代码之家 › 专栏 › 技术社区 › Raunak

从timeZoneOffset字符串创建时区对象?

timezone-offset swift

0

Raunak · 技术社区 · 5 年前

什么是一个干净的方式来初始化Swift TimeZone 来自timeZoneOffset字符串的对象,格式为:“+HH:MM”。

我在找这样的东西:

extension TimeZone {

    init?(UTCOffsetString ofs: String) {

        let signIndex = ofs.firstIndex(of: "+") ?? ofs.firstIndex(of: "-")
        let sign = ofs[signIndex!]

        let separatorIndex = ofs.firstIndex(of: ":")!

        let hhRange = ofs.index(signIndex!, offsetBy: 1)..<separatorIndex
        let hh = ofs[hhRange]

        let mmRange = ofs.index(separatorIndex, offsetBy: 1)..<ofs.index(separatorIndex, offsetBy: 3)
        let mm = ofs[mmRange]

        var offsetInMin = (Int(String(hh))! * 60) + Int(String(mm))!
        if sign == "-" {
            offsetInMin.negate()
        }

        let offsetInSec = offsetInMin * 60
        // Convert string to TimeZone, eg.
        self.init(secondsFromGMT: offsetInSec)
    }

}

let tz = TimeZone.init(UTCOffsetString: "-07:30")
print(tz?.identifier ?? "unknown")

格林尼治标准时间-0730

0 回复 | 直到 5 年前

1

2

vadian 5 年前

我的建议是使用 DateFormatter 它能够解析时区字符串格式。 refZoneString

extension TimeZone {

    init?(UTCOffsetString ofs: String) {
        let refZoneString = "+0000"
        let formatter = DateFormatter()
        formatter.dateFormat = "Z"
        guard let refDate = formatter.date(from: refZoneString),
            let date = formatter.date(from: ofs) else { return nil }
        self.init(secondsFromGMT: Calendar.current.dateComponents([.second], from: date, to: refDate).second!)
    }
}

let tz = TimeZone.init(UTCOffsetString: "-07:30")
print(tz?.identifier ?? "unknown")

2

0

Leo Dabus 5 年前

我不知道你说的清洁剂是什么意思,但你可以结合收集方法 suffix prefix 要避免使用字符串索引访问所需值,请执行以下操作:

let time = "-02:00"
let hours = Int(time.suffix(5).prefix(2)) ?? 0
let minutes = Int(time.suffix(2)) ?? 0

var offset = hours * 3600 + minutes * 60   
if time.first == "-" { offset = -offset }

print(offset)  // -7200