我想消除我的NSAttributedString开头和结尾处的空格(修剪它)。我不能简单地将其转换为字符串并进行修剪,因为其中包含图像(附件)。我该怎么做?
NSAttributedString
扩展。extension NSAttributedString {
public func attributedStringByTrimmingCharacterSet(charSet: CharacterSet) -> NSAttributedString {
let modifiedString = NSMutableAttributedString(attributedString: self)
modifiedString.trimCharactersInSet(charSet: charSet)
return NSAttributedString(attributedString: modifiedString)
}
}
extension NSMutableAttributedString {
public func trimCharactersInSet(charSet: CharacterSet) {
var range = (string as NSString).rangeOfCharacter(from: charSet as CharacterSet)
// Trim leading characters from character set.
while range.length != 0 && range.location == 0 {
replaceCharacters(in: range, with: "")
range = (string as NSString).rangeOfCharacter(from: charSet)
}
// Trim trailing characters from character set.
range = (string as NSString).rangeOfCharacter(from: charSet, options: .backwards)
while range.length != 0 && NSMaxRange(range) == length {
replaceCharacters(in: range, with: "")
range = (string as NSString).rangeOfCharacter(from: charSet, options: .backwards)
}
}
}
并在您希望使用的视图控制器中使用。例如:
let attstring = NSAttributedString(string: "this is test message. Please wait. ")
let result = attstring.attributedStringByTrimmingCharacterSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
这在文本中甚至适用于表情符号
extension NSAttributedString {
/** Will Trim space and new line from start and end of the text */
public func trimWhiteSpace() -> NSAttributedString {
let invertedSet = CharacterSet.whitespacesAndNewlines.inverted
let startRange = string.utf16.description.rangeOfCharacter(from: invertedSet)
let endRange = string.utf16.description.rangeOfCharacter(from: invertedSet, options: .backwards)
guard let startLocation = startRange?.upperBound, let endLocation = endRange?.lowerBound else {
return NSAttributedString(string: string)
}
let location = string.utf16.distance(from: string.startIndex, to: startLocation) - 1
let length = string.utf16.distance(from: startLocation, to: endLocation) + 2
let range = NSRange(location: location, length: length)
return attributedSubstring(from: range)
}
}
使用方法
let attributeString = NSAttributedString(string: "\n\n\n Hi buddy. ")
let result = attributeString.trimWhiteSpace().string // Hi buddy.
发现Unicode字符串很难哈哈哈!这里发布的其他解决方案是一个很好的起点,但在使用非拉丁字符时,它们对我产生了崩溃。
无论何时在Swift字符串中使用索引或范围,我们都需要使用String.Index
而不是普通的Int
。从Range<String.Index>
创建NSRange
必须使用NSRange(swiftRange, in: String)
。
话虽如此,该代码基于其他答案进行了构建,但使其支持Unicode:
public extension NSMutableAttributedString {
/// Trims new lines and whitespaces off the beginning and the end of attributed strings
func trimmedAttributedString() -> NSAttributedString {
let invertedSet = CharacterSet.whitespacesAndNewlines.inverted
let startRange = string.rangeOfCharacter(from: invertedSet)
let endRange = string.rangeOfCharacter(from: invertedSet, options: .backwards)
guard let startLocation = startRange?.lowerBound, let endLocation = endRange?.lowerBound else {
return NSAttributedString(string: string)
}
let trimmedRange = startLocation...endLocation
return attributedSubstring(from: NSRange(trimmedRange, in: string))
}
}
Swift 4及以上版本
extension NSMutableAttributedString {
func trimmedAttributedString() -> NSAttributedString {
let invertedSet = CharacterSet.whitespacesAndNewlines.inverted
let startRange = string.rangeOfCharacter(from: invertedSet)
let endRange = string.rangeOfCharacter(from: invertedSet, options: .backwards)
guard let startLocation = startRange?.upperBound, let endLocation = endRange?.lowerBound else {
return NSAttributedString(string: string)
}
let location = string.distance(from: string.startIndex, to: startLocation) - 1
let length = string.distance(from: startLocation, to: endLocation) + 2
let range = NSRange(location: location, length: length)
return attributedSubstring(from: range)
}
}
用途:
let string = "This is string with some space in the end. "
let attributedText = NSMutableAttributedString(string: string).trimmedAttributedString()
我做了一个Swift 3实现,以防有人感兴趣:
/**
Trim an attributed string. Can for example be used to remove all leading and trailing spaces and line breaks.
*/
public func attributedStringByTrimmingCharactersInSet(set: CharacterSet) -> NSAttributedString {
let invertedSet = set.inverted
let rangeFromStart = string.rangeOfCharacter(from: invertedSet)
let rangeFromEnd = string.rangeOfCharacter(from: invertedSet, options: .backwards)
if let startLocation = rangeFromStart?.upperBound, let endLocation = rangeFromEnd?.lowerBound {
let location = string.distance(from: string.startIndex, to: startLocation) - 1
let length = string.distance(from: startLocation, to: endLocation) + 2
let newRange = NSRange(location: location, length: length)
return self.attributedSubstring(from: newRange)
} else {
return NSAttributedString()
}
}
Swift 3.2 版本:
extension NSAttributedString {
public func trimmingCharacters(in characterSet: CharacterSet) -> NSAttributedString {
let modifiedString = NSMutableAttributedString(attributedString: self)
modifiedString.trimCharacters(in: characterSet)
return NSAttributedString(attributedString: modifiedString)
}
}
extension NSMutableAttributedString {
public func trimCharacters(in characterSet: CharacterSet) {
var range = (string as NSString).rangeOfCharacter(from: characterSet)
// Trim leading characters from character set.
while range.length != 0 && range.location == 0 {
replaceCharacters(in: range, with: "")
range = (string as NSString).rangeOfCharacter(from: characterSet)
}
// Trim trailing characters from character set.
range = (string as NSString).rangeOfCharacter(from: characterSet, options: .backwards)
while range.length != 0 && NSMaxRange(range) == length {
replaceCharacters(in: range, with: "")
range = (string as NSString).rangeOfCharacter(from: characterSet, options: .backwards)
}
}
}
以下代码将适用于您的要求。
var attString: NSAttributedString = NSAttributedString(string: " this is att string")
let trimmedString = attString.string.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet())
String
而不是 NSAttributedString
。你只需要将 String
转换成 NSAttributedString
就可以了。只需要两行漂亮的代码。 - Bhautik Ziniya