react-native-tutorial | GitBook의 react-native-tutorial-korean 의 실습 코드 입니다 | Frontend Framework library

The problem was in rebuilding the app. It turns out that the command react-native run-android would build the app the first time it was run, but not any subsequent times. I've written a bash script with the following code to force a rebuild on an app every time it's run.

Put this in a bash script and run from the project directory

The app was on the device; it just didn't start immediately. I was able to find it by checking the apps list thoroughly. It seems that in some environments (like my loaner described above), the app with start on its own, and in other environments, it needs to be manually started.

Answering my self, I run this yesterday so the app was already installed on the emulator.

The cmd command :

Found the answer here https://www.codementor.io/vijayst/build-react-native-retrofitting-ios-app-to-android-gsf5uyl1q in the very 1st paragraph and it is exactly what I have been trying to get RN/Facebook answer but they ignored the question all the time.

Very disappointing!

So, ReactNative is not "build-once-use-everywhere" but rather "learn-once-use-everywhere" meaning lots of code duplication. And by everywhere, they mostly mean Android and IOS although the examples out-there are mainly IOS. If they cover both platforms, then it is with almost no code sharing but lots of code-duplication.

Although, RN claims they can achieve up to 90% of code sharing, that is not demonstrated anywhere that I could find. Documentation is very shallow in touching anything let alone topic of code-sharing and the tutorial provided by RN is a HelloWorld, ... yes, seriously. Sad! Although they used to have a better tutorial in older version (like 0.20 or so).

In terms of recommending RN to a company as a next-gen platform, I see few issues

• concerning patent license, no answers no explanations, very obscure and concerning for a company that would consider moving to this, I'd rather say open-source under quotation marks. Hopefully this will change as I see it as a mayor showstopper for anyone considering adapting this technology. I would say this is no more applicable as FB made react-native licensed using MIT as per https://github.com/facebook/react-native/issues/16079

• documentation that is very basic without giving depth of explanation. For example, this is react-native site with demo sample to demonstrate code-sharing cross-platform nature (I warn you, it is a HelloWorld example) https://facebook.github.io/react-native/docs/tutorial.html

• React Native Community facebook page which is the page where you are supposed to find help and ask question as per react-native site will simply block you if you bring this topic on and will not let you in
• even here on SO, questions like this (after extremely thorough and time consuming research) will earn you only downgrades and zero answers or even attempts
• examples lack clarity and depth of explanation, it seem like whole community follow one pattern, copy / paste demonstrating code-duplication rather than code-sharing
• Most examples cover (to most basic extent) only IOS although most claim cross-platform nature on both Android and IOS with Android being mentioned in the title only and the body covering only IOS
• Impossible to ask for help on react-native site
• Impossible to suggest improvement on react-native site other than create pull request. In other words, they want you to work for them for free
• The framework is cross-platform, that is great but it is more of a copy/paste (copy from IOS into Android, then modify what needs modification) rather than code-sharing strategy. Every example I was able to find and it took me a month, was a violation of DRY principle in its best form

Although I mentioned things that bothered me at most during my research, I have to say that I hope this technology will thrive and become clear open source platform in future. I really like it and hope someone at @Facebook / @ReactNative will consider these suggestions, or at least provide improvements in the documentation, examples, access to community, place to ask questions and get help, clear licensing, ... all of which I was not able to get after spending a month researching RN.

Perhaps the technology is still not mature enough, which makes sense, it is very new.

Would I recommend it?

• To developers yes, definitely. I really like it myself and will spend more time studying it.

• To a company? Not really for the reason explained above.

UPDATES - Getting Better :):

... and to add my 2c to anyone who faced the same problem and contribute to community (at least in terms of finding tutorials that talk about both IOS and Android), I will keep posting links I have managed to find so far:

• https://differential.com/insights/sharing-code-between-android-and-ios-in-react-native/ is very basic example. Not really code sharing but rather code duplication but at least something
• https://www.codementor.io/vijayst/build-react-native-retrofitting-ios-app-to-android-gsf5uyl1q, also more of a code copying rather than code sharing but hey... going somewhere
• https://hackernoon.com/getting-started-with-react-navigation-the-navigation-solution-for-react-native-ea3f4bd786a4 another good one

This document explains that RN philosophy is "learn once, write anywhere" rather than "write once, run anywhere" http://makeitopen.com/tutorials/building-the-f8-app/design/

react-native doesn't export a component named NavigatorAndroid so you are getting undefined instead of a real component.

As you can read in the NavitagorIOS documentation ...

As the name implies, it is only available on iOS. Take a look at React Navigation for a cross-platform solution in JavaScript, or check out either of these components for native solutions: native-navigation, react-native-navigation.