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Stick the offset when height changes #81

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Merged
merged 3 commits into from
Oct 14, 2018
Merged

Stick the offset when height changes #81

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53a5723
Stick the offset when height changes
Sep 22, 2018
7fe09e8
suppress kvo when changing frame
Sep 22, 2018
791d282
Merge branch 'master' into offset-stick
rnystrom Oct 14, 2018
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2 changes: 2 additions & 0 deletions MessageViewController/MessageAutocompleteController.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -80,6 +80,8 @@ public final class MessageAutocompleteController: MessageTextViewListener {
name: .UIKeyboardWillChangeFrame,
object: nil
)

preserveTypingAttributes(for: textView)
}

// MARK: Public API
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6 changes: 5 additions & 1 deletion MessageViewController/MessageView.swift
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Expand Up @@ -22,6 +22,7 @@ public final class MessageView: UIView, MessageTextViewListener {
internal var leftButtonInset: CGFloat = 0
internal var rightButtonInset: CGFloat = 0
internal var ignoreLineHeight = false
internal var suppressKVO = false

public enum ButtonPosition {
case left
Expand Down Expand Up @@ -308,7 +309,10 @@ public final class MessageView: UIView, MessageTextViewListener {
width: safeBounds.width - leftButtonMaxX - rightButtonSize.width - rightButtonInset,
height: textViewHeight
)

suppressKVO = true
textView.frame = textViewFrame
suppressKVO = false

// adjust by bottom offset so content is flush w/ text view
let rightButtonFrame = CGRect(
Expand All @@ -328,7 +332,7 @@ public final class MessageView: UIView, MessageTextViewListener {
}

public override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
if keyPath == UITextViewContentSizeKeyPath {
if suppressKVO == false, keyPath == UITextViewContentSizeKeyPath {
textViewContentSizeDidChange()
}
}
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2 changes: 1 addition & 1 deletion MessageViewController/MessageViewController+MessageViewDelegate.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,7 @@ extension MessageViewController: MessageViewDelegate {

internal func sizeDidChange(messageView: MessageView) {
UIView.animate(withDuration: 0.25) {
self.layout()
self.layout(updateOffset: true)
}
}

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12 changes: 11 additions & 1 deletion MessageViewController/MessageViewController.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -106,7 +106,7 @@ open class MessageViewController: UIViewController, MessageAutocompleteControlle
}
}

internal func layout() {
internal func layout(updateOffset: Bool = false) {
guard let scrollView = self.scrollView else { return }

let bounds = view.bounds
Expand All @@ -126,6 +126,9 @@ open class MessageViewController: UIViewController, MessageAutocompleteControlle
// required for the nested UITextView to layout its internals correctly
messageView.layoutIfNeeded()

let originalOffset = scrollView.contentOffset
let heightChange = scrollView.frame.height - messageViewFrame.minY

let frame = scrollView.frame
scrollView.frame = CGRect(
x: frame.minX,
Expand All @@ -134,6 +137,13 @@ open class MessageViewController: UIViewController, MessageAutocompleteControlle
height: messageViewFrame.minY - frame.minY
)

if updateOffset, heightChange != 0 {
scrollView.contentOffset = CGPoint(
x: originalOffset.x,
y: max(originalOffset.y + heightChange, -scrollView.util_adjustedContentInset.top)
)
}

messageAutocompleteController.layout(in: view, bottomY: messageViewFrame.minY)

didLayout()
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