Picker onValueChange not being called on every selection - react-native

I have a picker with some hard coded values. On value change I want to update my redux store with the selected value using an action creator function from my store. I am running into an issue however where the onValueChange listener does not appear to be called for every selection change.
Picker code
<Picker selectedValue={this.props.settings.colorScheme}
onValueChange={(value, itemIndex) => this.props.onValueChange({prop: 'colorScheme', value})}>
<Picker.Item value="blue" label="Blue"/>
<Picker.Item value="green" label="Green"/>
<Picker.Item value="orange" label="Orange"/>
<Picker.Item value="purple" label="Purple"/>
<Picker.Item value="red" label="Red"/>
</Picker>
Method passed into component to handle value change. I set breakpoints here but they only trigger typically for every other selection. Start on blue, then choose orange it fires. Then choose green and it doesn't fire, but then choose red and it will fire again.
handleValueChange({prop, value}) {
this.props.updateSettings({prop, value})
}
Here is my redux action creator
export function updateSettings ({prop, value}) {
return {
type: UPDATE_SETTINGS,
payload: ({ prop, value }),
}
}
My render method (where onValueChange becomes handleValueChange)
render() {
return (
<Settings
settings={this.props.settings}
onValueChange={this.handleValueChange.bind(this)}
/>
)
}

I have found the folowing workaround using componentDidUpdate:
export default class PickerComponent extends PureComponent {
constructor (props) {
super(props)
this.state = {value:this.props.eventId}
}
componentDidUpdate () {
if (this.props.eventId !== this.state.value) {
this.props.chooseEvent(this.state.value)
}
}
onValueChange = value => {
if (value) this.setState({value})
}
makePickerItem (label, key) {
const props = {label, key, value:key}
return <Picker.Item {...props} />
}
makePickerItems = function * () {
for (let id in this.props.things) {
yield this.makePickerItem(this.props.things[id].name, eventId)
}
}
render () {
return (
<Picker
selectedValue={this.state.value}
onValueChange={this.onValueChange}
>
{[...this.makePickerItems()]}
</Picker>
)
}
}

Related

React Hook Form with Children in React Native

I have a form with ~15 fields where each section is a unique child component. I want to know how to pass data between the parent form and child components(using control because this is react native)
Right now, I see the proper value for testResult in onSubmit logs but data is undefined for some reason. This means my parent form is somehow not picking up the value in the child.
Parent Form:
const Stepper = () => {
const form = useForm({ defaultValues: {
testResult: "",
}
});
const { control, handleSubmit, formState: { errors }, } = form;
const testResult = useWatch({ control, name: "testResult" });
const onSubmit = (data) => {
console.log("watched testResult value: ", testResult);
console.log("form submission data: ", data);
};
return (
<WaterStep form={form} />
<Button onSubmit={handleSubmit(onSubmit())} />
)
}
Child component:
const WaterStep = ({ form }) => {
const { control, formState: { errors }, } = form;
return (
<Controller
name="testResult"
control={control}
rules={{
maxLength: 3,
required: true,
}}
render={({ field: onBlue, onChange, value }) => (
<TextInput
keyboardType="number-pad"
maxLength={3}
onBlur={onBlur}
onChangeText={onChange}
value={value}
/>
)}
/>
)}
Here I'm trying the first approach this answer suggests, but I've also tried the second with useFormContext() in child https://stackoverflow.com/a/70603480/8561357
Additionally, must we use control in React Native? The examples that use register appear simpler, but the official docs are limited for React Native and only show use of control
Update: From Abe's answer, you can see that I'm getting undefined because I'm calling onSubmit callback in my submit button. I mistakenly did this because I wasn't seeing any data getting logged when passing onSubmit properly like this handleSubmit(onSubmit). I still think my issue is that my child component's data isn't being tracked properly by the form in parent
The problem is most likely in this line:
<Button onSubmit={handleSubmit(onSubmit())} />
Since you're executing the onSubmit callback, you're not allowing react-hook-forms to pass in the data from the form. Try replacing it with the following
<Button onSubmit={handleSubmit(onSubmit)} />
For anyone still looking for guidance on using react-hook-form with child components, here's what I found out to work well:
Parent Component:
const Stepper = (props) => {
const { ...methods } = useForm({
defaultValues: {
testResult: "",
},
});
const onSubmit = (data) => {
console.log("form submission data: ", data);
};
const onError = (errors, e) => {
return console.log("form submission errors: ", errors);
};
return (
<FormProvider {...methods}>
<WaterStep
name="testResult"
rules={{
maxLength: 3,
required: true,
}}
/>
<Button onSubmit={handleSubmit(onSubmit)} />
)
}
Child:
import { useFormContext, useController } from "react-hook-form";
const WaterStep = (props) => {
const formContext = useFormContext();
const { formState } = formContext;
const { name, label, rules, defaultValue, ...inputProps } = props;
const { field } = useController({ name, rules, defaultValue });
if (!formContext || !name) {
const msg = !formContext
? "Test Input must be wrapped by the FormProvider"
: "Name must be defined";
console.error(msg);
return null;
}
return (
<View>
<Text>
Test Input
{formState.errors.testResult && <Text color="#F01313">*</Text>}
</Text>
<TextInput
style={{
...(formState.errors.phTestResult && {
borderColor: "#f009",
}),
}}
placeholder="Test Value"
keyboardType="number-pad"
maxLength={3}
onBlur={field.onBlur}
onChangeText={field.onChange}
value={field.value}
/>
</View>
);
};
Here's what we're doing:
Define useForm() in parent and de-structure all its methods
Wrap child in <FormProvider> component and pass useForm's methods to this provider
Make sure to define name and rules as props for your child component so it can pass these to useController()
In your child component, define useFormContext() and de-structure your props
Get access to the field methods like onChange, onBlur, value by creating a controller. Pass those de-structured props to useController()
You can go to an arbitrary level of nested child, just wrap parents in a <FormProvider> component and pass formContext as prop.
In Ancestor:
...
const { ...methods } = useForm({
defaultValues: {
testResult: "",
},
});
const onSubmit = (data) => {
console.log("form submission data: ", data);
};
...
<FormProvider {...methods}>
<ChildOne/>
</FormProvider>
In Parent:
const ChecklistSection = (props) => {
const formContext = useFormContext();
const { formState } = formContext;
return (
<FormProvider {...formContext}>
<WaterStep
name="testResult"
rules={{
maxLength: 3,
required: true,
}}
/>
</FormProvider>
)}
Thanks to https://echobind.com/post/react-hook-form-for-react-native (one of the only resources I found on using react-hook-form with nested components in react-native)
....
And a further evaluation of my blank submission data problem, if you missed it:
As Abe pointed out, the reason I didn't see data or errors being logged upon form submission was because onSubmit was not being called. This was because my custom submission button, which I didn't include in my original question for simplicity's sake, had a broken callback for a completion gesture. I thought I solved onSubmit not being called by passing it as a call onSubmit(), but I was going down the wrong track.

loading on navigating between screens

I'm new in RN. When I want to navigate between screens I create this function:
displayScreen2 = () => {
this.props.navigation.navigate("screen2")
}
and I call it in onPress={this.displayScreen2}
with TouchableOpacity or any Touchable when the user clicks he has to wait 1 second or 2 before displaying the screen. So what I want is to change the Touchable icon to an loader.
It's simple if I use a conditional rendering but I don't know how to do it now, when I have to change my state? Any suggestions?
this is my approach:
<TouchableOpacity
style={Styles.topButton}
onPress= {() => {
this.setState({loading: 'load'},
() => {
displayScoreListView()
// this.setState({loading: 'icone'})
}
)
}}
>
<Text style={Styles.scoreListButtonTextRed}>{this.state.loading}</Text>
that not work, tha state change but visualy not because if I return to the first screen I have 'load' in the text component
You could create a custom component wrapping whatever Touchable you prefer, I've used this technique in my production apps before. The button has it's own state which allows you to automatically display a loading indicator when necessary.
export class ButtonWorker extends Component {
state = {
working: false
}
onButtonPress = () => {
this.setState(
{ working: true },
() => {
this.props.onPress(this.onWorkFinished);
}
);
}
onWorkFinished = () => {
this.setState({ working: false });
}
render() {
return (
<TouchableOpacity>
{this.state.working ? (
<ActivityIndicator />
) : (
this.props.children
)}
</TouchableOpacity>
);
}
}
And then use it like a normal button with additional logic!
export class NavigationScreen extends Component {
navigate = (done) => {
// ... Asynchronous logic goes here
done();
this.props.navigation.navigate("Screen2");
}
render() {
return (
<Fragment>
{/* ... */}
<ButtonWorker onPress={this.navigate} />
</Frament>
);
}
}

Picker onValueChange() called twice

I want to support localization using react-18next.
This component shows a Picker, sets a LocalStorage key (the selected language) and change the app language.
I noticed the onValueChange method is called twice. The first call (using a proper selection tap action on a Picker item) have the correct parameter (the language I have chosen), the second call have the value of the first Picker item, whenever the values is (!).
Example: if I select the English Picker item, I see the Picker switch to English (first _changeLanguage() call), and then again to "Device" (second _changeLanguage() call). I'm sure it's an async ops problem, not sure where..
#translate(['settings', 'common'], { wait: true })
export default class Settings extends Component {
state = {};
constructor(props) {
super(props);
}
componentWillMount() {
this.getLang();
}
async _changeLanguage(ln) {
const { t, i18n, navigation } = this.props;
console.warn("_changeLanguage: ",ln)
await this.promisedSetState({lang:ln})
if(ln=="device") {
console.warn("removing lang setting")
await AsyncStorage.removeItem('#App:lang');
} else {
console.warn("lang setting: ", ln)
await AsyncStorage.setItem('#App:lang', ln);
i18n.changeLanguage(ln)
}
};
//get Language from AsyncStorage, if it has been previously set
async getLang() {
const value = await AsyncStorage.getItem('#App:lang');
console.warn("getLangfrom asyncstorage:", value)
if(value) await this.promisedSetState ({lang:value})
}
promisedSetState = (newState) => {
return new Promise((resolve) => {
this.setState(newState, () => {
resolve()
});
});
};
render() {
const { t, i18n, navigation } = this.props;
const { navigate } = navigation;
return (<View>
<Picker
selectedValue={this.state.lang}
onValueChange={(itemValue, itemIndex) =>this._changeLanguage(itemValue) }>
<Picker.Item color="#666" label="detected from device" value="device" />
<Picker.Item label="English" value="en" />
<Picker.Item label="Deutsch" value="it" />
</Picker>
</View>);
}
}
The code is based on the react-i18next Expo example
https://github.com/i18next/react-i18next/tree/master/example/v9.x.x/reactnative-expo
I'm not sure if this belongs here but if anyone is encountering the problem of onValueChange firing twice and is using react-native-picker-select instead of the default Picker then this solution may work for you.
I ended up using the itemKey property instead of value and setting the key of each item to be the same as its value. Note the example item would end up shaped like so: { key: 'value1', value: 'value1', label: 'Your Label' } where the key and value are identical.
Original Code:
<RNPickerSelect
style={styles.picker}
value={value}
onValueChange={this.onValueChange}
placeholder={placeholder}
items={options}
/>
Fixed Code:
<RNPickerSelect
style={styles.picker}
itemKey={value}
onValueChange={this.onValueChange}
placeholder={placeholder}
items={options}
/>
I got my inspiration from this: GitHub issue.
Searching around the react-native Picker seems bugged.
This quickfix solved my problem https://github.com/facebook/react-native/issues/13351#issuecomment-450281257

React Native setState does not refresh render

I try to get which is not active (in term of NativeBase.io - https://docs.nativebase.io/Components.html#button-def-headref, which simply means that it has no background color) and after I click it, it becomes active (it has a background color).
I define button like this:
<Button active={this.state.selected} onPress={() => this.select()} first>
<Text>Puppies</Text>
</Button>
selected variable in my state is by default false. When I run the application, it works correctly.
The select() method is implemented:
select() {
this.setState({ selected: true })
}
I expect that after I click on the button, it should change its background but it isn't. I check the value of this.state.selected and it changes appropriately. What I'm doing wrong?
export default class MyComponent extends Component {
state = {
selected: false
}
handlePress = () => {
const { selected } = this.state;
this.setState({
selected: !selected,
})
}
render() {
const { selected } = this.state;
return (
<Button active={selected} onPress={this.handlePress} first>
<Text>Puppies</Text>
</Button>
);
}
}

react-native reseting TextInput after ClearTextOnFocus

I am building a form in React-Native and have set ClearTextOnFocus to true as it is easier to handle dynamic formating for editing.
I am trying to add a reset function by setting all local state to the redux store, but if the user has not typed anything in a selected TextInput, the local state has not changed, and react native does not re-render the TextInput; leaving it blank.
Anyone have any thoughts on how I can unclear the TextInput or force React to re-render. Code is a work in progress, but here are the relevant bits.
Thanks
class GoalScreen extends Component {
componentWillMount = () => this.setPropsToState();
onReset = () => {
this.setPropsToState();
}
onChange = text => this.setState({ [text.field]: text.input });
setPropsToState = () => {
const { name } = this.props.goal;
this.setState({ name });
};
render() {
const { name } = this.state;
return (
<View style={styles.screenContainer}>
<Text style={styles.text}> Name </Text>
<TextInput
placeholder="a brand new bag"
keyboardType="default"
autoCorrect={false}
style={styles.inputField}
clearTextOnFocus
onChangeText={text => this.onChange({ input: text, field: 'rate' })}
value={name}
/>
</View>
}
}
So, I'm not using Redux, and my use case might be a bit different than yours, but I thought my solution might still be relevant here, if only to confirm that (after hours of wrangling with this) it appears that passing true to the clearTextOnFocus prop prevents further updates to a TextInput component.
I tried every conceivable workaround (like setNativeProps(), forceUpdate()) but nothing worked, so I ended up having to basically write my own logic for clearing and resetting the input text.
This component should 1) clear input text on focus and then 2) reset it to its previous value if the user hasn't pressed a key:
class ResettableInput extends Component {
state = {
Current: this.props.value,
Previous: ""
};
KeyPressed = false;
//cache current input value for later revert if necessary, and clear input
onFocus = () => {
this.setState({ Previous: this.state.Current, Current: "" });
};
//record whether key was pressed so input value can be reverted if necessary
onKeyPress = () => {
this.KeyPressed = true;
};
onChangeText = text => {
this.setState({ Current: text });
};
//if no key was pressed, revert input to previous value
onBlur = () => {
if (!this.KeyPressed) {
this.setState({ Current: this.state.Previous, Previous: "" });
}
};
render = () => {
return (
<TextInput
onChangeText={this.onChangeText}
value={this.state.Current}
onBlur={this.onBlur}
onFocus={this.onFocus}
onKeyPress={this.onKeyPress}
/>
);
};
}