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Fix refresh control positioning #123

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merged 3 commits into from
May 30, 2023
Merged

Fix refresh control positioning #123

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3847dcb
Install refresh control by assigning it to the web view's scroll view.
svara May 16, 2023
a9c19d7
Explicitly add refresh control as subview of scroll view, and use con…
svara May 17, 2023
264ba08
Document refresh control height.
svara May 19, 2023
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11 changes: 11 additions & 0 deletions Source/Visitable/VisitableView.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,7 @@ open class VisitableView: UIView {

open lazy var refreshControl: UIRefreshControl = {
let refreshControl = UIRefreshControl()
refreshControl.translatesAutoresizingMaskIntoConstraints = false
refreshControl.addTarget(self, action: #selector(refresh(_:)), for: .valueChanged)
return refreshControl
}()
Expand All @@ -68,6 +69,16 @@ open class VisitableView: UIView {

#if !targetEnvironment(macCatalyst)
scrollView.addSubview(refreshControl)

/// Infer refresh control's default height from its frame, if given.
/// Otherwise fallback to 60 (the default height).
let refreshControlHeight = refreshControl.frame.height > 0 ? refreshControl.frame.height : 60

Comment on lines +72 to +76
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Why do we have to specify the height?
Internally, refresh control doesn't use autolayout for positioning its subviews. Its main frame doesn't reflect its true size. The main container height is 60pt, but the view where the refresh image/animation is has a height of 100pt. When using autolayout the latter is used. 🤷‍♂️ Even if we don't set the height, the refresh control will respect the safe area, but it won't be positioned as it should be.

Screenshot 2023-05-17 at 11 52 53

NSLayoutConstraint.activate([
refreshControl.centerXAnchor.constraint(equalTo: centerXAnchor),
refreshControl.topAnchor.constraint(equalTo: safeAreaLayoutGuide.topAnchor),
refreshControl.heightAnchor.constraint(equalToConstant: refreshControlHeight)
])
Comment on lines +77 to +81
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Using autolayout ensures the system takes care of updating the view's position as appropriate.
centerXAnchor makes sure the control is always centered with the view’s horizontal center.
Pinning control's top anchor to the view's safe area top anchor ensures the control is positioned within the safe area.

#endif
}

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