NumericTextField

A SwiftUI text field for decimal numbers that validates every keystroke. Input is limited to digits and the locale's decimal separator, with configurable integer and fraction digit limits. The value is bound as Decimal, so there are no floating-point rounding errors.

@State private var price: Decimal?

NumericTextField(value: $price, maxIntegerDigits: 6, maxFractionDigits: 2)

Features

• Validates per keystroke: only digits and one decimal separator, within the digit limits
• Locale-aware: 1.234,5 in German, 1,234.5 in English. A typed . or , always counts as the decimal separator, so the field works with any keyboard region.
• Binds to Decimal? or Decimal
• Shows grouping separators while not editing and plain digits while editing
• Rounds half up (0.125 → 0.13)
• Follows .multilineTextAlignment (including right-to-left) and .disabled
• Styling modifiers for font, text color and the keyboard dismiss button
• Optional focus binding

Requirements

• iOS 17+
• Swift 6 / Xcode 16+

On other platforms the package compiles, but the view is not available.

Installation

In Xcode, choose File → Add Package Dependencies… and enter the repository URL. In Package.swift:

dependencies: [
    .package(url: "https://github.com/dirkfabisch/NumericTextField.git", from: "0.1.0")
]

Usage

Optional and non-optional values

@State private var amount: Decimal?   // cleared field → nil
@State private var quantity: Decimal = 1 // cleared field → 0

NumericTextField(value: $amount, placeholder: "0.00")
NumericTextField(value: $quantity, maxIntegerDigits: 4, maxFractionDigits: 0)

With maxFractionDigits: 0 the field shows a number pad without a separator key.

Locale

The field uses Locale.autoupdatingCurrent by default. Pass a locale to fix the format:

NumericTextField(value: $amount, locale: Locale(identifier: "de_DE"))

Alignment and styling

Form {
    NumericTextField(value: $net)
    NumericTextField(value: $gross)
}
.multilineTextAlignment(.trailing)
.numericTextFieldFont(.monospacedDigitSystemFont(ofSize: 17, weight: .regular))
.numericTextFieldColor(.blue)
.numericTextFieldDismissButton(.hidden)

Like .font, these modifiers apply to all numeric text fields in the modified view. SwiftUI's own .font and .foregroundStyle have no effect, because the field is backed by UITextField. For a custom font to follow Dynamic Type, create it with UIFont.preferredFont(forTextStyle:) or scale it with UIFontMetrics.

Focus

@State private var isEditing = false

NumericTextField(value: $amount, isFocused: $isEditing)
Button("Edit") { isEditing = true }

The binding works in both directions. It is independent of @FocusState.

Behavior notes

• Values set from outside with more fraction digits than allowed are shown rounded. When the field gains focus, the binding is set to the rounded value.
• Values exceeding maxIntegerDigits stay editable: deleting is always possible, adding digits is not.
• External changes during editing are not shown until editing ends. This avoids cursor jumps.
• Pasted text is treated like typed text: every . and , counts as a decimal separator. Grouped numbers like 1.234,56 are therefore rejected. 1.234 is read as 1.234 if maxFractionDigits allows three digits.

Limitations

• Negative numbers are not supported.
• There is no .onSubmit support. The decimal pad has no return key.

License

MIT, see LICENSE.