I have created ReadMoreLabel class to add at the end of given line. I have few issues currently as we have 2 different language to manage (English and Japanese).
- Sometimes it’s hard to tap on Japanese language
- If we have next line character after just one character,
...ReadMoreis not attached to label.
Here is the code for the same.
public final class ReadMoreLabel: UILabel {
override public var text: String? {
willSet(newValue) {
self.originalText = newValue
}
}
private var originalText:String?
private var trailingText = "read_more".localized
var didTapReadMore: (() -> Void)?
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
private func addTapGesture() {
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(handleTap(tap:)))
self.addGestureRecognizer(tapGesture)
self.isUserInteractionEnabled = true
}
public func addTrailingText(
trailingText: String = "...",
textToAppend: String,
fontOfTextToAppend: UIFont,
colorOfTextToAppend: UIColor
) {
let readMoreText = trailingText + textToAppend
// dont do anything if its frame is not set
guard self.frame != CGRect.zero, self.text?.isEmpty == false else{
return
}
self.trailingText = textToAppend
self.originalText = self.text
let errorPadding = 4
// first get the string that can be displayed in the required number of lines
guard self.numberOfLines != 0,
let lengthForVisibleString = self.visibleTextLength(),
let unwrappedText = self.text, (lengthForVisibleString < unwrappedText.count),
(lengthForVisibleString < unwrappedText.count), unwrappedText.count > (readMoreText.utf16.count + errorPadding)
else {
return
}
var startIndex = unwrappedText.index(unwrappedText.startIndex, offsetBy: lengthForVisibleString)
var range = startIndex..<unwrappedText.endIndex
// string without read more text that can be displayed
let strTrimmedWithoutReadMore = unwrappedText.replacingCharacters(in: range, with: "")
var startIndexOffset = strTrimmedWithoutReadMore.count - readMoreText.utf16.count - errorPadding
if startIndexOffset < 0 {
startIndexOffset = 0
}
startIndex = unwrappedText.index(unwrappedText.startIndex, offsetBy: startIndexOffset)
let endIndex = unwrappedText.index(startIndex, offsetBy: readMoreText.utf16.count + errorPadding)
range = startIndex..<endIndex
var strTrimmedWithReadMode = strTrimmedWithoutReadMore
// Check if the range is within the bounds of the string
if startIndex >= strTrimmedWithoutReadMore.startIndex && endIndex <= strTrimmedWithoutReadMore.endIndex {
strTrimmedWithReadMode = strTrimmedWithoutReadMore.replacingCharacters(in: range, with: "") + "..."
} else {
strTrimmedWithReadMode += "..."
}
let answerAttributed = NSMutableAttributedString(string: strTrimmedWithReadMode, attributes: [.font: self.font ?? UIFont.font(type: .regular, size: 12)])
// string with characters trimmed for read more string
let attributes: [NSAttributedString.Key: Any] = [
.font: self.font ?? UIFont.font(type: .regular, size: 12),
.underlineStyle: NSUnderlineStyle.single.rawValue
]
// add read more attribtuted string
let readMoreAttributed = NSMutableAttributedString(string: textToAppend, attributes: attributes)
answerAttributed.append(readMoreAttributed)
self.attributedText = answerAttributed
addTapGesture()
}
@objc func handleTap(tap: UITapGestureRecognizer) {
guard let unwrappedText = self.text, let range = unwrappedText.range(of: self.trailingText) else{
return
}
let nsRange = NSRange(location: range.lowerBound.utf16Offset(in: unwrappedText), length: range.upperBound.utf16Offset(in: unwrappedText) - range.lowerBound.utf16Offset(in: unwrappedText))
guard self.didTapAttributedText(locationFromTapGesture: tap.location(in: self), range: nsRange) else{
return
}
self.text = originalText
self.didTapReadMore?()
}
// returns the last index of the string that can be added
private func visibleTextLength() -> Int? {
guard let unwrappedText = self.text, let unwrappedFont = self.font, unwrappedText.isEmpty == false else {
return nil
}
let lineBreakMode = NSLineBreakMode.byTruncatingTail
let width = self.frame.size.width
// Determine the target size as in how much can fit
let size = CGSize(width: width, height: CGFloat.greatestFiniteMagnitude)
let attributes: [NSAttributedString.Key: Any] = [NSAttributedString.Key.font: unwrappedFont]
let attributedText = NSAttributedString(string: unwrappedText, attributes: attributes)
let boundingRect = attributedText.boundingRect(with: size, options: .usesLineFragmentOrigin, context: nil)
// Compute the number of lines based on the target size
let totalNumberOfLines = Int(ceil(boundingRect.height / font.lineHeight))
guard totalNumberOfLines > self.numberOfLines else {
return unwrappedText.utf16.count
}
var index = unwrappedText.unicodeScalars.startIndex
var prev = unwrappedText.unicodeScalars.startIndex
_ = CharacterSet.whitespacesAndNewlines
let endIndex = unwrappedText.unicodeScalars.endIndex
// Iterate through the string and for each word check if it can be added to the required size of the string or not
repeat {
prev = index
let unwrappedIndex = index
let startIndex = unwrappedText.unicodeScalars.index(after: unwrappedIndex)
_ = startIndex..<unwrappedText.unicodeScalars.endIndex
if lineBreakMode == NSLineBreakMode.byCharWrapping {
index = unwrappedText.index(after: unwrappedIndex)
} else {
index = unwrappedText.unicodeScalars.index(after: unwrappedIndex)
}
} while (isHeightGreaterThanLabelHeight(indexOne: index, indexTwo: endIndex, text: unwrappedText, targetSize: size, attributes: attributes))
return prev.utf16Offset(in: unwrappedText)
}
private func isHeightGreaterThanLabelHeight(indexOne: String.Index?, indexTwo: String.Index?, text: String, targetSize: CGSize, attributes: [NSAttributedString.Key: Any]) -> Bool {
guard let unwrappedIndexOne = indexOne, let unwrappedIndexTwo = indexTwo else {
return false
}
guard unwrappedIndexOne.utf16Offset(in: text) < unwrappedIndexTwo.utf16Offset(in: text) else {
return false
}
let substring = String(text[...unwrappedIndexOne])
let boundingRect = substring.boundingRect(with: targetSize, options: .usesLineFragmentOrigin, attributes: attributes, context: nil)
let totalNumberOfLines = Int(ceil(boundingRect.size.height / font.lineHeight))
return totalNumberOfLines <= self.numberOfLines
}
private func didTapAttributedText(locationFromTapGesture: CGPoint, range: NSRange) -> Bool {
guard let attributedText = self.attributedText else {
return false
}
let layoutManager = NSLayoutManager()
let textContainer = NSTextContainer(size: CGSize(width: bounds.width, height: .greatestFiniteMagnitude))
let textStorage = NSTextStorage(attributedString: attributedText)
layoutManager.addTextContainer(textContainer)
textStorage.addLayoutManager(layoutManager)
textContainer.lineFragmentPadding = 0
textContainer.lineBreakMode = .byWordWrapping
textContainer.maximumNumberOfLines = numberOfLines
let numberOfGlyphs = layoutManager.numberOfGlyphs
var glyphRange = NSRange()
for index in 0..<numberOfGlyphs {
layoutManager.lineFragmentRect(forGlyphAt: index, effectiveRange: &glyphRange)
let characterRange = layoutManager.characterRange(forGlyphRange: glyphRange, actualGlyphRange: nil)
if NSIntersectionRange(characterRange, range).length > 0 {
let location = layoutManager.location(forGlyphAt: index)
let boundingRect = layoutManager.boundingRect(forGlyphRange: glyphRange, in: textContainer)
let adjustedRect = boundingRect.offsetBy(dx: 0, dy: location.y-8)
if adjustedRect.contains(locationFromTapGesture) {
return true
}
}
}
return false
}
}
Can someone help me to find out the issue or have a better solution for it?
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