Develop Reference

Why does React Native app crash when clicking on debug in Android emulator?

React Native app shows error when clicked on debug in Android emulator
Attempt to invoke interface method java.lang.String com.facebook.react.bridge.Cat alystInstance.getSourceURL('on a null object reference
below are error screenshots
Emulator screenshot:
Debugger screenshot:
When clicked on reload app crashes and lost connection to debugger.
Tried uninstalling and reinstalling apk in emulator and cd android ./gradlew clean.
Still same error.

I have faced same issue and it was due to the 'react-native-reanimated' package (It's mentioned in their documentation that remote debugging is no longer possible for react-native-reanimated : React Native Reanimated Known problems and limitations) and the solution is to use flipper to debug : Debugging React Native apps with Flipper

How to generate apk of react native app without Android Studio

I have developed a react native app without installing Android Studio. Though I have installed some tools which were absolutely needed for the development.
My Android folder structure is something like this:
Android
.temp
build-tools
cmdline-tools
emulator
licences
patcher
platforms
platform-tools
tools
.knownPackages
Now that I have completed making my app with react native, I want to build an apk (valid and signed) of that and upload it to google drive as of now and share it with my friends, But the problem is, my potato cannot support Android Studio
I could have used expo, but everyone who wants to install my app will have to install expo client app first which is a problem
I hope my sisters and brothers will help me, I am completely new to android-development.
Thanks.
EDIT:-
I was using a real android device for development till now

This solution is for React-Native CLI , don't know it will work with EXPO.
first generate keystore file using in terminal go to java bin folder and then run this
keytool -genkeypair -v -keystore my-upload-key.keystore -alias my-key-alias -keyalg RSA -keysize 2048 -validity 10000
after that paste that generated keystore file in your android app folder
after that you have to add configuration in your gradlw.properties file
MYAPP_UPLOAD_STORE_FILE=my-upload-key.keystore
MYAPP_UPLOAD_KEY_ALIAS=my-key-alias
MYAPP_UPLOAD_STORE_PASSWORD=*****
MYAPP_UPLOAD_KEY_PASSWORD=*****
and also change in app/build.gradle file :
...
android {
...
defaultConfig { ... }
signingConfigs {
release {
if (project.hasProperty('MYAPP_UPLOAD_STORE_FILE')) {
storeFile file(MYAPP_UPLOAD_STORE_FILE)
storePassword MYAPP_UPLOAD_STORE_PASSWORD
keyAlias MYAPP_UPLOAD_KEY_ALIAS
keyPassword MYAPP_UPLOAD_KEY_PASSWORD
}
}
}
buildTypes {
release {
...
signingConfig signingConfigs.release
}
}
}
...
then
$ cd android
$ ./gradlew bundleRelease
for better guidence visit :
https://reactnative.dev/docs/signed-apk-android

If you are using Expo managed flow then you dont need any IDE for build creation, not even macOS machine for ipa, just couple of commands and your build will be ready in 30 min depending upon queue on turtle server.
If you are working with bareflow or React CLI then. you will. be needing assistance of IDE for build creation of both platforms and mac machine for iOS.
For help on commands for build creation on expo managed flow, use this link
Creating android build from Android studio, you can take help from here
Regarding your concern related to build sharing, expo gives you a link from where people can download the APK or IPA. That would ease out the problem related to build sharing

Failed to launch emulator. Reason: No emulators found as an output of `emulator -list-avds`. , Failed to install the app

enter image description here
Im new to React-Native and this is driving me insane, I just want to launch the project in the and view the project in the emulator so I can just start coding, I have tried downloading the latest version of JDK, which is apparently not even needed since android studio comes bundled with its own version & also how do I know what version of JDK my android studio comes bundled with ?
I have been trying to fix this for days now, I even got Blue screen of death when after I messed around with the enviroment variables so now I am desperate and want someone to point me in the right direction.

React native install app on a single running device. Make sure your emulator is in running condition
check all connected devices which are eligible for installing using a command
adb devices
one device at a time

Please check your JDK path for android and ios, if all things are correct the see the project files in the project.
Then run your project.
I hope it runs.

Adding Cordova Platforms

Hey, Guys! I recently started to work with Cordova and when I run the Cordova platform add android i get the following error. I have successfully placed the environment variables for Java and for the Android SDK as well. But the npm modules does not exist in C:/Windows/System32/npm as shown in the error, It is in the Users/My username/AppData/Roaming/npm folder. Some guidance would be appreciated.
I followed the following scripts which are shown in the official Cordova documentation to create a new project.
Cordova create hello com.example.hello HelloWorld
cd hello
Cordova platform add android -> where I'm stuck at

Kindly Check the Android Version Provided by Cordova and verify with your current Android version installed on your system , if there a mismatch :
1) Update Android Version From Android Studio SDK Manager
2) Update Cordova Platform - Refer: Cordova Documentation
External Source
cordova - Error: Failed to fetch platform android

I figured out halfway what the the problem was. There was a file named 'npm' in my C:/Windows/System32 directory wich was of 0kb size, and once i deleted it, the error vanished. But not all the way though. I was able to install the browser platform but not the android platform via cordova platform add android or even specifying what the matching cordova-andriod pluggin to be with cordova platform add andriod#version.
Only through the cordova platform add https://github.com/apache/cordova-android.git script I could install the andriod platform and once it was done other steps worked fine, and the project ran through the Android AVD. Any idea why the normal command to add the android platform didnt work, Just want to know but if it happens again i think Im gonna have to run the get from git command again. Thanks

CodePush react-native ios failed

I am trying to release the React-Native iOS application using Microsoft's Codepush on staging. For this I followed the given instructions on the website and was able to build the bundle file and release successfully on staging but I didn't see the updated changes on mobile which I released.
Firstly I installed the application on mobile using usb (Run on device).
After that I made some changes in my application and released on staging using codepush but when I restarted the app on mobile, it's not showing the changes.
iOS Setup
version: 1.0.0
react-native: 0.17.0
react-native-code-push: 1.5.3-beta
react-native bundle --platform ios --entry-file index.ios.js --bundle-output codepush.js --dev false
code-push release AwesomeProject codepush.js 1.0.0
Can any one help please ? Thanks.

The workflow steps that you posted look correct, so I'm not entirely sure what the issue could be without seeing the logs generated by the CodePush plugin when running your app. If you take a look at our troubleshooting docs, it explains how to examine the logs, along with some common issues and workarounds.
One potential issue is that you're not calling "sync" within the componentDidMount of your root component, and therefore, the plugin thinks your update failed, and rolled it backed. To fix this you simply need to call "CodePush.notifyApplicationReady" in your root component's componentDidMount to notify the CodePush runtime that the update should be considered successful.