Repo created

iphone/Maps/UI/PlacePage/Views/ExpandableLabel.swift

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+final class ExpandableLabel: UIView {
+  typealias OnExpandClosure = (() -> Void) -> Void
+
+  private let stackView = UIStackView()
+  private let textView = UITextView()
+  private let expandLabel = UILabel()
+
+  var onExpandClosure: OnExpandClosure?
+
+  var font = UIFont.systemFont(ofSize: 16) {
+    didSet {
+      textView.font = font
+      expandLabel.font = font
+    }
+  }
+
+  var textColor = UIColor.black {
+    didSet {
+      textView.textColor = textColor
+    }
+  }
+
+  var expandColor = UIColor.systemBlue {
+    didSet {
+      expandLabel.textColor = expandColor
+    }
+  }
+
+  var text: String? {
+    didSet {
+      containerText = text
+      textView.text = text
+      if let text = text {
+        isHidden = text.isEmpty
+      } else {
+        isHidden = true
+      }
+    }
+  }
+
+  var attributedText: NSAttributedString? {
+    didSet {
+      containerText = attributedText?.string
+      textView.attributedText = attributedText
+      if let attributedText = attributedText {
+        isHidden = attributedText.length == 0
+      } else {
+        isHidden = true
+      }
+    }
+  }
+
+  var expandText = "More" {
+    didSet {
+      expandLabel.text = expandText
+    }
+  }
+
+  var numberOfLines = 2 {
+    didSet {
+      containerMaximumNumberOfLines = numberOfLines > 0 ? numberOfLines + 1 : 0
+    }
+  }
+
+  private var containerText: String?
+  private var containerMaximumNumberOfLines = 2 {
+    didSet {
+      textView.textContainer.maximumNumberOfLines = containerMaximumNumberOfLines
+      textView.invalidateIntrinsicContentSize()
+    }
+  }
+
+  private var oldWidth: CGFloat = 0
+
+  override func setContentHuggingPriority(_ priority: UILayoutPriority, for axis: NSLayoutConstraint.Axis) {
+    super.setContentHuggingPriority(priority, for: axis)
+    textView.setContentHuggingPriority(priority, for: axis)
+    expandLabel.setContentHuggingPriority(priority, for: axis)
+  }
+
+  override init(frame: CGRect) {
+    super.init(frame: frame)
+    commonInit()
+  }
+
+  required init?(coder: NSCoder) {
+    super.init(coder: coder)
+    commonInit()
+  }
+
+  private func commonInit() {
+    stackView.axis = .vertical
+    stackView.alignment = .leading
+    containerMaximumNumberOfLines = numberOfLines > 0 ? numberOfLines + 1 : 0
+    textView.textContainer.lineFragmentPadding = 0
+    textView.isScrollEnabled = false
+    textView.isEditable = false
+    textView.textContainerInset = .zero
+    textView.contentMode = .topLeft
+    textView.font = font
+    textView.textColor = textColor
+    textView.text = text
+    textView.attributedText = attributedText
+    textView.setContentHuggingPriority(contentHuggingPriority(for: .vertical), for: .vertical)
+    textView.backgroundColor = .clear
+    textView.dataDetectorTypes = [.link, .phoneNumber]
+    expandLabel.setContentHuggingPriority(contentHuggingPriority(for: .vertical), for: .vertical)
+    expandLabel.font = font
+    expandLabel.textColor = expandColor
+    expandLabel.text = expandText
+    expandLabel.isHidden = true
+    addSubview(stackView)
+
+    stackView.addArrangedSubview(textView)
+    stackView.addArrangedSubview(expandLabel)
+    stackView.alignToSuperview()
+    let gr = UITapGestureRecognizer(target: self, action: #selector(onExpand(_:)))
+    addGestureRecognizer(gr)
+  }
+
+  @objc func onExpand(_ sender: UITapGestureRecognizer) {
+    if expandLabel.isHidden { return }
+
+    let expandClosure = {
+      UIView.animate(withDuration: kDefaultAnimationDuration) {
+        self.containerMaximumNumberOfLines = 0
+        self.expandLabel.isHidden = true
+        self.stackView.layoutIfNeeded()
+      }
+    }
+    if let onExpandClosure = onExpandClosure {
+      onExpandClosure(expandClosure)
+    } else {
+      expandClosure()
+    }
+  }
+
+  override func layoutSubviews() {
+    super.layoutSubviews()
+
+    if oldWidth != bounds.width, let attributedText = attributedText?.mutableCopy() as? NSMutableAttributedString {
+      attributedText.enumerateAttachments(estimatedWidth: bounds.width)
+      self.attributedText = attributedText
+      oldWidth = bounds.width
+    }
+    
+    guard containerMaximumNumberOfLines > 0,
+      containerMaximumNumberOfLines != numberOfLines,
+      let s = containerText,
+      !s.isEmpty else {
+        return
+    }
+    let textRect = s.boundingRect(with: CGSize(width: width, height: CGFloat.greatestFiniteMagnitude),
+                                  options: .usesLineFragmentOrigin,
+                                  attributes: [.font: font],
+                                  context: nil)
+    let lineHeight = font.lineHeight
+    if Int(lineHeight * CGFloat(numberOfLines + 1)) >= Int(textRect.height) {
+      expandLabel.isHidden = true
+      containerMaximumNumberOfLines = 0
+    } else {
+      expandLabel.isHidden = false
+      containerMaximumNumberOfLines = numberOfLines
+    }
+    layoutIfNeeded()
+  }
+}