How can I mutate inputted textField's String with binding action?? #3062
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Hellow everyone! My development eviroment
I want to muate inputted textField's String. ex) lowercased, trimmingCharacters, prefix... I referenced Working with SwiftUI bindings I tried three ways but not works😂 first trystruct ContentView: View {
@Perception.Bindable private var store: StoreOf<ContentFeature>
init(store: StoreOf<ContentFeature>) {
self.store = store
}
var body: some View {
WithPerceptionTracking {
VStack {
TextField("test", text: $store.textFieldText.sending(\.textInpuuted))
}
.padding()
}
}
}
@Reducer
struct ContentFeature {
@ObservableState
struct State: Equatable {
var textFieldText: String
}
enum Action: BindableAction {
case binding(BindingAction<State>)
case textInpuuted(String)
}
var body: some ReducerOf<Self> {
BindingReducer()
Reduce<State, Action> { state, action in
switch action {
case let .textInpuuted(text):
let newText = text.lowercased()
state.textFieldText = newText
return .none
default:
return .none
}
}
}
}second trystruct ContentView: View {
@Perception.Bindable private var store: StoreOf<ContentFeature>
init(store: StoreOf<ContentFeature>) {
self.store = store
}
var body: some View {
WithPerceptionTracking {
VStack {
TextField("test", text: $store.textFieldText)
}
.padding()
}
}
}
@Reducer
struct ContentFeature {
@ObservableState
struct State: Equatable {
var textFieldText: String
}
enum Action: BindableAction {
case binding(BindingAction<State>)
case textInpuuted(String)
}
var body: some ReducerOf<Self> {
BindingReducer()
Reduce<State, Action> { state, action in
switch action {
case .binding(\.textFieldText):
let newText = state.textFieldText.lowercased()
state.textFieldText = newText
return .none
default:
return .none
}
}
}
}thrid tryimport SwiftUI
import ComposableArchitecture
struct ContentView: View {
@Perception.Bindable private var store: StoreOf<ContentFeature>
init(store: StoreOf<ContentFeature>) {
self.store = store
}
var body: some View {
WithPerceptionTracking {
VStack {
TextField("test", text: $store.textFieldText)
}
.padding()
}
}
}
@Reducer
struct ContentFeature {
@ObservableState
struct State: Equatable {
var textFieldText: String
}
enum Action: BindableAction {
case binding(BindingAction<State>)
case textInpuuted(String)
}
var body: some ReducerOf<Self> {
BindingReducer()
.onChange(of: \.textFieldText) { oldValue, newValue in
Reduce<State, Action> { state, action in
state.textFieldText = state.textFieldText.lowercased()
return .none
}
}
Reduce<State, Action> { state, action in
switch action {
default:
return .none
}
}
}
}I also referenced Performance as I read sending actions is not lightweight so mutating inputted string every time looks not good. Is there any good way mutating inpuuted string?? |
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Replies: 3 comments 6 replies
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Hi @JongHoooon, this is just a limitation of SwiftUI in general. If you were to recreate this app using either @Observable
class Model {
var text = "hello" {
didSet {
if text != text.lowercased() {
text = dump(text.lowercased())
}
}
}
}
struct A: View {
@Bindable var model = Model()
var body: some View {
Form {
TextField("", text: $model.text)
}
}
}I believe the way SwiftUI wants you to do these kinds of transformations is through formatters, which is an additional argument you can pass to |
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Thank you @mbrandonw As I know Using formatter works when keyboard return button tapped. I want to check and mutate everytime user input string. I also tried not using action. It works well. Is this related to performance(action is not lightweight ) ?? var body: some View {
WithPerceptionTracking {
VStack {
TextField("test", text: $store.textFieldText)
.onChange(of: store.textFieldText) { newValue in
store.textFieldText = store.textFieldText.lowercased()
}
}
.padding()
}
} |
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That trick seems good to me! |
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I've found the same problem. In my case I wanted to limit the length of the String that is typed by the user. I need to modify the length of the String so that when the user erases one character, the character is deleted from the limited-length String. Did you find a solution to this? |
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Hi @alvarezGarciaMarcos, there is a solution from @JongHoooon in the discussion above. |
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@JongHoooon @alvarezGarciaMarcos @mbrandonw |
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For what it's worth, this does not mutate state outside of the reducer. Doing |
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I thought it was directly modifying the state, but it wasn't. Thank you for letting me know. |
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I know it was not directly modifying the state. but I think view had business logic looks not good. I want to handling every business logic in the reducer. |
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That trick seems good to me!