SOLVED: Passing .formatted(...) to a View

@0xifarouk

May '23

I am trying to pass a .formatted(...) to a view, something like this:

NumberPreviewer(1000, minimizedStyle: .number, maximizedStyle: .percent)

But it's not compiling and I am getting the following error: No exact matches in call to instance method 'formatted' No exact matches in call to instance method 'appendInterpolation'

Here is the code for NumberPreviewer:

struct NumberPreviewer<S>: View where S: FormatStyle {

  private let number: Double?
  @State private var state: PreviewState
  private let minimizedStyle: S
  private let maximizedStyle: S

  init(
    _ number: Double,
    state: PreviewState = .minimized,
    minimizedStyle: S,
    maximizedStyle: S
  ) {
    self.number = number
    self._state = State(wrappedValue: state)
    self.minimizedStyle = minimizedStyle
    self.maximizedStyle = maximizedStyle
  }

  var body: some View {
    if let number {
        switch state {
          case .maximized:
            Text("\(number.formatted(maximizedStyle))") // error is here
          case .minimized:
            Text("\(number.formatted(minimizedStyle))") // error is here
        }
    } else {
      Text("-")
    }
  }

  enum PreviewState {
    case maximized
    case minimized

    mutating func toggle() {
      switch self {
        case .maximized:
          self = .minimized
        case .minimized:
          self = .maximized
      }
    }
  }
}

@Hectorcrdna

May '23

Hi,

You need to explicitly state the FormatOutput equal to String also you need 2 generics since S can't be .number and .percent at the same time.

struct NumberPreviewer<S, T>: View where S : FormatStyle, T : FormatStyle, S.FormatInput == Double, T.FormatInput == Double, S.FormatOutput == String, T.FormatOutput == String {

    private let number: Double?
    @State private var state: PreviewState
    private let minimizedStyle: S
    private let maximizedStyle: T

      init(
        _ number: Double,
        state: PreviewState = .minimized,
        minimizedStyle: S,
        maximizedStyle: T
      ) {
        self.number = number
        self._state = State(wrappedValue: state)
        self.minimizedStyle = minimizedStyle
        self.maximizedStyle = maximizedStyle
      }

          var body: some View {
              if let number {
                      switch state {
                        case .maximized:
                          Text("\(maximizedStyle.format(number))")
                        case .minimized:
                          Text("\(minimizedStyle.format(number))")
                      }
                  } else {
                    Text("-")
                  }
          }

            enum PreviewState {
                case maximized
                case minimized

            mutating func toggle() {
            switch self {
                case .maximized:
                  self = .minimized
                case .minimized:
                  self = .maximized
            }
        }
    }
}

@0xifarouk

May '23

Thanks a lot.

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