ReactNative Firebase Application : Firebase App named ‘[DEFAULT]’ already exists (app/duplicate-app)

If by change you are getting following exception

Firebase App named ‘[DEFAULT]’ already exists (app/duplicate-app)

Then do the following fix :

Check whether firebase is already initialised or not before calling firebase.initializeApp

if (!firebase.apps.length) {
  firebase.initializeApp(firebaseConfig);
}

How to Increase Upload Speed for GoogleCloudStorage in nodejs

Uploading Files to GCP : Google Cloud Storage In Nodejs

const Storage = require('@google-cloud/storage');
const config = require('./gcloudConfig');
const Multer = require('multer');

const CLOUD_BUCKET = config.get('CLOUD_BUCKET');

const storage = Storage({
  projectId: config.get('GCLOUD_PROJECT')
});
const bucket = storage.bucket(CLOUD_BUCKET);

// Returns the public, anonymously accessable URL to a given Cloud Storage
// object.
// The object's ACL has to be set to public read.
// [START public_url]
function getPublicUrl (filename) {
  return `https://storage.googleapis.com/${CLOUD_BUCKET}/${filename}`;
}

// Express middleware that will automatically pass uploads to Cloud Storage.
// req.file is processed and will have two new properties:
// * ``cloudStorageObject`` the object name in cloud storage.
// * ``cloudStoragePublicUrl`` the public url to the object.
// [START process]
function sendUploadToGCS (req, res, next) {
  if (!req.files) {
    return next();
  }
  const data = req.body;
  if (req.files.length === 0) {
    next();
  }
  data.accountNumber = '';
    for (let index = 0; index < req.files.length; index++) {
      const gcsname = `${data.accountNumber}/${Date.now()}${req.files[index].originalname}`;
      const file = bucket.file(gcsname);
      const stream = file.createWriteStream({
        metadata: {
          contentType: req.files[index].mimetype
        },
        resumable: false
      });
      stream.on('error', (err) => {
        req.files[index].cloudStorageError = err;
        next(err);
      });
    //  console.log(' upload in progress for file ', index);
      stream.on('finish', () => {
        req.files[index].cloudStorageObject = gcsname;
        file.makePublic().then(() => {
          req.files[index].cloudStoragePublicUrl = getPublicUrl(gcsname);
          console.log(' upload completed, public url is ', req.files[index].cloudStoragePublicUrl,
                     ' index ', index, ' total count ', req.files.length);
          if (index === (req.files.length - 1)) {
            next();
          }
        });
      });
      stream.end(req.files[index].buffer);
    }
}
// [END process]

// Multer handles parsing multipart/form-data requests.
// This instance is configured to store images in memory.
// This makes it straightforward to upload to Cloud Storage.
// [START multer]

const multer = Multer({
  storage: Multer.MemoryStorage,
  limits: {
    fileSize: 5 * 1024 * 1024 // no larger than 5mb
  }
});
// [END multer]

module.exports = {
  getPublicUrl,
  sendUploadToGCS,
  multer
};

The issue is the upload speed is very slow, finding a way to upload faster to google cloud storage

React Native Crash Undefined is not an object (Evaluating ‘Sn[e]’)

Any one facing react native build issue? I am trying to generate debug build but its crashing when the app is launched . The exception has no useful information. I was facing the same issue with

sudo react-native run-android

But that got resolved after upgrading RN from 0.48 to 0.55(latest Stable Version). But the crash remain same for the apk generated using

sudo gradlew assembleDebug

The crash is similar to https://github.com/facebook/react-native/issues/16745

please see screenshot

ReactNative Undefined Not an object evaluating

Solution: Generating React Native Android Release and Debug Builds

1. If any one facing issue with generating ReactNative android build then do not forget to follow below steps

2. Update your key store details as given here

3. Then explicitly bundle the assets using below command

react-native bundle --platform android --dev false --entry-file index.android.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res/

4. Generate the build using gradle

cd android && ./gradlew assembleRelease

Note: for release build I am facing another issue as follows

Error in Release build :

FAILURE: Build failed with an exception.

* What went wrong:
Failed to capture snapshot of input files for task ‘bundleReleaseJsAndAssets’ property ‘$1’ during up-to-date check.
> Failed to create MD5 hash for file ‘/Development/SourceCode/MobApp/testApp/root-state/sock’.

* Try:
Run with –stacktrace option to get the stack trace. Run with –info or –debug option to get more log output.

* Get more help at https://help.gradle.org

BUILD FAILED in 2s

To generate debug build

cd android && ./gradlew assembleDebug

Credits : SO Post

Google Assistant makes calls: Google’s New Technology Duplex, makes real time call and close the deal.

Google Assistance Calls - Duplex — Google Assistance Calls – Duplex

Google Duplex: An AI System for Accomplishing Real World Tasks Over the Phone

A long-standing goal of human-computer interaction has been to enable people to have a natural conversation with computers, as they would with each other. In recent years, we have witnessed a revolution in the ability of computers to understand and to generate natural speech, especially with the application of deep neural networks (e.g., Google voice search, WaveNet). Still, even with today’s state of the art systems, it is often frustrating having to talk to stilted computerized voices that don’t understand natural language. In particular, automated phone systems are still struggling to recognize simple words and commands. They don’t engage in a conversation flow and force the caller to adjust to the system instead of the system adjusting to the caller.

Reference: GoogleBlogs

React Native react-navigation props.navigation.navigate(“DrawerOpen”) doesn’t work

If you are using react-navigation version “1.0.0-beta.11” then the following apis works fine

props.navigation.navigate('DrawerOpen'); // open drawer
props.navigation.navigate('DrawerClose'); // close drawer

If you are using react-navigation version “2.0.0-rc.9” then following apis works fine

props.navigation.openDrawer();
props.navigation.closeDrawer();
props.navigation.toggleDrawer();

Read More About React-Navigation Package : react-navigation performance issues

Typical React Native Navigation issues people facing for this

navigation.navigate(‘DrawerOpen’) doesn’t work

DrawerToggle not working on Android #2760

Drawer Menu doesn’t work in react-native

React Native react-navigation navigation.navigate.reset doesn’t work

1. If you are using react-navigation version “1.0.0-beta.11” then kindly use the below code to reset navigation stack

const resetAction = NavigationActions.reset({
    index: 0,
    key: null,
    actions: [ NavigationActions.navigate({ routeName: 'Home' }) ],
  });
  navigation.dispatch(resetAction);

//Note key: null is very important here.

Reference: github post by react navigation contributor
2. If you are using react-navigation(v2) version “2.0.0-rc.9” then kindly use the below code to reset navigation stack

const resetAction = StackActions.reset({
    index: 0,
    key: null,
    actions: [ NavigationActions.navigate({ routeName: 'DrawerStack' }) ],
  });
  navigation.dispatch(resetAction);

Read More On React-Navigation : Typical issues of react-navigation

React Native react-navigation performance issue: Optimising performance

Rather than writing a detailed article here, I would like to point out very few performance tuning technique with respect to React Native Navigation using react-navigation package.

1. Few check you have to do before blaming react-navigation library, Check whether are you calling any location api to fetch current location.

If you are fetching current location on component mount or will mount then consider my suggestion , fetch the current location on launch of app and save the location, then onwards use the saved location rather than fetching current location every time.

Find the code here to do so

import { AsyncStorage } from 'react-native';

let instance = null;
class SharedPreferences {

  constructor() {
    if (!instance) {
      instance = this;
    }
    return instance;
  }
  async put(key, val) {
    try {
      await AsyncStorage.setItem(key, val);
    } catch (error) {
      console.error('Unable to save in preferences: ', error);
    }
  }

  async get(key) {
    try {
      return await AsyncStorage.getItem(key);
    } catch (error) {
      console.error('Unable to get from preferences: ', error);
    }
  }

   getMultiple(keys, callback) {
     AsyncStorage.multiGet(keys, (err, stores) => {
       if (!err) {
         const keyVals = {};
         stores.map((result, i, store) => {
           keyVals[`${result[0]}`] = result[1];
         });
         callback(keyVals);
       } else {
         callback([]);
       }
     });
  }
}

const sharedPreference = new SharedPreferences();

export const SHARED_PREFERENCE = {
  accessor: sharedPreference
};

'use strict';

import { SHARED_PREFERENCE } from './SharedPreferences';
import { SHARED_PREFERENCE_KEYS } from './AppConstants';

const defaultLocation = {
  coords: {
    latitude: 12.9833,
    longitude: 77.5833
  }
};

export function getCurrentLocation(navigator, callback) {
  SHARED_PREFERENCE.accessor.get(SHARED_PREFERENCE_KEYS.LAST_SAVED_LOCATION_ID)
  .then(savedLocation => {
    if (savedLocation !== null && savedLocation !== undefined) {
      const location = JSON.parse(savedLocation);
      console.log('Returning Saved Location');
      callback(location);
    } else {
      navigator
      .geolocation.getCurrentPosition(
        (location) => {
          console.log(`Saving Device Current Location due to failed save in last try:
             ${JSON.stringify(location)}`);
          SHARED_PREFERENCE
          .accessor
          .put(LAST_SAVED_LOCATION_ID, JSON.stringify(location));
          callback(location);
        }, (geoError) => {
          callback(defaultLocation);
        },
        { enableHighAccuracy: true, timeout: 20000, maximumAge: 1000 });
    }
  })
  .catch((locationError) => {
    callback(defaultLocation);
  });
}

export function saveCurrentLocation(navigator) {
  navigator
  .geolocation.getCurrentPosition(
    (location) => {
      console.log(`Saving Device Current Location: ${JSON.stringify(location)}`);
      SHARED_PREFERENCE
      .accessor
      .put(LAST_SAVED_LOCATION_ID, JSON.stringify(location));
    }, (geoError) => {
      console.log(`Save Location Failed. ${JSON.stringify(geoError)}`);
    },
    { enableHighAccuracy: true, timeout: 20000, maximumAge: 1000 });
}

2. Use Stateless components than ReactComponents wherever it is possible : Read more about StateLessComponents

3. Upgrade react-navigation package from “1.0.0-beta.11” to “2.0.0-rc.9” : This will boost the performance of react-navigation .

React Native Social Authentication Using Firebase: Google+ and Facebook Signin, Signup – A Step by Step Guide

One has to go through following steps to enable social authentication in their react native mobile apps. In this tutorial we will see how to enable react native social login for android applications.

React Native Google Plus Signup/Signin Using Firebase Authentication

1. Create Project in Google Cloud Platform : Try free trail

2. Enable Google+ API for your project and generate API Key

3. Set YourSHA-1 key and package name (as given in AndroidManifest.xml ) of your android project

To generate your own SHA-1 use the command -> keytool -list -v -keystore mystore.keystore

NOTE : If Your build is debug build then theSHA-1 generated with above command won’t work, kindly check your adb logs carefully, theSHA-1 being used by your android debug build will be logged in the device log. To check device log run the below command from your /Users/<YourSystemUserName>/Library/Android/sdk/platform-tools —> adb logcat

4. Import the same project in firebase

5. Setup android project in your firebase project, then setup authentication methods being used in your app.

6. Then setup sameSHA-1 Key for your firebase project: Navigate to Project setting from side bar and click on general , select android app and set SHA-1 key

NOTE: Once SHA-1 is setup, download google-services.json file in the same page. and keep the file under your android project director app folder /ReactNativeProjectFolder/android/app

Till this your google cloud and firebase setup is done, now we have to do lot of changes in code.

7. add ‘react-native-google-signin’ and ‘firebase’ modules

npm install react-native-google-signin –save

npm install firebase –save

8. Add dependency in your /app/bundle.gradle

Note : in below code those excludes are most important, or else you will encounter strange linking errors.

implementation project(':react-native-google-signin')

if your app is using some other dependencies like react-native-maps or react-native-social-share then do below changes as well

implementation(project(":react-native-google-signin")){
    exclude group: "com.google.android.gms" // very important
}
compile(project(':react-native-maps')) {
      exclude group: 'com.google.android.gms', module: 'play-services-base'
      exclude group: 'com.google.android.gms', module: 'play-services-maps'
    }
implementation 'com.google.android.gms:play-services-base:11.+'
implementation 'com.google.android.gms:play-services-maps:11.+'

9. your android/bundle.gradle file should look as follows

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.0.1'
        classpath 'com.google.gms:google-services:3.0.0' // <--- add this
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        mavenLocal()
        jcenter()
        maven {
            // All of React Native (JS, Obj-C sources, Android binaries) is installed from npm
            url "$rootDir/../node_modules/react-native/android"
        }
    }
}

ext {
    compileSdkVersion   = 23
    targetSdkVersion    = 23
    buildToolsVersion   = "23.0.1"
    googlePlayServicesVersion = "10.2.4"
    androidMapsUtilsVersion = "0.5+"
}

10. run below commands

npm install

react-native link

11. Once you run react native link – check android/settings.gradle file , cross check that there should not be duplicate lines of content.

So far we have done project level configurations, now let us see code changes

12. React Native Google sign-in/sign-up using firebase code

import { GoogleSignin } from 'react-native-google-signin';
import firebase from 'firebase';

function googleAuthConfig(successCallback, failureCallback) {
  /*
   Web Client id 
      Get the client_id from Google-services.json file, in that file under 
    "client": [
       "oauth_client": [
        {
          "client_id": "", //This you have to use as webClientId and the same for android
          "client_type": 3
        }
       
  */
  GoogleSignin.configure({
    iosClientId: CLIENT_IDS.GOOGLE_IOS_CLIENT_ID,
    webClientId: '',
    hostedDomain: '', // specifies a hosted domain restriction
    forceConsentPrompt: true, // [Android] if you want to show the authorization prompt at each login
    accountName: '' // [Android] specifies an account name on the device that should be used
  })
  .then(() => {
    console.log('Google Config Success');
    successCallback();
  })
  .catch((err) => {
    console.log('Google Config Error');
    failureCallback(err);
  });
}


function googleSignin() {
  googleAuthConfig(() => {
      GoogleSignin.signIn()
      .then((user) => {
        const { accessToken } = user;
          var credentials = firebase.auth.GoogleAuthProvider.credential(null, accessToken);
          firebase.auth().signInWithCredential(credentials)
          .then((firebaseResult) => {
            loginToSG(dispatch, firebaseResult, props, 'Google', registerCallback);
          })
          .catch(error => console.log('error while checking with firebase', error));
      })
      .catch((err) => {
        console.log(err);
        });
    }, (googleConfigErr) => {
        console.log(googleConfigErr);
    });
}

13. Finally the most important step is -> once do npm cache clean, delete your existing app from device, delete build folders then run the app

react-native run-android

React Native: Ejecting Expo To Regular React Native Project.

Before explaining the steps for eject from expo, I would like to thank the expo community who has done really a great job, it was nightmare for us to start with ReactNative initially without expo. Expo has done remarkable job and simplified the whole process to us. So we should thank expo community for that. But Expo has come up with its own limitations, it is really difficult to go forward with those limitations, hence ejecting from expo is must.

Follow below steps and find the issues listed in each step and the solutions for the issues faced during eject process. Follow all the below steps

1. npm run eject

? How would you like to eject from create-react-native-app? (Use arrow keys)
❯ React Native: I'd like a regular React Native project. 
  ExpoKit: I'll create or log in with an Expo account to use React Native and the Expo SDK. 
  Cancel: I'll continue with my current project structure. 
Choose 1st option

2. then run the command

react-native run-android
Building and installing the app on the device (cd android && ./gradlew installDebug)…

Problem:
FAILURE: Build failed with an exception.

* What went wrong:
A problem occurred configuring project ‘:app’.
> SDK location not found. Define location with sdk.dir in the local.properties file or with an ANDROID_HOME environment variable.

* Try:
Run with –stacktrace option to get the stack trace. Run with –info or –debug option to get more log output.

BUILD FAILED

Total time: 45.174 secs
Could not install the app on the device, read the error above for details.
Make sure you have an Android emulator running or a device connected and have
set up your Android development environment:
https://facebook.github.io/react-native/docs/android-setup.html

Solution:
Create local.properties in the andoid project folder and save the below content in that
sdk.dir = /Users/USERNAME/Library/Android/sdk
USERNAME: USERNAME should be your maachine user name

3. run the command

$ sudo react-native run-android

Problem:

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ‘:app:installDebug’.
> com.android.builder.testing.api.DeviceException: No connected devices!

* Try:
Run with –stacktrace option to get the stack trace. Run with –info or –debug option to get more log output.

BUILD FAILED

Total time: 6.945 secs
Could not install the app on the device, read the error above for details.
Make sure you have an Android emulator running or a device connected and have
set up your Android development environment:
https://facebook.github.io/react-native/docs/android-setup.html

Solution : Use proper cable and connect your device, enable debug mode in your android device. this is problem with some devices, do not spend time on this, because you will face bigger problems later 🙂 so either change the device or try with different cable.

4. Problem
com.android.ddmlib.InstallException: Failed to install all
at com.android.ddmlib.SplitApkInstaller.install(SplitApkInstaller.java:89)
at com.android.ddmlib.Device.installPackages(Device.java:904)
at com.android.builder.testing.ConnectedDevice.installPackages(ConnectedDevice.java:137)
at com.android.build.gradle.internal.tasks.InstallVariantTask.install(InstallVariantTask.java:134)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:75)
at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.doExecute(AnnotationProcessingTaskFactory.java:228)
at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.execute(AnnotationProcessingTaskFactory.java:221)
at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.execute(AnnotationProcessingTaskFactory.java:210)
at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:621)
at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:604)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:80)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:61)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:46)
at org.gradle.api.internal.tasks.execution.PostExecutionAnalysisTaskExecuter.execute(PostExecutionAnalysisTaskExecuter.java:35)
at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:66)
at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:58)
at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:52)
at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:52)
at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:53)
at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:203)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:185)
at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.processTask(AbstractTaskPlanExecutor.java:66)
at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.run(AbstractTaskPlanExecutor.java:50)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor.process(DefaultTaskPlanExecutor.java:25)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter.execute(DefaultTaskGraphExecuter.java:110)
at org.gradle.execution.SelectedTaskExecutionAction.execute(SelectedTaskExecutionAction.java:37)
at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:37)
at org.gradle.execution.DefaultBuildExecuter.access$000(DefaultBuildExecuter.java:23)
at org.gradle.execution.DefaultBuildExecuter$1.proceed(DefaultBuildExecuter.java:43)
at org.gradle.execution.DryRunBuildExecutionAction.execute(DryRunBuildExecutionAction.java:32)
at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:37)
at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:30)
at org.gradle.initialization.DefaultGradleLauncher$4.run(DefaultGradleLauncher.java:153)
at org.gradle.internal.Factories$1.create(Factories.java:22)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:91)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:53)
at org.gradle.initialization.DefaultGradleLauncher.doBuildStages(DefaultGradleLauncher.java:150)
at org.gradle.initialization.DefaultGradleLauncher.access$200(DefaultGradleLauncher.java:32)
at org.gradle.initialization.DefaultGradleLauncher$1.create(DefaultGradleLauncher.java:98)
at org.gradle.initialization.DefaultGradleLauncher$1.create(DefaultGradleLauncher.java:92)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:91)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:63)
at org.gradle.initialization.DefaultGradleLauncher.doBuild(DefaultGradleLauncher.java:92)
at org.gradle.initialization.DefaultGradleLauncher.run(DefaultGradleLauncher.java:83)
at org.gradle.launcher.exec.InProcessBuildActionExecuter$DefaultBuildController.run(InProcessBuildActionExecuter.java:99)
at org.gradle.tooling.internal.provider.ExecuteBuildActionRunner.run(ExecuteBuildActionRunner.java:28)
at org.gradle.launcher.exec.ChainingBuildActionRunner.run(ChainingBuildActionRunner.java:35)
at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:48)
at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:30)
at org.gradle.launcher.exec.ContinuousBuildActionExecuter.execute(ContinuousBuildActionExecuter.java:81)
at org.gradle.launcher.exec.ContinuousBuildActionExecuter.execute(ContinuousBuildActionExecuter.java:46)
at org.gradle.launcher.exec.DaemonUsageSuggestingBuildActionExecuter.execute(DaemonUsageSuggestingBuildActionExecuter.java:51)
at org.gradle.launcher.exec.DaemonUsageSuggestingBuildActionExecuter.execute(DaemonUsageSuggestingBuildActionExecuter.java:28)
at org.gradle.launcher.cli.RunBuildAction.run(RunBuildAction.java:43)
at org.gradle.internal.Actions$RunnableActionAdapter.execute(Actions.java:173)
at org.gradle.launcher.cli.CommandLineActionFactory$ParseAndBuildAction.execute(CommandLineActionFactory.java:239)
at org.gradle.launcher.cli.CommandLineActionFactory$ParseAndBuildAction.execute(CommandLineActionFactory.java:212)
at org.gradle.launcher.cli.JavaRuntimeValidationAction.execute(JavaRuntimeValidationAction.java:35)
at org.gradle.launcher.cli.JavaRuntimeValidationAction.execute(JavaRuntimeValidationAction.java:24)
at org.gradle.launcher.cli.ExceptionReportingAction.execute(ExceptionReportingAction.java:33)
at org.gradle.launcher.cli.ExceptionReportingAction.execute(ExceptionReportingAction.java:22)
at org.gradle.launcher.cli.CommandLineActionFactory$WithLogging.execute(CommandLineActionFactory.java:205)
at org.gradle.launcher.cli.CommandLineActionFactory$WithLogging.execute(CommandLineActionFactory.java:169)
at org.gradle.launcher.Main.doAction(Main.java:33)
at org.gradle.launcher.bootstrap.EntryPoint.run(EntryPoint.java:45)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.gradle.launcher.bootstrap.ProcessBootstrap.runNoExit(ProcessBootstrap.java:55)
at org.gradle.launcher.bootstrap.ProcessBootstrap.run(ProcessBootstrap.java:36)
at org.gradle.launcher.GradleMain.main(GradleMain.java:23)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.gradle.wrapper.BootstrapMainStarter.start(BootstrapMainStarter.java:30)
at org.gradle.wrapper.WrapperExecutor.execute(WrapperExecutor.java:127)
at org.gradle.wrapper.GradleWrapperMain.main(GradleWrapperMain.java:61)
:app:installDebug FAILED

Solution:
update gradle version in build.gradle file of your android project
classpath ‘com.android.tools.build:gradle:3.0.1’

Problem
Building and installing the app on the device (cd android && ./gradlew installDebug)…

FAILURE: Build failed with an exception.

* What went wrong:
A problem occurred configuring root project ‘testApp’.
> Could not resolve all dependencies for configuration ‘:classpath’.
> Could not find com.android.tools.build:gradle:3.0.1.
Searched in the following locations:
https://jcenter.bintray.com/com/android/tools/build/gradle/3.0.1/gradle-3.0.1.pom
https://jcenter.bintray.com/com/android/tools/build/gradle/3.0.1/gradle-3.0.1.jar
Required by:
:testApp:unspecified

* Try:
Run with –stacktrace option to get the stack trace. Run with –info or –debug option to get more log output.

BUILD FAILED

Total time: 10.721 secs
Could not install the app on the device, read the error above for details.
Make sure you have an Android emulator running or a device connected and have
set up your Android development environment:
https://facebook.github.io/react-native/docs/android-setup.html

Solution:
add google() to your build script, as follows

buildscript {
    repositories {
        google()
        jcenter()
    }

6. Problem

FAILURE: Build failed with an exception.

* Where:
Build file ‘/testapp/android/build.gradle’ line: 5

* What went wrong:
A problem occurred evaluating root project ‘testApp’.
> Could not find method google() for arguments [] on repository container.

* Try:
Run with –stacktrace option to get the stack trace. Run with –info or –debug option to get more log output.

BUILD FAILED

Total time: 1.973 secs
Could not install the app on the device, read the error above for details.
Make sure you have an Android emulator running or a device connected and have
set up your Android development environment:
https://facebook.github.io/react-native/docs/android-setup.html

Solution:
in your android/gradle/wrapper/gradle-wrapper.properties file check whether you have gradle distribution version 4,
it should be as follow.

distributionUrl=https\://services.gradle.org/distributions/gradle-4.1-all.zip

7. After this build success
8. Now facing Run-time exception of something like this

react android run Couldn’t find preset\ babel-preset-react native stage 0

error: bundling failed: “TransformError: D:\\path\\path\\project\\index.android.js: Unex
pected token ) (While processing preset: \”D:\\\\path\\\\path\\\\project\\\\node_modules
\\\\babel-preset-react-native\\\\index.js\”)”

Solution : Remove “babel-preset-react-native-stage-0/decorator-support” from your .bablerc file, Your bablerc file should look as follows

{
  "presets": [
    "react-native"
  ],
  "env": {
    "development": {
      "plugins": [
        "transform-react-jsx-source"
      ]
    }
  }
}

React Native Android Build: Exception After Ejecting(Detaching) Expo with ExpoKit

React Native Android Build: Exception After Ejecting(Detaching) Expo

After so much struggle resolved all the build issues for React Native Android build after ejecting expo but using ExpoKit. Now getting android runtime exception, the app crashes as soon as it is launched. Exception is as follows.

React Native Android Runtime Exception

E/AndroidRuntime(17278): Process: com.company.testapp, PID: 17278
E/AndroidRuntime(17278): java.lang.NoClassDefFoundError: Failed resolution of: Lbolts/AppLinks;
E/AndroidRuntime(17278): 	at com.facebook.appevents.internal.SourceApplicationInfo$Factory.create(SourceApplicationInfo.java:131)
E/AndroidRuntime(17278): 	at com.facebook.appevents.internal.ActivityLifecycleTracker.onActivityCreated(ActivityLifecycleTracker.java:131)
E/AndroidRuntime(17278): 	at com.facebook.appevents.internal.ActivityLifecycleTracker$1.onActivityCreated(ActivityLifecycleTracker.java:77)
E/AndroidRuntime(17278): 	at android.app.Application.dispatchActivityCreated(Application.java:189)
E/AndroidRuntime(17278): 	at android.app.Activity.onCreate(Activity.java:952)
E/AndroidRuntime(17278): 	at android.support.v4.app.SupportActivity.onCreate(SupportActivity.java:66)
E/AndroidRuntime(17278): 	at android.support.v4.app.FragmentActivity.onCreate(FragmentActivity.java:297)
E/AndroidRuntime(17278): 	at host.exp.exponent.experience.ReactNativeActivity.onCreate(ReactNativeActivity.java:130)
E/AndroidRuntime(17278): 	at host.exp.expoview.ExponentActivity.onCreate(ExponentActivity.java:69)
E/AndroidRuntime(17278): 	at android.app.Activity.performCreate(Activity.java:6120)
E/AndroidRuntime(17278): 	at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1112)
E/AndroidRuntime(17278): 	at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2467)
E/AndroidRuntime(17278): 	at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2600)
E/AndroidRuntime(17278): 	at android.app.ActivityThread.access$800(ActivityThread.java:177)
E/AndroidRuntime(17278): 	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1469)
E/AndroidRuntime(17278): 	at android.os.Handler.dispatchMessage(Handler.java:111)
E/AndroidRuntime(17278): 	at android.os.Looper.loop(Looper.java:194)
E/AndroidRuntime(17278): 	at android.app.ActivityThread.main(ActivityThread.java:5622)
E/AndroidRuntime(17278): 	at java.lang.reflect.Method.invoke(Native Method)
E/AndroidRuntime(17278): 	at java.lang.reflect.Method.invoke(Method.java:372)
E/AndroidRuntime(17278): 	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:959)
E/AndroidRuntime(17278): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:754)
E/AndroidRuntime(17278): Caused by: java.lang.ClassNotFoundException: Didn't find class "bolts.AppLinks" on path: DexPathList[[zip file "/data/app/com.company.testapp-1/base.apk"],nativeLibraryDirectories=[/data/app/com.company.testapp-1/lib/arm, /vendor/lib, /system/lib]]
E/AndroidRuntime(17278): 	at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
E/AndroidRuntime(17278): 	at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
E/AndroidRuntime(17278): 	at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
E/AndroidRuntime(17278): 	... 22 more
E/AndroidRuntime(17278): 	Suppressed: java.lang.ClassNotFoundException: bolts.AppLinks
E/AndroidRuntime(17278): 		at java.lang.Class.classForName(Native Method)
E/AndroidRuntime(17278): 		at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
E/AndroidRuntime(17278): 		at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
E/AndroidRuntime(17278): 		at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
E/AndroidRuntime(17278): 		... 23 more
E/AndroidRuntime(17278): 	Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack available
V/SettingsInterface(  765):  from settings cache , name = dropbox:data_app_crash , value = null
V/SettingsInterface(  765):  from settings cache , name = send_action_app_error , value = 1
D/ActivityManager(  765): SVC-mBroadcastQueues: com.android.server.am.BroadcastQueue@29a56dae
D/ActivityManager(  765): SVC-mBroadcastQueues: com.android.server.am.BroadcastQueue@256ee74f
W/ActivityManager(  765):   Force finishing activity 1 com.company.testapp/.MainActivity

Solution

Finding the solution… Will update it soon here.