markdown guide
 

What do you think about start app using expo? Is better start app with react-native Cli?
What package do you recommend for UX?

 

No, I would never use Expo for a serious project. I imagine what ends up happening in most projects is they reach a point where they have to ultimately eject the app (e.g. needing a native module) which sounds very painful.

The majority of the apps I've wrote have definitely reached that point, for the individual benefits expo provide (e.g. code push) I've considered trying out using just expo kit but I'd rather just uses a tool specifically for that purpose. Above all, I always like to reduce the level of magic in any application, mobile or not.

Regarding "What package do you recommend for UX", I guess it really depends what you mean. But hopefully this gives you everything you need to know:

  • For navigation I use react-native-navigation, can't recommend this enough as it adds a massive difference in fidelity vs using JavaScript based lib like react-navigation.
  • For interactive elements (drag drop, sliders, parallax etc) I use a forked version of react-native-interactable.
  • For custom vector animations e.g. button icons I use Lottie.
  • I do not use a framework for developing styles/grid layouts (e.g. glamourous), I've got my own base-layout of styles and components.
 

I'm very grateful for your answer, this is very helpful !! 😊

I use always expo because I'm starting programming in RN, but I think I will start starting project with react-native-cli.

 

This is a really good question, in a meeting at the moment but will definitely respond to this!

 
  • What do you think about the fluidity of react-native apps ?
    So far, I've seen apps made by Chinese e-commerce giants like Alibaba's Taobao and Jindong, their apps requires lots of resources and are all very slow even on last end Android devices.
    I've also seen some startup using it for chat app and it's simply become unusable after a while because all the memory leaks.

  • Do you think these are just poorly made app or react-native is just not ready to replace native development ?

  • Which app would you recommend to check out in order to see how powerful this framework can be ?

 

The only case I've seen that can be tricky to keep performant at the moment is when you're doing CPU heavy tasks whilst listing out uncompressed images >2mb. Memory consumption of images this size do seem to be a tricky problem, though libs like react-native-fast-image aim to solve this sort of thing.

I'd say almost certainly they were developed badly, there's no reason now why you couldn't make apps indistinguishable from native. My top tip for this is to move away from JS based navigation libraries (e.g. react-navigation), that's where you see a lot of the performance gains.

Performance wise the Patient View app I made shows this off, I sync and encrypt thousands of records and chart them out whilst keeping everything 60fps.

 

I see, thanks for the answer and cheers for the 100 apps, that's a hell of a pace :)

 

Hey kyle, that's wonderful.
I have a question for you please.
I see you use rnn just like me so how do you tackle showing perticular screen after opening app from notification.
E.g user received a notification message in a chat app As app is killed. Now user taps on the notification and app opens. Now how do you redirect to perticular chat? I tried with handleDeepLink but its slow.

 

If you haven't moved to RNN v2 by now, I'd recommend it ;)

 

Cool :) I just moved a big project to it, I don't feel like it's perfect yet but still a big improvement over v1. I actually don't understand why so many people are happy with JS based navigation like react-navigation.

Hey Kyle, but could you please point out how you tackle this problem with opening app on the specific screen (using RNN v2) after clicking on push notification in tray? What package do you use for handling push notifications?

Hey Kyle, but could you please point out how you deal with opening app on specific screen after pressing push notification from tray (using rnn v2)? What package do you use for handling push notifications in conjunction with rnn v2? maybe you could point out to some great examples?

 

I solved this problem.. If you wish to know ? Ping me

 

Hey Faiz, were you able to solve this issue? could you please elaborate on what package you used for handling push notifications?

 

What are the most 3 troublesome issues with React Native and how did you overcome?

 

1 - Upgrading projects from very early versions of React Native. This has been, at times, an absolute nightmare (mainly iOS)! Especially when your project relies on several libs that require native changes. In the end, it was often easiest to create a new react native project from scratch and manually link libraries one by one.

Thankfully, this is rarely an issue now as it has matured. Having said that, I think it's really important to stay on top of React Native versions if your project has longevity.

2 - I had to integrate a react native app to read sensors for a car HUD, no simple way of overcoming this I just had to learn Objective C to write a React Native Bridge. Getting comfortable doing this is really valuable if you run into projects that require specific native functionality.

3 - Once, I hit an error which I could only replicate at the point of uploading a react native app, it would error out with "You must supply a CFBundleIdentifier for this request". This had me banging my head against my desk for a few days. In the end, it was something simple like the way I was creating my release scheme in xcode.

 

on #2 you said that you have to learn Obj-C.

Is is still worth it to learn Obj-C or go straight with Swift if we need to write native modules for our RN project?

I feel like it’s actually more useful to learn objc if the purpose is purely for react native. The reason I say this is a lot of the big native modules for rn are written in it, rarely came across swift implementations.

 
 

As shown in here (youtube.com/watch?v=0MlT74erp60&fe...), I need CPU profiling for react-native javascript code.

So can you please explain/guide me to tutorial for profiling javascript code?

 

Apologies, I don’t have much to share around this. Though I’m sure there’s plenty of resources out there for this.

 

I'm working on my second app now, but this will be the first one I release. My biggest fear going in to this is not building that app, but the red tape of getting it published. With that being said, my questions are.

  • What should I be prepared for when going to publish my app?
  • What can I do to help avoid headaches during the process?
  • How hard much harder is it, to publish both Android and IOS, vs just IOS?
 

Good question and congrats :).

How hard much harder is it, to publish both Android and IOS, vs just IOS?

To get the last question out of the way, I'd say if you face any red tape it's almost certainly going to be on iOS side. Also the time bottleneck is going to be iOS side too, publishing can take 1-2 days but sometimes more.

What should I be prepared for when publishing my app?

I can't give you a simple one sized fits all answer here, but I would say that as long as you're not doing something outrageous you'll probably be ok. Best thing I can do is list some of the common scenarios I've found that might catch you out:

  • If you're using media that's subject to copyright you may need to prove you have rights to use it (we had to prove we had rights from opta for developing dugout FC)
  • If you're using chat (particularly anonymous), you'll need a way for users to report people and block people.
  • If you're developing an app for a client who has a registered organisation you need to make them register their own iTunes connect account with their iban, don't try to use your own.
  • Your app needs to have a functional use and can't be purely informational.
  • Your app needs to be useful in someway shape or form for anyone that could come across it, not just specific users (e.g. invitation only)
  • If you're attempting to white label an app, iOS state there needs to be a functional difference and not just informational.

With the above being said it literally depends sometimes on who views it.

What can I do to help avoid headaches during the process?

  • Put the app through the review process early for iOS, if you check the option for manual release you could just leave it there and keep developing.
  • Get all of your metadata early. There are tools for generating all sized icons, take screenshots of the app in the biggest iPad and iphone, you'll need these to submit, iTunes connect can now auto resize to smaller devices.
 

You rock and that was greatly informative. Thank you so much.

That's alright, enjoying all these questions!

 

Hi Kyle,

I have TV-screen where we simply run our web-app on react. I have found out that fps starts slowly go down after ~10-15 minutes. It can loose 5-7fps per hour. App starts with 58fps and goes down to 52fps in one hour.

I had a test where I have webpack + App which renders empty div. This simple app starts to loose fps in 10 minutes after launch.

Is react suitable for apps which suppose to run without clicks and refreshes for hours? (is it problem of my app or the problem of react? Is there anything what could help me?

My backup plan is to refresh the page every hour, but I am looking for a better solution.

BR,
Julia

 

Hey Julia, although this is more of a react than react native question I’ll see if I can help point you in the right direction. This definitely seems quite unusual and isn’t standard for react to see this.

To me it sounds like some form of leak, e.g registering event listeners that don’t get unassigned, or some recursive hell. Did you try compiling your app in production mode and running the output with a simple http-server? Also, have you tried running in chrome and inspecting memory and cpu usage?

 

I have tests not only on dev but also on production of other product, which has the same results. FPS slowly goes down in some time.
This is why I raised the question if react suits for such products.

Probably, there is a problem in a set-up somewhere and react is not involved in the problem at all.

 

What is the major benefit over React (web)? Of course for apps where you need access to the users music for a music player it makes sense, but for festivals for example a web app app should be sufficient.

 

It ended up being an amazing app store SEO hack, a lot of the time we were the top search result for x festival - that's a lot harder to achieve on a website.

Also, quite simply, people take their phones to a festival not their laptop. This worked offline and tapped into things that only fit well on an app (e.g. find my tent, chat with image upload). It was definitely a lot easier to compete against the official app than website.

 

Emotions:

Sounds fantastik! This is your glory day, horray!
Each 10th day – new app!
I would like to give you 100 hundred copy-pasted emoji beer.

Question:

What is percentage of bridging to native modules?

 

Low, less than 10% maybe, but I've worked on some weird projects. There's so many repos now on GitHub when comparing to 2015.

Here are the times I've had to delve into native modules.

  1. Fixing bugs in existing libs (e.g. react-native-navigation)
  2. Developing an app that integrates to a car HUD (Had the innards of a car on my desk for months)
  3. Writing a bridge that integrated with a custom bit of hardware we produced base on particle.io/
  4. Writing an iOS native keyboard extension (there wasn't a good project that existed, I guess it's not a common use-case)
  5. Writing an android module that talked connected to a hotel router.
 

Was anything except Keyboard Extension on iOS? For example connection ABAddressBook written on ObjectiveC.

Interesting your integration approach with CoreML for example.

All the above required me to write ObjC. The HUD app in particular required me to bridge a pretty beefy SDK that was pretty closed off to the public.

I haven't integrated with core ml, I do want to play around with using tensorflow and React Native at some point.

 
 

It's a bloody pain!

I think I've got a post somewhere in GitHub saying this is the biggest pain point at the moment with core React Native, and I posted that in 2017 github.com/facebook/react-native/i....

I just use a combination of the keyboard avoiding view and react-native-keyboard-aware-scroll-view, I've always been able to achieve what I want but it's always fiddly.

 

Hi I'm diving into an already existing react native project, which hold a ± of 100.000 users. For now it's quite static and I was asked to add more delight and interaction to the app. On my research for this I stumbled onto the Lottie library, integrated into react-native. I tested it on my virtual machine and it looks amazing. But I have some questions though:

  1. Is it stable to use in real life products?

  2. Are there do's and don'ts for the use of this library? (like 'Use it for buttons, but definitely don't use it for...)

  3. When using this in live projects, did you often have performance issues?

If you find the time I'd love it if you could enlighten me on this. :D

Have a nice day!

 

TD: I mainly focus on functionality and leave interaction design to colleagues. However I consistently use Lottie in production.

  1. Yeah, the bridge is quite slim and regular Lottie is solid.
  2. The limitation I guess comes down to the fact that it's compiled down to JSON. Technically you can edit this JSON in realtime to adjust colours (I've done this for example with loaders that needed dynamic colours). It's mainly that it'd be tedious to build big customisable components when you're using minified JSON as the animation.
  3. No.
 

-> My source uri ImagebackGround is not loading in released apk on some latest devices(Notched, Curved).
-> Running absolutely fine when i build it on device. I am using ImagebackGround inside a card of native-base.
-> My source uri is a coming from REST API JSON.

Please help.
Thank you.

 

Hi There, we have built an app in React Native and have released it on IOS and Andriod. We have had reports of the white screen of death on IOS devices and so far only on iPhone 8s. The white screen appears not on the home screen or after splash screen but when taking steps beyond the home screen.

We have no issues on the simulator and therefore it is really hard to track an find. Let us know if you have any tips or start points?

 

Hey, unfortunately I can safely say I haven’t come across a white screen issue on any of the apps I’ve made. The only thing close is at the start screen where either the app is not registered or the packager is having issues.

 

Hey Kyle!!! I am new to react native and i am trying to work on user location tracking and sending it to another user. since i am new to react native and fire base i am facing problem to initiate. So, can you help me with this and say what to do?

 

Hi Kyle,

I have some weird issue with keyboard and scrollview.
I am using KeyboardAvoidingView and KeyboardAwareScrollview components to handle the keyboard.
The case is that when the keyboard get opens the cpu goes nuts.
Do you have any suggestion for this issue?
thepracticaldev.s3.amazonaws.com/i...

 

I am trying to get react-native-navigation and react-native-firebase to work together. I'm fairly new to programming and I'm having trouble getting them to build. I have seperately loaded react-native-navigation with react native version 0.56 and have used the starter program for react-native-firebase but not together. How do a build them together with react-native verison 0.58?

 

How many of them do you actively maintain?

Can you give a few examples of some of them?

 

Only a handful, which is a bit annoying because my xcode organiser / itunes connect etc ends up looking like this :D. prntscr.com/klu0jm

A lot of them have been released for a temporary period, due to them being PoC's or only having a limited shelf life (e.g. my festival apps). Other's just get taken over by other people post MVP.

A few that I'm maintaining, I'll add to this list in the coming weeks too if there's appetite :)

 

Hey Kyle! I really need your advice because you're using react-native-navigation. I used RNN v2 in my first RN project and almost in the end I am having huge troubles integrating it with push notifications. It seems absolutely not convenient and buggy with very sparse documentation. Already tried react-native-fcm and wix own thing react-native-notifications. Having issues making to to play nicely. besides that on Android RNN restarts the whole app when you click on notification in the tray. Could you please tell what package do you use for notifications and possibly point to some great examples of making that work togather on both platforms?

 

how can software engineer make a difference in a country?

 

What's your experience (if any) been like with RN-web?

We're considering rewriting an existing hybrid app to RN w/web, uses camera but no other hardware. I read above that you wouldn't recommend create-react-natve-app? For first timers, would you recommend using that, then when comfortable rewriting instead of ejecting?

Thanks!

 

I haven't used it. I love the idea of sharing web code with react native, but I don't think that idea should go as far as to share dumb components so I probably wouldn't use it. I haven't gone through the process of ejecting an app but I've been told it's really painful, but it's probably not quite as bad as rewriting from scratch.

Sharing code with web was what got me into react native in the first place, I don't think that benefit is talked about enough.

 

Hi Kyle, I'm new with RN and am developing now for 1 month. I was wondering if you could help me out on which version of RN is the most compatible version for app release and fewer errors, cause I've faced errors that made me downgrade a lot. Thank you so much for your attention.

 

Also do you have any tutorials you could point out to building react native bridges and projects which android native requires libraries written in C

 

I don't, and to be honest I've always been out of my comfort zone doing it. Ironically, as a result, I'm more comfortable reading ObjC than Java as I've bridged more in iOS even though I spent the first 2 years professionally writing Java.

I'd love (if I had the time) to progress more in native development, I think it'd be the thing that'd help me become a better React Native developer. Realistically you can achieve absolutely anything so long as you have the Native Code to back it up.

 

Hello! I'm developing react native application with expo and I have very strange bug. When I add new images, they are showing in my simulator and real device when I open it local, but when I'm publish project in expo.io, and after that when I open it in expo, new images are missing. But old images are showing! I use Image and Animation.Image from react-native. When I add new svg images in SvgUri component, it's reproduce too..

example of my code:

it's worked:

example of my code:

it's dont work:

Please, help me
Thanks a lot

 

I really can't help you here, sorry. I don't / will not use Expo - it sounds quite specific to Expo.

 

Hey I am currently working in REACT NATIVE project. Our team is using Sectionlist component and we would like to implement drag / drop functionality with section. I need to move items from one section to be other using drag / drop. I was able to make the items draggable by using panresponder api. But how to get the reference of drop zone ? When the item is dropped, I need to know to which section I have dropped the item. Can you please share your thoughts on the same.

 

How we can get a better debugging experience? When I was trying to develop some React Native apps and has an error, the stack trace were so confusing. There is a way to have a great debugging session with breakpoints, watches... and don't need to keep changing our code until it works?

 

I guess it depends where the error sits, some errors are hard to debug yes , either errors in the render markup itself or in native modules.

However I would say apart from that it's pretty much like debugging any web app in chrome with watches and other stuff you mention. I'd even go as far as to say developing with hot reloading is better than the react/webpack equivalent.

 

I am implementing a app using expo. But now i need to add a image recognition part to my app and i used the tensorflow for that. But it cannot be done with the expo. So do you have any solution rather than ejecting the app. I mean like to use the Firebase mlkit without using tensorflow or something like that.?

 

Can you help me to automate all kinds of task from building to releasing app to the store in React Native? I prefer circle ci or same kind of provider with good User Interface. I am looking for Continous Integration as well as Continous Development using React Native

 

Hello. I want to save my images on cloud drives(Google drive, dropbox...) with react-native app. I can't find out the exact way. I don't know which package I should use. What I have tried is getting auth but I can't understand how it works and how to manage my key or status. Can you give me any advice? Thank you for reading.

 

Hi Kyle,

I'm supposed to develop an RN application with location tracking (foreground,background & killed state). The feature works well with standard android os's, but fails in chinese manufactured devices like Xiaomi ,OnePlus etc. I've tried various libraries and workarounds but nothing worked perfectly.

Can you suggest something on this ?

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