controller = controller; });
  }
 }
--- a/packages/flutter/lib/src/widgets/raw_keyboard_listener.dart
+++ b/packages/flutter/lib/src/widgets/raw_keyboard_listener.dart
@ -121,8 +121,7 @@ class _RawKeyboardListenerState extends State<RawKeyboardListener> {
  }

  void _handleRawKeyEvent(RawKeyEvent event) {
-    if (widget.onKey != null)
-      widget.onKey!(event);
+    widget.onKey?.call(event);
  }

  @override
--- a/packages/flutter/lib/src/widgets/routes.dart
+++ b/packages/flutter/lib/src/widgets/routes.dart
@ -445,8 +445,7 @@ class LocalHistoryEntry {
  }

  void _notifyRemoved() {
-    if (onRemove != null)
-      onRemove!();
+    onRemove?.call();
  }
 }

--- a/packages/flutter/lib/src/widgets/scroll_activity.dart
+++ b/packages/flutter/lib/src/widgets/scroll_activity.dart
@ -214,8 +214,7 @@ class HoldScrollActivity extends ScrollActivity implements ScrollHoldController

  @override
  void dispose() {
-    if (onHoldCanceled != null)
-      onHoldCanceled!();
+    onHoldCanceled?.call();
    super.dispose();
  }
 }
@ -406,8 +405,7 @@ class ScrollDragController implements Drag {
  @mustCallSuper
  void dispose() {
    _lastDetails = null;
-    if (onDragCanceled != null)
-      onDragCanceled!();
+    onDragCanceled?.call();
  }

  /// The most recently observed [DragStartDetails], [DragUpdateDetails], or
--- a/packages/flutter/lib/src/widgets/text_selection.dart
+++ b/packages/flutter/lib/src/widgets/text_selection.dart
@ -782,8 +782,7 @@ class _TextSelectionHandleOverlayState
  }

  void _handleTap() {
-    if (widget.onSelectionHandleTapped != null)
-      widget.onSelectionHandleTapped!();
+    widget.onSelectionHandleTapped?.call();
  }

  @override
@ -1386,9 +1385,7 @@ class _TextSelectionGestureDetectorState extends State<TextSelectionGestureDetec
  // The down handler is force-run on success of a single tap and optimistically
  // run before a long press success.
  void _handleTapDown(TapDownDetails details) {
-    if (widget.onTapDown != null) {
-      widget.onTapDown!(details);
-    }
+    widget.onTapDown?.call(details);
    // This isn't detected as a double tap gesture in the gesture recognizer
    // because it's 2 single taps, each of which may do different things depending
    // on whether it's a single tap, the first tap of a double tap, the second
@ -1396,9 +1393,7 @@ class _TextSelectionGestureDetectorState extends State<TextSelectionGestureDetec
    if (_doubleTapTimer != null && _isWithinDoubleTapTolerance(details.globalPosition)) {
      // If there was already a previous tap, the second down hold/tap is a
      // double tap down.
-      if (widget.onDoubleTapDown != null) {
-        widget.onDoubleTapDown!(details);
-      }
+      widget.onDoubleTapDown?.call(details);

      _doubleTapTimer!.cancel();
      _doubleTapTimeout();
@ -1408,9 +1403,7 @@ class _TextSelectionGestureDetectorState extends State<TextSelectionGestureDetec

  void _handleTapUp(TapUpDetails details) {
    if (!_isDoubleTap) {
-      if (widget.onSingleTapUp != null) {
-        widget.onSingleTapUp!(details);
-      }
+      widget.onSingleTapUp?.call(details);
      _lastTapOffset = details.globalPosition;
      _doubleTapTimer = Timer(kDoubleTapTimeout, _doubleTapTimeout);
    }
@ -1418,9 +1411,7 @@ class _TextSelectionGestureDetectorState extends State<TextSelectionGestureDetec
  }

  void _handleTapCancel() {
-    if (widget.onSingleTapCancel != null) {
-      widget.onSingleTapCancel!();
-    }
+    widget.onSingleTapCancel?.call();
  }

  DragStartDetails? _lastDragStartDetails;
@ -1430,9 +1421,7 @@ class _TextSelectionGestureDetectorState extends State<TextSelectionGestureDetec
  void _handleDragStart(DragStartDetails details) {
    assert(_lastDragStartDetails == null);
    _lastDragStartDetails = details;
-    if (widget.onDragSelectionStart != null) {
-      widget.onDragSelectionStart!(details);
-    }
+    widget.onDragSelectionStart?.call(details);
  }

  void _handleDragUpdate(DragUpdateDetails details) {
@ -1450,9 +1439,7 @@ class _TextSelectionGestureDetectorState extends State<TextSelectionGestureDetec
  void _handleDragUpdateThrottled() {
    assert(_lastDragStartDetails != null);
    assert(_lastDragUpdateDetails != null);
-    if (widget.onDragSelectionUpdate != null) {
-      widget.onDragSelectionUpdate!(_lastDragStartDetails!, _lastDragUpdateDetails!);
-    }
+    widget.onDragSelectionUpdate?.call(_lastDragStartDetails!, _lastDragUpdateDetails!);
    _dragUpdateThrottleTimer = null;
    _lastDragUpdateDetails = null;
  }
@ -1465,9 +1452,7 @@ class _TextSelectionGestureDetectorState extends State<TextSelectionGestureDetec
      _dragUpdateThrottleTimer!.cancel();
      _handleDragUpdateThrottled();
    }
-    if (widget.onDragSelectionEnd != null) {
-      widget.onDragSelectionEnd!(details);
-    }
+    widget.onDragSelectionEnd?.call(details);
    _dragUpdateThrottleTimer = null;
    _lastDragStartDetails = null;
    _lastDragUpdateDetails = null;
@ -1476,13 +1461,11 @@ class _TextSelectionGestureDetectorState extends State<TextSelectionGestureDetec
  void _forcePressStarted(ForcePressDetails details) {
    _doubleTapTimer?.cancel();
    _doubleTapTimer = null;
-    if (widget.onForcePressStart != null)
-      widget.onForcePressStart!(details);
+    widget.onForcePressStart?.call(details);
  }

  void _forcePressEnded(ForcePressDetails details) {
-    if (widget.onForcePressEnd != null)
-      widget.onForcePressEnd!(details);
+    widget.onForcePressEnd?.call(details);
  }

  void _handleLongPressStart(LongPressStartDetails details) {
--- a/packages/flutter/test/gestures/team_test.dart
+++ b/packages/flutter/test/gestures/team_test.dart
@ -130,9 +130,7 @@ class PassiveGestureRecognizer extends OneSequenceGestureRecognizer {

  @override
  void acceptGesture(int pointer) {
-    if (onGestureAccepted != null) {
-      onGestureAccepted!();
-    }
+    onGestureAccepted?.call();
  }

  @override
--- a/packages/flutter/test/rendering/mouse_tracker_test_utils.dart
+++ b/packages/flutter/test/rendering/mouse_tracker_test_utils.dart
@ -89,8 +89,7 @@ class TestAnnotationTarget with Diagnosticable implements MouseTrackerAnnotation
  @override
  void handleEvent(PointerEvent event, HitTestEntry entry) {
    if (event is PointerHoverEvent)
-      if (onHover != null)
-        onHover!(event);
+      onHover?.call(event);
  }
 }

--- a/packages/flutter/test/widgets/image_filter_quality_test.dart
+++ b/packages/flutter/test/widgets/image_filter_quality_test.dart
@ -111,9 +111,7 @@ class _TestImageStreamCompleter extends ImageStreamCompleter {
  }) {
    final List<ImageStreamListener> localListeners = listeners.toList();
    for (final ImageStreamListener listener in localListeners) {
-      if (listener.onError != null) {
-        listener.onError!(exception, stackTrace);
-      }
+      listener.onError?.call(exception, stackTrace);
    }
  }
 }
--- a/packages/flutter/test/widgets/image_test.dart
+++ b/packages/flutter/test/widgets/image_test.dart
@ -2026,9 +2026,7 @@ class _TestImageStreamCompleter extends ImageStreamCompleter {
  }) {
    final List<ImageStreamListener> localListeners = listeners.toList();
    for (final ImageStreamListener listener in localListeners) {
-      if (listener.onError != null) {
-        listener.onError!(exception, stackTrace);
-      }
+      listener.onError?.call(exception, stackTrace);
    }
  }
 }
--- a/packages/flutter/test/widgets/independent_widget_layout_test.dart
+++ b/packages/flutter/test/widgets/independent_widget_layout_test.dart
@ -86,8 +86,7 @@ class Counter {
 class Trigger {
  VoidCallback? callback;
  void fire() {
-    if (callback != null)
-      callback!();
+    callback?.call();
  }
 }

--- a/packages/flutter/test/widgets/mouse_region_test.dart
+++ b/packages/flutter/test/widgets/mouse_region_test.dart
@ -29,21 +29,13 @@ class HoverClient extends StatefulWidget {

 class HoverClientState extends State<HoverClient> {
  void _onExit(PointerExitEvent details) {
-    if (widget.onExit != null) {
-      widget.onExit!();
-    }
-    if (widget.onHover != null) {
-      widget.onHover!(false);
-    }
+    widget.onExit?.call();
+    widget.onHover?.call(false);
  }

  void _onEnter(PointerEnterEvent details) {
-    if (widget.onEnter != null) {
-      widget.onEnter!();
-    }
-    if (widget.onHover != null) {
-      widget.onHover!(true);
-    }
+    widget.onEnter?.call();
+    widget.onHover?.call(true);
  }

  @override
--- a/packages/flutter/test/widgets/navigator_test.dart
+++ b/packages/flutter/test/widgets/navigator_test.dart
@ -3587,22 +3587,19 @@ class RouteAnnouncementSpy extends Route<void> {
  @override
  void didChangeNext(Route<dynamic>? nextRoute) {
    super.didChangeNext(nextRoute);
-    if (onDidChangeNext != null)
-      onDidChangeNext!(nextRoute);
+    onDidChangeNext?.call(nextRoute);
  }

  @override
  void didChangePrevious(Route<dynamic>? previousRoute) {
    super.didChangePrevious(previousRoute);
-    if (onDidChangePrevious != null)
-      onDidChangePrevious!(previousRoute);
+    onDidChangePrevious?.call(previousRoute);
  }

  @override
  void didPopNext(Route<dynamic> nextRoute) {
    super.didPopNext(nextRoute);
-    if (onDidPopNext != null)
-      onDidPopNext!(nextRoute);
+    onDidPopNext?.call(nextRoute);
  }
 }

@ -3728,9 +3725,7 @@ class HeroControllerSpy extends HeroController {
  OnObservation? onPushed;
  @override
  void didPush(Route<dynamic>? route, Route<dynamic>? previousRoute) {
-    if (onPushed != null) {
-      onPushed!(route, previousRoute);
-    }
+    onPushed?.call(route, previousRoute);
  }
 }

--- a/packages/flutter/test/widgets/observer_tester.dart
+++ b/packages/flutter/test/widgets/observer_tester.dart
@ -16,33 +16,26 @@ class TestObserver extends NavigatorObserver {

  @override
  void didPush(Route<dynamic> route, Route<dynamic>? previousRoute) {
-    if (onPushed != null) {
-      onPushed!(route, previousRoute);
-    }
+    onPushed?.call(route, previousRoute);
  }

  @override
  void didPop(Route<dynamic> route, Route<dynamic>? previousRoute) {
-    if (onPopped != null) {
-      onPopped!(route, previousRoute);
-    }
+    onPopped?.call(route, previousRoute);
  }

  @override
  void didRemove(Route<dynamic> route, Route<dynamic>? previousRoute) {
-    if (onRemoved != null)
-      onRemoved!(route, previousRoute);
+    onRemoved?.call(route, previousRoute);
  }

  @override
  void didReplace({ Route<dynamic>? oldRoute, Route<dynamic>? newRoute }) {
-    if (onReplaced != null)
-      onReplaced!(newRoute, oldRoute);
+    onReplaced?.call(newRoute, oldRoute);
  }

  @override
  void didStartUserGesture(Route<dynamic> route, Route<dynamic>? previousRoute) {
-    if (onStartUserGesture != null)
-      onStartUserGesture!(route, previousRoute);
+    onStartUserGesture?.call(route, previousRoute);
  }
 }
--- a/packages/flutter_test/lib/src/test_text_input.dart
+++ b/packages/flutter_test/lib/src/test_text_input.dart
@ -102,8 +102,7 @@ class TestTextInput {
      case 'TextInput.clearClient':
        _client = 0;
        _isVisible = false;
-        if (onCleared != null)
-          onCleared!();
+        onCleared?.call();
        break;
      case 'TextInput.setEditingState':
        editingState = methodCall.arguments as Map<String, dynamic>;