I'm new to react native.
I need to create the front-end part of an app used to manage products. In this app, a specific screen lets users add a "new product".
I've almost finished the UI part, but I now need to show errors to the user when something is wrong with its input (a missing product ID, a description with less than 10 characters, etc.).
Here's my objective: when the user clics the "publish" button, I check all the inputs. If the input is ok -> nothing happens, if the input contains an error -> the field turns red.
To achieve this, I need to work with states. Here should be an example for the title:
style={[style.inputText, {color: this.state.titleColor}]}
And I can change the state.TitleColor if something is wrong with the title input.
The problem is that I don't want to create a specific state for each input (titleColor, IDColor, descriptionColor, etc.).
How can I do a common state for inputs that are correct, and an other state for inputs that are wrong? I thought of using an array (with inputCorrect:[] ;
InputWrong:[]), but I do not know exactly how to deal with it.
Can someone help me? Thanks.
I'd recommend using a form library to help you with state and validation. I personally like formik, but I've heard good things about react-final-form as well (both are compatible with React Native).
Libraries like this make it easier to manage validation and input state, because they manage the state for you and tell each of your fields whether they're valid or not (passing appropriate error messages if needed).
It's still up to you to build the UI that displays the errors, but having the logic taken care of is a huge help. The formik docs have some good examples showing you how you would achieve your goal of changing a field color to red if that field has errors.
There is a bit of a learning curve to understand how to use these libraries well, but it's well worth it in my opinion.
Related
I am using the react-autosuggest library to implement auto-suggestions functionality. I am pretty new to using this library. I went through the documentation, but it seems to be a bit confusing to me in certain things.
I tried to find answers to a few of the things:
What is the complete list of inputProps that can be passed to the component?
How can we open a dropdown with a list of a few default suggestions as soon as the user clicks on the input box instead of showing suggestions only when the user types in?
What exactly is the use of prop: multiSection when the data is of the form [{ name: '', flag: ''}] (just a sample) and we display only name in the dropdown list?
I found a lot of similar working examples using this library but wasn't able to get hold of the understanding properly. Seems like there are lots of missing points in the library documentation.
I found this one basic clean working snippet: https://codesandbox.io/s/react-autosuggest-example-with-hooks-forked-y7lkom. But was unable to add the dropdown functionality to it.
If anyone can help to get through this feature and some above queries, I would be highly thankful.
I am working on order automation for Trading View.
Although I have been able to make some progress, changing the price for limit orders (as well as the quantity, any number) has been a challenge. I am able to change the value on the input but it doesn't really get updated in the app model (hence the buy button never reflects the change).
Any help will be highly appreciated.
Best
Sometimes the view of the value is not bidirectional connected to the hidden input field. Seems like the trading app is using some reactive framework, they usually integrate some UI components library, and those libraries hide the real input field in behind the beautiful mask of the ux oriented view on the front side.
Here you have 2 options
Try to set the value of hidden input field in behind the component and try to send the request to see if the new value is fetched, no matter if its visible on front or no
I think more user friendly option, to trigger the events on the HTML elements, this will require more research from your side to learn how to trigger events and check the results of those events step by steps. If you already know it then it will be fast.
For Example:
// Let's say pure js
// Keep in mind, id of element, not a hidden input field.
const dropdown = document.getElementById('idOfHTMLElement');
dropdown.click(); // After click the options of the dropdown should appear
const options = Array.from(document.getElementsByClassName('classNameOfDropDownOption'));
const desiredOption = options.find((option) => option.someConditionLikePriceOrSmthElse: boolean);
desiredOption.click();
// Something like this, not accurate code, please test and correct if you will use this
I'm having some difficulty envisioning a potential solution to a dilemma I'm facing, and I need some creative inspiration.
Essentially, I'm struggling to picture a good way to validate a form that can be thoughts of as having multiple nested forms. The challenge is that these nested forms are only rendered when a line item in the main form is clicked, causing a modal to open, at which time the rendering, model binding, etc. takes place, and the nested form can be validated.
The goal is to know whether or not there are validation errors down inside any of the main form's line items without having to open/render a modal for the item to find out. I'd also like to make sure that there's no duplication of validation logic, and that things are drawing from a single common set of validations rules that can be shared/accessed everywhere needed.
Ideally, I'd like to abstract out the validation logic such that it can be used by any ng-model bound element, but can also be used independent of rendering a form.
If anyone knows of any plug-ins that work well with AngularJs and sound well suited, please let me know.
Clarification
Though I'm open to checking out any plug-ins that might help, that's not really what I'm after. My main objective to is to find a way to validate my nested item data without opening/rendering the item's modal.
I would use something that ensures that the user fills in these forms in a predefined format in the first place.
I use something called inputmask in my angularJs applications.
You can use a regex to define the format you want the inputs to be in.
You can also make sure that all the fields in the modal are in the right format before letting the user close the modal(This validation logic can come from a shared or common component).
Another option would be to make the modals hidden and not removed from the DOM so that the bindings remain even when the modal is no longer visible. You can add a red asterisk or something against the line which opens the modal to indicate errors in that modal's form.
I've never worked with Ember, and am fairly new to JavaScript, and have for the past couple of days been trying to translate my HTML and JS into the Ember framework (I got some help from a friend). The first feature of the project should simply be able to fill a text-field with longitude/latitude of an inputted address. The second feature of my project is based on a selection from a drop-down menu (drop-down is made of different counties), and fill another text-field with a specific email address depending on which selection was made.
The problem I'm having: I can't seem to figure out how to fire up my setEmail function as I need it to recognize a value (1, 2, 3, 4 etc.) from the selected county from the drop-down, and based on that value; fill in the text-field with the correct email address. I've heard about Ember Observers, but cannot seem to figure out how to implement them for the drop-down I built. I'd really appreciate if someone could take a look at my project and give me pointers on what I could improve, or even do completely differently.
Here is a link to an Ember Twiddle of my project: GeoApp
I appreciate any suggestions and insight! Thank you.
The main idea was right, you were just missing small details. x-select has an "action" hook that you can use which is being triggered every time the value of the x-select changes. This also passed to you as an argument the selected value.
Also there was no need to make the as |xs| part and the options should be set as {{#x-option value='country.value}}country.display{{/x-option}}
Doing all this will make it work. You can find a working twiddle here.
Yesterday I discovered that jQuery is really powerful and can do amazing things with only a few (sometimes just one) line of code, amazing! I did some animating which went really well!
So I was wondering if the following is also possible/ simple to implement with jQuery (if not, please tell me what could do this):
Basically I want a suggestion mechanism for the webapplication we are creating. We are doing this using ASP.NET MVC 4. By suggestion mechanism I mean the user gets presented with a textfield, he can start typing and based on his typing topics (I have a model class Topic with a few properties) get suggested. The user can ONLY choose out of those topics, they can't define any by themself. So I would like to generate a list based on the input (with each key tap). If they click on an item, it gets added to the box and they can choose other topics if they would want to.
I do realize that this is probably rather difficult to implement, but it would be great if I could find a tutorial or example. Preferable with JavaScript or jQuery, but if that's not possible anything will do really!
If my explanation is not clear enough: I mean something similar to the StackOverflow suggestion mechanism for tags.
If you want suggestive text field, search for html5 datalist datalist
Also take a look at JqueryUI Auto Complete
However if the options are not too much, i would go with select menu instead of text field.