我希望我的UILabel以下列方式显示文本6.022 * 1023。迅速对下标和上标有什么影响?
大多数答案+示例都在ObjC中,但这是如何在Swift中完成的。
let font:UIFont? = UIFont(name: "Helvetica", size:20)
let fontSuper:UIFont? = UIFont(name: "Helvetica", size:10)
let attString:NSMutableAttributedString = NSMutableAttributedString(string: "6.022*1023", attributes: [.font:font!])
attString.setAttributes([.font:fontSuper!,.baselineOffset:10], range: NSRange(location:8,length:2))
labelVarName.attributedText = attString
这给了我:
在更详细的解释中:
UIFont
,上标必须更小。NSMutableAttributedString
。NSRange
为要更改的字符(UIFont
)添加属性,NSBaselineOffsetAttributeName
值是您想要垂直偏移它的量。UILabel
希望这也有助于其他Swift开发者,因为我也需要它。
我创建了一个AmountFormatter类,它帮助我将十进制数转换为带小数字的数字。
class AmountFormatter {
static func sharedFormatter(
decimalNumber: NSDecimalNumber,
currency: String,
raisedDecimals: Bool) -> NSAttributedString {
let numberFormatter = NumberFormatter()
numberFormatter.usesGroupingSeparator = true
numberFormatter.groupingSeparator = "."
numberFormatter.decimalSeparator = ","
numberFormatter.numberStyle = .decimal
let scale: Int16 = 2
let behavior = NSDecimalNumberHandler(
roundingMode: .plain,
scale: scale,
raiseOnExactness: false,
raiseOnOverflow: false,
raiseOnUnderflow: false,
raiseOnDivideByZero: true)
guard let amountString = numberFormatter.string(
from: decimalNumber.rounding(accordingToBehavior: behavior))
else {
fatalError("Can't convert conversion from 'NSDecimalNumber' to string")
}
let currencyAmountString = currency + amountString
let font = UIFont(name: "Roboto", size: 20)
let fontSuper = UIFont(name: "Roboto", size: 10)
let attributedCurrencyAmountString = NSMutableAttributedString(
string: currencyAmountString,
attributes: [.font: font!])
if raisedDecimals == false {
return attributedCurrencyAmountString as NSAttributedString
}
var array = attributedCurrencyAmountString.string.split(separator: ",")
let lenght = array[0].count
attributedCurrencyAmountString.setAttributes(
[.font: fontSuper!, .baselineOffset: 10],
range: NSRange(location: lenght, length: 3))
attributedCurrencyAmountString.setAttributes(
[.font: fontSuper!],
range: NSRange(location: 0, length: 1))
return attributedCurrencyAmountString as NSAttributedString
}
}
作为一种不同的方法,我写了一个函数,它接受一个字符串,其中指数前面加上^
,如2^2•3•5^2
并返回2²•3•5²
func exponentize(str: String) -> String {
let supers = [
"1": "\u{00B9}",
"2": "\u{00B2}",
"3": "\u{00B3}",
"4": "\u{2074}",
"5": "\u{2075}",
"6": "\u{2076}",
"7": "\u{2077}",
"8": "\u{2078}",
"9": "\u{2079}"]
var newStr = ""
var isExp = false
for (_, char) in str.characters.enumerate() {
if char == "^" {
isExp = true
} else {
if isExp {
let key = String(char)
if supers.keys.contains(key) {
newStr.append(Character(supers[key]!))
} else {
isExp = false
newStr.append(char)
}
} else {
newStr.append(char)
}
}
}
return newStr
}
这是一种蛮力方法,但是如果您不想处理属性字符串或者希望字符串独立于字体,它就可以工作。
我写了以下扩展名,或者你可以将它作为一个函数使用,它对我来说效果很好。您可以通过跳过对您来说不重要的部分来修改它
extension NSMutableAttributedString
{
enum scripting : Int
{
case aSub = -1
case aSuper = 1
}
func characterSubscriptAndSuperscript(string:String,
characters:[Character],
type:scripting,
fontSize:CGFloat,
scriptFontSize:CGFloat,
offSet:Int,
length:[Int],
alignment:NSTextAlignment)-> NSMutableAttributedString
{
let paraghraphStyle = NSMutableParagraphStyle()
// Set The Paragraph aligmnet , you can ignore this part and delet off the function
paraghraphStyle.alignment = alignment
var scriptedCharaterLocation = Int()
//Define the fonts you want to use and sizes
let stringFont = UIFont.boldSystemFont(ofSize: fontSize)
let scriptFont = UIFont.boldSystemFont(ofSize: scriptFontSize)
// Define Attributes of the text body , this part can be removed of the function
let attString = NSMutableAttributedString(string:string, attributes: [NSFontAttributeName:stringFont,NSForegroundColorAttributeName:UIColor.black,NSParagraphStyleAttributeName: paraghraphStyle])
// the enum is used here declaring the required offset
let baseLineOffset = offSet * type.rawValue
// enumerated the main text characters using a for loop
for (i,c) in string.characters.enumerated()
{
// enumerated the array of first characters to subscript
for (theLength,aCharacter) in characters.enumerated()
{
if c == aCharacter
{
// Get to location of the first character
scriptedCharaterLocation = i
//Now set attributes starting from the character above
attString.setAttributes([NSFontAttributeName:scriptFont,
// baseline off set from . the enum i.e. +/- 1
NSBaselineOffsetAttributeName:baseLineOffset,
NSForegroundColorAttributeName:UIColor.black],
// the range from above location
range:NSRange(location:scriptedCharaterLocation,
// you define the length in the length array
// if subscripting at different location
// you need to define the length for each one
length:length[theLength]))
}
}
}
return attString}
}
例子:
let attStr1 = NSMutableAttributedString().characterSubscriptAndSuperscript(
string: "23 x 456",
characters:["3","5"],
type: .aSuper,
fontSize: 20,
scriptFontSize: 15,
offSet: 10,
length: [1,2],
alignment: .left)
let attStr2 = NSMutableAttributedString().characterSubscriptAndSuperscript(
string: "H2SO4",
characters: ["2","4"],
type: .aSub,
fontSize: 20,
scriptFontSize: 15,
offSet: 8,
length: [1,1],
alignment: .left)
如果你可以使用看起来不完美的文本,并且只需要一个字符子集就可以使用unicode上标和下标数字:⁰¹³⁴⁵⁶⁷⁸⁹₂₂₂₃₄₄₅₅₅₅₅₅₅₅⁹⁹⁹₂ ₇₇₈这样做的好处是不那么累赘。
对于简单易用的Swift解决方案,您可能需要签出HandyUIKit。将其导入项目后(例如通过Carthage - 参见README中的说明),您可以执行以下操作:
import HandyUIKit
"6.022*10^{23}".superscripted(font: UIFont.systemFont(ofSize: 20, weight: .medium))
这一行将返回一个NSAttributedString
,它看起来就像你正在寻找的那样。只需将它分配给UILabel
s attributedText
财产就可以了!
如果您正在寻找订阅文本,只需使用subscripted(font:)
。它将识别像CO_{2}
这样的结构。如果你想要两者结合,还有superAndSubscripted(font:)
。
有关更多信息和其他示例,请参阅docs。
import UIKit
extension NSMutableAttributedString {
enum Scripting : Int {
case aSub = -1
case aSuper = 1
}
func scripts(string: String,
characters: [Character],
type: Scripting,
stringFont: UIFont,
fontSize: CGFloat,
scriptFont: UIFont,
scriptFontSize: CGFloat,
offSet: Int,
length: [Int],
alignment: NSTextAlignment) -> NSMutableAttributedString {
let paraghraphStyle = NSMutableParagraphStyle()
paraghraphStyle.alignment = alignment
var scriptedCharaterLocation = Int()
let attributes = [
NSAttributedStringKey.font: stringFont,
NSAttributedStringKey.foregroundColor: UIColor.black,
NSAttributedStringKey.paragraphStyle: paraghraphStyle
]
let attString = NSMutableAttributedString(string:string, attributes: attributes)
let baseLineOffset = offSet * type.rawValue
let scriptTextAttributes: [NSAttributedStringKey : Any] = [
NSAttributedStringKey.font: scriptFont,
NSAttributedStringKey.baselineOffset: baseLineOffset,
NSAttributedStringKey.foregroundColor: UIColor.blue
]
for (i,c) in string.enumerated() {
for (theLength, aCharacter) in characters.enumerated() {
if c == aCharacter {
scriptedCharaterLocation = i
attString.setAttributes(scriptTextAttributes, range: NSRange(location:scriptedCharaterLocation,
length: length[theLength]))
}
}
}
return attString
}
}
这是一个简单的版本,具有正确的错误处理,将在操场上编译。
import UIKit
func setMyLabelText(myLabel: UILabel) {
if let largeFont = UIFont(name: "Helvetica", size: 20), let superScriptFont = UIFont(name: "Helvetica", size:10) {
let numberString = NSMutableAttributedString(string: "6.022*10", attributes: [.font: largeFont])
numberString.append(NSAttributedString(string: "23", attributes: [.font: superScriptFont, .baselineOffset: 10]))
myLabel.attributedText = numberString
}
}
let myLabel = UILabel()
setMyLabelText(myLabel: myLabel)
一个很好的简单函数,输出一个数字作为上标文本。
func exponent(i: Int) -> String {
let powers : [String] = [
"\u{2070}",
"\u{00B9}",
"\u{00B2}",
"\u{00B3}",
"\u{2074}",
"\u{2075}",
"\u{2076}",
"\u{2077}",
"\u{2078}",
"\u{2079}"
]
let digits = Array(String(i))
var string = ""
for d in digits {
string.append("\(powers[Int(String(d))!])")
}
return string
}
我创建了一个String扩展,它接受一个字符串并将其所有上标转换为unicode字符。这样你就可以毫无困难地共享结果字符串。
extension Character {
var unicode: String {
// See table here: https://en.wikipedia.org/wiki/Unicode_subscripts_and_superscripts
let unicodeChars = [Character("0"):"\u{2070}",
Character("1"):"\u{00B9}",
Character("2"):"\u{00B2}",
Character("3"):"\u{00B3}",
Character("4"):"\u{2074}",
Character("5"):"\u{2075}",
Character("6"):"\u{2076}",
Character("7"):"\u{2077}",
Character("8"):"\u{2078}",
Character("9"):"\u{2079}",
Character("i"):"\u{2071}",
Character("+"):"\u{207A}",
Character("-"):"\u{207B}",
Character("="):"\u{207C}",
Character("("):"\u{207D}",
Character(")"):"\u{207E}",
Character("n"):"\u{207F}"]
if let unicode = unicodeChars[self] {
return unicode
}
return String(self)
}
}
extension String {
var unicodeSuperscript: String {
let char = Character(self)
return char.unicode
}
func superscripted() -> String {
let regex = try! NSRegularExpression(pattern: "\\^\\{([^\\}]*)\\}")
var unprocessedString = self
var resultString = String()
while let match = regex.firstMatch(in: unprocessedString, options: .reportCompletion, range: NSRange(location: 0, length: unprocessedString.count)) {
// add substring before match
let substringRange = unprocessedString.index(unprocessedString.startIndex, offsetBy: match.range.location)
let subString = unprocessedString.prefix(upTo: substringRange)
resultString.append(String(subString))
// add match with subscripted style
let capturedSubstring = NSAttributedString(string: unprocessedString).attributedSubstring(from: match.range(at: 1)).mutableCopy() as! NSMutableAttributedString
capturedSubstring.string.forEach { (char) in
let superScript = char.unicode
let string = NSAttributedString(string: superScript)
resultString.append(string.string)
}
// strip off the processed part
unprocessedString.deleteCharactersInRange(range: NSRange(location: 0, length: match.range.location + match.range.length))
}
// add substring after last match
resultString.append(unprocessedString)
return resultString
}
mutating func deleteCharactersInRange(range: NSRange) {
let mutableSelf = NSMutableString(string: self)
mutableSelf.deleteCharacters(in: range)
self = mutableSelf as String
}
}
例如,"x^{4+n}+12^{3}".superscripted()
生产"x⁴⁺ⁿ+12³"
这是受到HandyUIKit的启发,我的代码的要点是Github