textSelectionAffinity(_:)
Sets the direction of a selection or cursor relative to a text character.
Declaration
nonisolated func textSelectionAffinity(_ affinity: TextSelectionAffinity) -> some View
Parameters
- affinity:
The text selection affinity strategy to apply.
Return Value
A view that uses the specified selection affinity strategy.
Discussion
Use this modifier when you need to handle line breaks in a specific way, alter cursor movement or deal with bidirectional text (text that contains both LTR and RTL scripts, like English and Arabic combined).
Selection affinity also determines whether, for example, the insertion point appears after the last character on a line or before the first character on the following line in cases where text wraps across line boundaries.
Given the scenario hello|مرحبا, where | represents the cursor & مرحبا represents “hello” in Arabic, the ambiguity arises because:
If the cursor is associated with the end of the English word, it would be as if you’re continuing to type in English (LTR).
If the cursor is associated with the beginning of the Arabic word, it would also be as if you’re continuing to type in Arabic (RTL).
This modifier helps resolve this ambiguity by determining the direction or association of the cursor relative to the surrounding text.
The following example shows how you would specify a specific selection affinity on the given hierarchy:
struct SuggestionTextEditor: View {
@State var text: String = ""
@State var selection: TextSelection? = nil
var body: some View {
VStack {
TextEditor(text: $text, selection: $selection)
// A helper view that offers live suggestions based on selection.
SuggestionsView(
substrings: getSubstrings(text: text, indices: selection?.indices))
}
.textSelectionAffinity(.upstream)
}
private func getSubstrings(
text: String, indices: TextSelection.Indices?
) -> [Substring] {
// Resolve substrings representing the current selection...
}
}
struct SuggestionsView: View { ... }