Android Emulator for react-native expo is not working - react-native

No address associated with host name
Having an issue when try to run my project on android emulator, there is no error in expo cli but project is not running on emulator and it gives error "Unable to resolve host 'exp.host' No address associated with host name"

If your app requires internet connection, and the emulator doesn't have one, then you have to enable it.
In my case, I just cold booted my emulator, and next time I ran, it worked without giving any error.

I got the same error, I fix it, the problem was in Mac OS wifi settings, Im just add in network > advanced settings > DNS > add 2 port, 1 = 8.8.8.8, 2 = 8.8.4.4, then reboot android simulator, and start "Cool Boot Now"

Related

No apps connected. Sending "reload" to all React Native apps failed. Make sure your app is running in the simulator or on a phone connected via USB

React Native app debug on real device has some problems;
My metro bundler console gives warn:
warn No apps connected. Sending "reload" to all React Native apps failed. Make sure your app is running in the simulator or on a phone connected via USB.
warning and that cause real IOS device connection problem.
When I try to reload my react native app from Chrome React Native Debugger, it gives above warning and I can not debug my code from on Chrome
react-native: 0.62.2,
IOS: 13.6
It happens on Real device connection. When I work with IOS simulator, there is not problem.
NOTE: My phone and macbook on SAME wi-fi network.
So problem is not related to different wi-fi network usage.
⚠️ For iOS users :
Check that your build target is Debug :
Xcode Product => Scheme => Edit Scheme => Debug (and not release ! )
⚠️ For Android users :
I have found a solution that I posted on github.
Not the best but it could be useful:
First, you have to open MainApplication.java
and remove import com.facebook.react.BuildConfig;
Next, follow these steps :
# Reset metro bundler cache :
`npx react-native start --reset-cache`
# Remove Android assets cache :
`cd android && ./gradlew clean`
# Relaunch metro server :
`npx react-native run-android`
And see the magic 🎉
See here :
https://github.com/facebook/react-native/issues/29396
Running this worked for me for a Physical Android Device.
adb reverse tcp:8081 tcp:8081
or
npm run android-connect
If you face an error saying 'More than two devices are running', make sure that the emulators like BlueStacks are not running.
Your iPhone has to be connected to the same network (WiFi for example) as your Mac, because they have to communicate with each other (React Native Doc).
If it's already the case, then fill in the DCHP server manually on your iPhone and Mac, using Google's server (8.8.8.8), because it could be due to DHCP problems.
You may need to disconnect and reconnect to your Wifi.
For me I need to set the bundler location in my app from "localhost:8081" to "192.168.1.XX:8081" which is my computer's local IP address where Metro bundler runs on and the port is 8081.
If you don't know which port your bundler runs on you can specify it as a parameter like:
npx react-native start --port 8081
Then you need to specify the location in your development app. To do that:
Shake your device
Click change bundle location (I am on RN 0.64 it may differ in yours)
Give the bundler location of your computer's IP and port where Metro bundler runs on like:
and they started to communicate with each other.
My problem was that I was not connected to the same WiFi on my Mac and Iphone.I turned the wifi off and back on on both devices, and made sure both the mac and Iphone was connected to the same WiFi. Annoying, but true!
Your iPhone & mac must be connected to the same network. If both device connected to same network you must check local network availability for your app. (this happened to me on a iOS 14.0 running device).
check local network - iOS 14
Settings -> Privacy -> Local Network
On Android, this may also happen due to a problem with the network security config. If you do use the network security config, try removing the line android:networkSecurityConfig="#xml/network_security_config" from AndroidManifest.xml
My problem was that the emulator I was using had airplane mode turned on (because I tested related functionality). The problem resolved when I turned it off, thus enabling network to operate as usual.
My problem is that the device is not connected to the internet. Throws the error. Try connecting stable internet connection.
When I remove network_security_config.xml and remove the following:
`android:networkSecurityConfig="#xml/network_security_config"`
It works
I work on IOS environment, testing on an IPad that is USB connected.
I managed to fix this issue by adding the bundler address (127.0.0.1) in the ipad to reconnect
Shake the device (opens react native debug menu) > Configure Bundler > "127.0.0.1" in the first field
Hope this helps someone !
What did the trick for me was the following:
In Xcode go to Debug/Detach from YourAppName
Then reattach it by going to Debug/Attach to Process, select your app from the list (usually the first entry at the top).
I tried everything and after running
adb reverse tcp:8081 tcp:8081
yarn android
it worked.
What worked for me in this scenario was these steps
run server with --reset-cache
run npx jetify
open the project in adroid studio
go to refactor -> Migrate to AndroidX (this was the step that i was missing earlier)
start your emulator
run the app from android studio and it should work
Sometimes it's a firewall / router issue - see if that's your problem:
Find out the local IP address of your computer (where your Metro bundler / server is running).
Open a browser from your phone.
Open the IP address from #1 with port 8081 (e.g. http://192.168.0.42:8081).
If it's not loading -> it's a firewall / router issue.
A simple solution would be to connect the computer to the phone's hotspot.
yarn start web
you can use this command to scan the QR code and see the app in you EXPO app at you mobile
You musk permit local network in the application setting in iOS. Otherwise, Metro can not find your app even in the same network.
For iOS on Xcode:
Go to Window > Devices and Simulators, Go to "Installed Apps" section, Click on +, Pick your app , Run your code.
(This issue happened to me when I run the app after I uninstalled it from the device)
For me the solution was to remove the installed app and build run in Xcode again.
Oh, I had the same problem with RN - for me - there was a problem with connecting iphone to macbook server on localhost - and it solved if I just turned off wifi on macbook and then turned it on again. (Yes, it sounds weird - but it's a common problem)
For me, on IOS, Xcode would be stuck in debugging, a breakpoint is active and Metro can't reload because no apps are connected. To solve this:
open Xcode
In the left-hand side panel, click from the top row on Debug navigator (if it's not already focused and in the view like it was for me)
In the bottom pane (which can be minimized fully, in which case you have to hold and drag from the bottom of Xcode to expand it into view) you see a set of debugging buttons, the most left
one is a blue arrow-head-shaped button that continues/unpauses the script, click it.
after unpausing the script my app would connect to Metro.
Easy solution ->
1- Go to Developer options of your phone .
2- Disable adb authorization timeout..
Now reload project and enjoy coding..
My problem was that i added --variant=release
npx react-native run-android --variant=release
So i remove it and worked for me.Like this:
npx react-native run-android

Error in reloading the application react native

i'm new in react native whenever i'm trying to reload the application i'm getting error on my emulator screen i.e could not connect to development server.i'm getting below error. Any help will be appreciated.
Try to open in your device browser the url: http://10.0.2.2:8081/index.delta (if it is responding go to step 2 - even with errors - if not go to 3).
Add the following line to your androidManifest.xml Application tag:
android:usesCleartextTraffic="true", rebuild your native app and test.
In a terminal run this command: adb reverse tcp:8081 tcp:8081
i had this problem too.
follow these steps in order
1.
try deleting your emulator and create a new one
then restart your pc
start react native & run android
if not solved
2.
connect an android phone via USB to your pc
turn on USB Debugging at your phone's setting
now start react native & run android

emulator-5554 unauthorized for adb devices

I'm trying to get my react-native project to run on an android emulator while on a Mac operating system. It worked fine on my windows.
On my Mac, I go to terminal and type react-native run-android and I get the error message:
$ react-native run-android
Scanning 616 folders for symlinks in /Users/John/Documents/myreactnativeproject/node_modules (17ms)
Starting JS server...
Building and installing the app on the device (cd android && ./gradlew installDebug)...
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
I type adb devices and I see
List of devices attached
emulator-5554 unauthorized
I go into the settings of my android emulator, I go to Settings Build Number to tap it several times to enable Developer options. In developer options, I enabled USB debugging, disabled Verify apps over USB, and left everything else as default. I shut down my android studio and emulator, restarted it. But still, the same issues mentioned above.
What am I doing wrong?
EDIT
I just connected my android phone to my Mac. When I run adb devices, I see this result
List of devices attached
YLEDU16B18004313 device
But when I run react-native run-android, I get the same error as above. So maybe there is something wrong with my react-native set up instead?
EDIT 2
I was able to deploy the app to my android phone by adding these extra steps
chmod 755 android/gradlew
For some reason, when I type echo $ANDROID_HOME into the terminal, I get the result /Users/John/Library/Android/sdk. But if I add the echo $ANDROID_HOME line to my android/gradlew file, it echoes nothing. And when I run the react-native run-android command, the compiler complains that ANDROID_HOME is not defined. So I have to type export ANDROID_HOME=/Users/John/Library/Android/sdk again, then running the react-native run-android command works and deploys it to my phone.
However, my emulator still doesn't work. The new error message I get is that Skipping device 'emulator-5554' (emulator-5554): Device is UNAUTHORIZED,.
But at least I have a temporary solution, and to debug with my phone.
EDIT 3
I got rid of the emulator 5554 unauthorized error by going into my Android Virtual Devices and deleting the virtual device. Then I re-installed it. And now my adb devices shows emulator 5554 device. And I am not able to deploy the app to my emulator.
In my case, Create a Virtual Device with Google APIs Image, not Google Play Image worked for me.
The problem occurs the only emulator that runs on Android Pie others don't.
In Android Studio
Open an Android Virtual Device Manager.
Create a new Virtual Device.
Select any Hardware you want.
Select any System Image which the Target is "(Google APIs)" not "(Google Play)" (If you don't found. Try to look at "x86 Images" tab or "Other Images" tab)
Done!
Android emulators have by default "Usb Debugging" in settings. You just need to wipe the data of the emulator. Do the following steps. It will work :---
Close the emulator and run the command adb kill-server in the command prompt. If adb is not set in you path then you might run this command from directory where adb is present.
Click on Wipe Data option from avd Actions menu.
Now run the emulator. It should work.
create new Virtual Device, and make sure you choose Google API's.
run the new device!. this should work
In my case, following steps worked
Wipe data from avd manager
Cold boot now
I managed to authenticate the adb on a Pixel 2, Android 9.0 (Google Play), API 28, x86_64 virtual device (Intel HAXM). The problem should be related to the Extended Controls (the 3 dots bottom icon menu, when the virtual device is booted), the Google Play menu, that is checking the version of the Google Play services. When adb is not 'unauthorized', this page is displaying the correct version, and the Update button opens inside the phone the Play Store with the Play Services app, so you can update it.
The steps I took to be able to authenticate are:
Make sure the USB debugging is turned ON in Dev setting
Revoke the USB debugging authorizations
Make sure the Extended Controls > Settings > Advanced > Open GL options are set to the: 'Desktop native OpenGL' and 'Renderer maximum (up to OpenGL ES 3.1)', so the emulator interface, animations, etc, are fast!
Power off the emulator
In 'Your Virtual Devices' in Android Studio, click the down arrow in Actions > Select 'Cold Boot Now'
When the device boot, you have to be fast, the dialog to remember and accept the USB connection will show and disappear for like less than 1 second (again I guess related to some automation scripts kicking, idn).
If you manage to click the 'remember' and 'ok' checkbox and button before the dialog disappears, you are done. Else you have to Power Off and Cold Boot again.
After that, don't wipe your emulator, else you'll have to do that insane race clicking again!
I run adb kill-server and adb devices.
the device will back again.
for Emulator, the default settings is debug enabled
Creating an emulator with graphics set to "Software - GLES 2.0" worked for me (Nexus 6 image).
I was initially using a Nexus 5X image which didn't allow me to select the graphics option.
NOTE: I went through the steps mentioned in EDIT 2 and EDIT 3 by the OP before doing this.
This can happen if USB debugging is not enabled on the emulator device.
Go to the emulated device, enable the Developer options and enable USB debugging.
I had to create a new emulator with Google Api. Wiping data didn't work for me.
2022 answer
What a shame of thread: so many "answers", comments and upvotes and none worked. Nobody simply mentioned that the "adb unauthorized" is caused by the adb keys stored in ~/.android/adbkey and ~/.android/adbkey.pub After deleting and recreating them, the problem was solved.
Credit: Android Emulator Unauthorized
I got my mac system to deploy a react-native build to my physical phone by following Edit 2 in the question.
I got my mac system to deploy a react-native build to my emulator by following Edit 3 in the question.
I think the issue was generally caused by moving my project from a Windows dev area to Mac dev area. Then probably a combination of different issues happened that cause builds to fail for each situation.
Deleting emulator and creating it again helped me on Ubuntu
I solved Problem
add ANDROID_SDK_HOME to environment variable
ANDROID_SDK_HOME = D:\sdk
and unplug device
and use new cmd

How to run React Native app on Android Phone

I am building React Native app.
It is working well when I launch the app in terminal on Mac using "react-native run-android".
But when I got the apk file and installed it on another android device manually, it does not work.
It looks like this.
If you are connected via cable, do the following:
1. Goto > Settings > About Device
2. Then Software Info
3. Then > Build Number
4. Now Tap (Click) multiple times on Build Number to Enable Developer Options
5. Here you go not the Developer Options will be visible in your Settings
6. Now Go inside the Developer Options and Enable USB Debugging Mode.
7. Open your terminal
On Windows open Android SDK Manger > Platform Tools
Type:
$ adb devices
This will show you the devices and simulator/virtual-devices that you have on you computer.
8. Forward requests from your device
Type:
$ adb reverse tcp:8081 tcp:8081
9. Run it
Type:
$ npm run android
The app should appear on your device
Looks like the source code in your APK is looking for the package server.
Read this on how to build APKs for react-native: React-Native - Generating Signed APK
If your devices is connected via cable:
If you're on a physical device connected to the same machine, run 'adb reverse tcp:8081 tcp:8081' to forward requests from your device
Otherwise, you can still do this via Wifi by following the last point in the error:
If your device is on the same Wi-Fi network, set 'Debug server host & port for device' in 'Dev settings' to your machine's IP address and
the port of the local dev server -e.g. 10.0.1.1:8081
Please find the below steps to run react-native code on a physical mobile device:-
Please make sure you are on the same wifi network(Mobile and Laptop).
Run your code and install it on the mobile through the Android Studio.
The app will install and asking you to change your "dev settings".
Shake your phone and go to "dev settings" and type your machine's IP address(192.16.XX.XXX:8081).
Close the app once and open again, in the terminal you will see like this
6. wait for a minute app will install and reflect the changes.
Get a list of all the devices:
adb devices
Then set the which device to run on:
adb -s <device name> reverse tcp:8081 tcp:8081
Then deploy the app:
react-native run-android
If you've upgraded your version of react-native since generating your android project files, you might want to regenerate those now. I think you can use react-native upgrade.
The following are required in order to run a React Native app on Android:
Android Studio
Android SDK
JDK 8 (installation instructions for macOS here and Windows here)
Answer Source: Make An App
We can run the React Native app on Android platform by running the following code in the terminal.
react-native run-android
Before you can run your app on Android device, you need to enable USB Debugging inside the Developer Options.
If you get a “bridge configuration isn’t available” error. Then use below command to solve
adb -s tcp:8081 tcp:8081
Now re-run the app using
react-native run-android
The command for correcting networking on the physical device should instead be:
adb -s reverse tcp:8081 tcp:8081
When USB Debugging is enabled, you can plug in your device and run the code snippet given above.
Configure your app to connect to the local dev server via Wi-Fi
Make sure your laptop and your phone are on the same Wi-Fi network.
Open your React Native app on your device. You can do this the same
way you'd open any other app. You'll see a red screen with an error.
This is OK. The following steps will fix that. Open the Developer
Go to Dev Settings. Go to Debug server host for device. Type in your machine's IP address and the port of the
local dev server (e.g. 10.0.1.1:8081).
On Mac, you can find the IP address in System Preferences / Network. On Windows, open the command
prompt and type ipconfig to find your machine's IP address (more
info).
Go back to the Developer menu and select Reload JS.
The Native Android emulator is slow. We recommend downloading Genymotion for testing your app.
The developer menu can be accessed by pressing command + M.

ReactNative custom port support for run-android command, McAfee workaround

I am trying to configure react native for windows for android app development but I am unable to use port 8081 as it is used by McAfee agent on my laptop.
I am able to start node js server on different port (8090)
react-native start --port=8090
But when I run the command:
react-native run-android
I am unable to specify port option. Looks to be that it is hardcoded with 8081.
Is there anyway I can start react-native run-android for custom port(8090) port on windows?
I am completely new to reactnative and following below link to configure sample Awesomeproject for android on windows.
https://facebook.github.io/react-native/docs/getting-started.html#content
There is a small work around for this. Anyone running this on a physical device(or even otherwise) can restart their adb session using a different port.
eg.
react-native start --port=1234
On a different cmd/terminal window.
react-native run-android
After which I am greeted by these messages.
BUILD SUCCESSFUL
Total time: 22.589 secs
Running C:\SDK/platform-tools/adb -s VY0025160560725694 reverse tcp:8081
tcp:8081
This runs it on default reverse port of 8081, which is blocked by McAfee.
Work around:
adb reverse tcp:8081 tcp:1234
Note: You may have to kill and re-open the app.
Currently I am unable to provide an answer for an emulated device since I do not have one installed on my system. But the steps should be similar.
Was setting up RN with android emulator. Had the same problem with company's laptop with McAfee installed and 8081 port occupied. 3 things i did to make it work.
run the packager server in a different port as you mentioned above, like 8090 port: react-native start --port=8090.
i use android emulator(VD), so i need to change the VD's debug server by: cmd+M in the emulator, Go to Dev Settings → Debug server host for device, enter ‘localhost:8081’. If you connect a real android device, this step may be skipped.
Last thing to do is to forward the request in our local VD’s 8081 port to our machine’s 8090 port which runs the packager server by doing: adb reverse tcp:8081 tcp:8090
More about adb reverse.
Now you should be able to change your index.android.js and hit r twice or cmd+M -> Reload to reload the VD.
I found a workaround that works (I am on Linux, but it should work on Windows also).
In a Terminal tab, from the project root, I run :
react-native start --port=8082
This kicks Node up on port 8082.
Then, I launch the app using :
react-native run-android
Once the app is launched, I update the development server's url and port to match the settings above (Cf. this answer if you don't know how).
It works !!
Finally It Worked! I also faced the same issue where my 8081 port was being used by McAfee and after reading and trying all the solution only the following steps worked for me where I able to run my project on 8088
Steps :
1. react-native init myproject(create myproject using react-native cli) then cd myproject(move to myproject)
2. open android studio - ctrl + R => Replace 8081 to 8088 from every file.
3. react-native run-android(simulator should be running).
4. Check your local IP ex : ipconfig in windows will give your IP
5. Check yourIP:8088 in your browser => It wil show(React Native packager is running.)
6. At this time in your simulator you will get 403 forbidden error or package manager not running error
7. Ok, Now you need to point your simulator to 8088 instead of 8081, So on your simulator type cntrl + m => Dev settings => Debugging => Set IP eg : yourIP:8080
8. Now stop package manager.
9. Now remove .babelsrc from your project.
10. Rerun the react-native run-android(If everything goes fine it will work).
I know its not the best way to solve this problem but until facebook team is not giving any better solution for it this may be a good approach since 8081 is hard coded everywhere.
Note : In some cases I have seen white screen comes without any error. For this issue please make sure that you have removed initially generated .babelsrc.
and stop server and restart should solve this issue.
For this
react-native start --port=1234
U just need to do this
react-native run-android --port=1234
That's it, worked for me.
update port for both commands, they should be same.
This is not currently supported, but there appears to be an active and open issue regarding this as well, but unfortunately the core team hasn't had a chance to merge in the PR...
https://github.com/facebook/react-native/issues/1429
This has also been reported on Product Pains, so be sure to up-vote it there...
https://productpains.com/post/react-native/allow-packager-port-to-be-configurable-change-from-8081/
Right now, it may be easier to change the port McAfee runs on. Sorry