FlutterSemanticsScrollView.mm

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// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#import "flutter/shell/platform/darwin/ios/framework/Source/FlutterSemanticsScrollView.h"
 
#import "flutter/shell/platform/darwin/common/framework/Headers/FlutterMacros.h"
#import "flutter/shell/platform/darwin/ios/framework/Source/SemanticsObject.h"
 
FLUTTER_ASSERT_ARC
 
@implementation FlutterSemanticsScrollView
 
- (instancetype)initWithSemanticsObject:(SemanticsObject*)semanticsObject {
  self = [super initWithFrame:CGRectZero];
  if (self) {
    _semanticsObject = semanticsObject;
    _isDoingSystemScrolling = NO;
    self.delegate = self;
  }
  return self;
}
 
- (UIView*)hitTest:(CGPoint)point withEvent:(UIEvent*)event {
  return nil;
}
 
// The following methods are explicitly forwarded to the wrapped SemanticsObject because the
// forwarding logic above doesn't apply to them since they are also implemented in the
// UIScrollView class, the base class.
 
- (BOOL)isAccessibilityElement {
  if (![self.semanticsObject isAccessibilityBridgeAlive]) {
    return NO;
  }
 
  if (self.semanticsObject.isAccessibilityElement) {
    return YES;
  }
  if (self.contentSize.width > self.frame.size.width ||
      self.contentSize.height > self.frame.size.height) {
    // In SwitchControl or VoiceControl, the isAccessibilityElement must return YES
    // in order to use scroll actions.
    return ![self.semanticsObject bridge]->isVoiceOverRunning();
  } else {
    return NO;
  }
}
 
- (NSString*)accessibilityLabel {
  return self.semanticsObject.accessibilityLabel;
}
 
- (NSAttributedString*)accessibilityAttributedLabel {
  return self.semanticsObject.accessibilityAttributedLabel;
}
 
- (NSString*)accessibilityValue {
  return self.semanticsObject.accessibilityValue;
}
 
- (NSAttributedString*)accessibilityAttributedValue {
  return self.semanticsObject.accessibilityAttributedValue;
}
 
- (NSString*)accessibilityHint {
  return self.semanticsObject.accessibilityHint;
}
 
- (NSAttributedString*)accessibilityAttributedHint {
  return self.semanticsObject.accessibilityAttributedHint;
}
 
- (BOOL)accessibilityActivate {
  return [self.semanticsObject accessibilityActivate];
}
 
- (void)accessibilityIncrement {
  [self.semanticsObject accessibilityIncrement];
}
 
- (void)accessibilityDecrement {
  [self.semanticsObject accessibilityDecrement];
}
 
- (BOOL)accessibilityScroll:(UIAccessibilityScrollDirection)direction {
  return [self.semanticsObject accessibilityScroll:direction];
}
 
- (BOOL)accessibilityPerformEscape {
  return [self.semanticsObject accessibilityPerformEscape];
}
 
- (void)accessibilityElementDidBecomeFocused {
  [self.semanticsObject accessibilityElementDidBecomeFocused];
}
 
- (void)accessibilityElementDidLoseFocus {
  [self.semanticsObject accessibilityElementDidLoseFocus];
}
 
- (id)accessibilityContainer {
  return self.semanticsObject.accessibilityContainer;
}
 
- (NSInteger)accessibilityElementCount {
  return self.semanticsObject.children.count;
}
 
- (void)scrollViewWillEndDragging:(UIScrollView*)scrollView
                     withVelocity:(CGPoint)velocity
              targetContentOffset:(inout CGPoint*)targetContentOffset {
  _isDoingSystemScrolling = YES;
}
 
- (void)scrollViewDidEndDecelerating:(UIScrollView*)scrollView {
  _isDoingSystemScrolling = NO;
}
 
@end