I have a button on my header right that open up a drop down component. The component allow user to make some selection and apply it after the user hit the 'apply' button.
After the apply button pressed, it should be able to pass the value back to the 'main screen' component. How do I pass the value back to the 'main screen' ?
This is my interface , if you're wondering what I'm trying to do.
edit
I tried to pass in the useState function to the header component to update the state after the apply button pressed by passing it using the setParam from react navigation props. Is there any other better way to get the value ??
You can do it simply like:
props.navigation('Home', { state: SOME_VALUE });
Here is the react navigation doc to do this.
React navigation passing params to previous screen
Or you can use redux store.
Related
First-of-all I apologise because I'm new to this concept of redux haha so bare with me here :)
I have implemented a very simple redux in my app
I have one screen here ListAnItem
Here there is a button.
Add size when pressing this they get navigated to another screen called SizeSelector
SizeSelector
here there is a button called dispatch size when they press this button it runs the following.
dispatch({type: "ADD_SIZE", payload: size })
this works perfectly with useSelector.
once this dispatch has been run I use navigation.goBack() to send the user back to the ListAnItem screen.
but once they come to this screen I want to add this useSelector redux state value to a useState hook something like this;
const [sizeState, setSizeState] = React.useState(null)
how can I change this state the minute something has been added to useSelector value of ADD_SIZE.
if that makes sense 😂.
Thanks,
Arnav.
I know this is a stupid question.
I have a component lets call it Component that is used in several screens for Example Screen1,Screen2,...
And in the Component I am navigating to a new Screen when the user click a button, lets call it ImagePicker.
my Question is how do I go back and pass a parameter( in this case image data) and get it back in the Component
I tried using navigation.goBack({img: image}) but that didn't work. I also can't use navigation.navigate('Screen') since my functions are in the Component component.
So what is the best solution for my problem ?
We cannot pass any params to the goBack method.
If we have to do so then, we can use the navigate method to navigate to the back screen, and using this method we can pass the params to the previous screen.
For ex.
navigation.navigate('PrevScreenName', {key: value})
Check out the official docs for the react-navigation.
React Navigation
If I understand your problem well, just do
navigation.navigate('Screen', {img: image})
instead of navigation.goBack({img: image}) and it should work
In the component code, I would pass along a callback function to the image picker screen
handleImageData = (data) =>
{
// do whatever
}
...
navigation.navigate('ImagePickerScreen',{mycallback:this.handleImageData});
and then in the screen code just call it like
this.props.route.params.mycallback(data);
navigation.goBack();
I would like to know if it's possible to set the state to the initial state values whenever we press back the button in the tabBar ? At the moment, when I leave the tabBar and come back after a few navigation in the app, the infos that the user enter in TextField persist.
Thanks !
You could use React hooks to achieve similar results to lifecycle methods in class functions.
The useEffect method runs on component render. You can set the state in there.
const [currentState, setCurrentState] = useState(null);
useEffect(()=>{
// This will run after 1st render
setCurrentState("");
},[]);
I have a snack setup:
https://snack.expo.io/#sj458147/view-not-scrolling
when you click show modal -> Click next button the View horizontally scrolls (animated), which then displays an image carousel. Now when you click an image, the View should horizontally scroll again but I get the error undefined is not an object. The error lies within the file:
SliderEntry.js
select = () => {
this.MyScrollView.current.moveToPage(3);
};
any help resolving the issue would be appreciated. Thanks in advance
You have MyScrollView ref in ShowModal. There are 2 ways:
Not recommend: Pass MyScrollView ref as props to Slider, then pass to SliderEntry
Recommend: create a callback as props in SliderEntry. Callback to Slider, then callback to ShowModal
Pass your function in props to other components and then access these functions from your another component.
You can find the answer here
React : Pass function to child component
Example:
Lets say you have a screen with list items loaded into this.state.items.
Now you have a button that navigates you to a new screen.
On this screen you want to append an item to that list.
Once you dismiss that screen, you'll be back at the screen with the original list items.
What is the best way to achieve the goal of updating that list with the new item?
Should this be done by:
1. Passing the new screen the this.state object.
2. By calling an update function on the old screen? (Function probably passed as a prop to the new screen.)
3. Using the StackNavigator's prop in function?
4. Another way?
I appreciate any help.
You should pass a callback that updates the state through the navigate action:
this.props.navigation.navigate('NewScreen', {
addItem: item => this.setState(prevState => ({ items: prevState.items.concat([item]) })),
});
Then call it in the new screen to add an item:
this.props.navigation.state.params.addItem(newItem);
Using a state management library like mobx if your component state is extracted into Stores, the second screen component can update the store and all components that injects this store will be auto updated.