title: Accessibility on custom UISlider
body: <p>I have created a custom range UISlider with two thumb. However in VoiceOver mode, I am not able to swipe up and down to adjust the thumb.</p>
  
  <pre><code>UIAccessibilityElement *minElement = [[UIAccessibilityElement alloc] initWithAccessibilityContainer:self];
  minElement.accessibilityFrame = [self convertRect:currentThumbRect
                                               toView:nil];
  minElement.accessibilityLabel = NSLocalizedString(@"Minimum", nil);
  minElement.accessibilityTraits = UIAccessibilityTraitAdjustable;
  
  [_accessibleElements addObject:minElement];
  
  UIAccessibilityElement *maxElement = [[UIAccessibilityElement alloc]
                                         initWithAccessibilityContainer:self];
  maxElement.accessibilityFrame = [self convertRect:currentUpperThumbRect
                                              toView:nil];
  maxElement.accessibilityLabel = NSLocalizedString(@"Maximum", nil);
  maxElement.accessibilityTraits = UIAccessibilityTraitAdjustable;
  
  [_accessibleElements addObject:maxElement]
  </code></pre>
  
  <p>I have added code above so that VoiceOver can recognize both thumb separately, but I couldn't adjust the thumb. Any idea to make the thumb adjustable in VoiceOver.</p>
  
  <hr>
  
  <p><strong>Problem Solved:</strong></p>
  
  <p>I use 'UIAccessibilityCustomAction' to add in custom behavior. Instead of slide up and down to adjust the value, in custom behavior slide up and down can be use to choose the action and double tap to perform it.</p>
  
  <pre><code>UIAccessibilityElement *minElement = [[UIAccessibilityElement alloc] initWithAccessibilityContainer:self];
  minElement.accessibilityLabel = NSLocalizedString(@"Minimum", nil);
  UIAccessibilityCustomAction *increaseMinAction = [[UIAccessibilityCustomAction alloc] initWithName:NSLocalizedString(@"Increase minimum", @"action to increase min")
                                                                                                   target:self selector:@selector(accessibilityMinIncrement)];
  UIAccessibilityCustomAction *decreaseMinAction = [[UIAccessibilityCustomAction alloc] initWithName:NSLocalizedString(@"Decrease minimum", @"action to decrease min")
                                                                                                   target:self selector:@selector(accessibilityMinDecrement)];
  minElement.accessibilityCustomActions = @[increaseMinAction, decreaseMinAction];
  [_accessibleElements addObject:minElement];
  </code></pre>