When I run "react-native run-android",it gives me error:"could not connect to development server...".-- The red screen
OS: Windows 7
node version:8.2.1
npm version:4.1.2
react-native version:0.47.1
react-native-cli version:2.0.1
android device and emulator version: 5.1.1
i followed following command:
react-native init ProjectName
cd ProjectName
react-native run-android
And this makes the package server run automatically.
But I am not able to access the package server from browser on the machine and the mobile.
My android device connected to computer has debugging enabled i checked it using adb devices command.
Usb debug is on.
I tried running the project on real device and on emulator. On Both I got error: "Unable to load script from assets 'index.android.bundle' Make sure your bundle is packaged correctly or you're running a package server'.
reloading i get the error: "Could not connect to development server."
Then i set the host and port number on development setting on both and got the error "Could not connect to development server."
enter image description here
So how to fix the red error screen issue?Any suggestion is appreciated!
Try to open this link in browser. It will automatically bundle the assets.
http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false
You development server should be running while running this command.
Related
My React-Native(0.68.1) project runs properly on my emulator when using npx react-native run-android command and everything works fine with the metro bundler instance created by this command.
Only when I run project from android studio (2021.3.1 Patch 1) , app is build successfully and installed on emulator, but cannot connect to metro bundler (which I separately run using npx react-native start command).
I wanted to try and update the debug server & port as mentioned in other similar questions , but I cannot access the debug app menu even after dismissing the error (menu doesn't show when ipress the shortcut)
Issue also occurs on build installed on emulator via npx react-native run-android when I close the app and metro bundler created by the command and start a separate metro bundler. In this case but I am able to enter settings menu and enter "debug server and port " to 10.0.2.2:8081 and app connects to metro.
I am using mac mini m1.
To fix this issue
first of all, start your emulator and run adb reverse tcp:8081 tcp:8081 this command on the terminal and then run npx react-native start and then run your project in the android studio and it will automatically link your app to that bundle
I was able to build app using expo build:android previously. However, after upgrading to latest expo version I get following error:
connect ECONNREFUSED 127.0.0.1:19001
Set EXPO_DEBUG=true in your env to view the stack trace.
I also see the following lines in the log:
Publishing to channel 'default'...
Building iOS bundle
I don't added ios to my app.json, I only need to build an android apk. To do that I use expo build:android -t app-bundle
I also removed package-lock.json and node_modules and run npm install, but I get the same error.
I run expo start on another cmd and then run expo build:android -t app-bundle still get same error
Also when I clear expo cache, see the following log:
Restarting Metro Bundler...
Starting Metro Bundler on port 19001.
Couldn't adb reverse: adb.exe: error: Invalid source port: 'undefined'
I had faced same issue myself and found the solution. Expo is looking for localhost:19001 which is not running. Just follow following steps and it should work as expected:
Run expo start no terminal and once it opens up the
browser where you will find this line written Starting Metro
Bundler on port 19001.
Now open another terminal instance and run expo build:android.
I've been looking for a solution to this issue for a day now but couldn't fix it.
I have not used react native for a month when everything was working fine.
Now, if I try to run an existing project that used to work (react native 0.59.5) or a brand new project (react native 0.59.9) with the iOS simulator on my mac, I get the error:
Failed to load bundle - Could not connect to development server
Any idea how I can fix this?
Ok found the issue. Was thinking it might be watchman related issue and wanted to use the command brew reinstall watchmanto reinstall it. By running this command, I found an error
Error: Xcode alone is not sufficient on Mojave. Install the Command Line Tools: xcode-select --install
Looks like the command line tools for xCode was not available anymore.
I launched the command xcode-select --install and then reinstalled watchman just in case. It is now working!
Couldn't connect to development server error
This error is received when the metro bundler isn't running in port 8081. To start the bundler, from project folder run:
npm start
Now, try reloading your app (ctrl + R for iOS / r+r for Android).
Also, check your terminal in case the project failed initial build due to some error.
I create an application with react-native-cli, how can I install it to my Android phone?
(Although in development mode)
Platform: osX(10.12+)
target deployment: Android Phone (v6.0+)
There is an easy way with Terminal.
in development mode, we run application in android studio emulator or expo or gnymotion with a simple command:
react-native run-android
this time before running this command, run:
adb devices
this command will return all of the devices(include android studio emulator) with an id and name.
first, active: USB debugging option in your android phone
then connect your phone to the computer with USB cable
now run adb devices on the terminal.
note that react-native run-android command will install your application on one device that exists in adb devices list.
so close all other android emulator and then run again adb devices for checking all devices connected to this computer.
now simply run below command and wait for installing it on the device.
react-native run-android
this will install the application on your connected phone.
I am working on react native project.
It worked well before I reinstall computer OS.
Now if I run expo start it just show this.
Starting Metro Bundler on port 19001.
This takes forever.
If I run android emulator here, then this error appears.
Couldn't start project on Android: could not install *smartsocket* listener:
cannot bind to 127.0.0.1:5037: Only one usage of each socket address
(protocol/network address/port) is normally permitted. (10048)
could not read ok from ADB Server
* failed to start daemon *
error: cannot connect to daemon
What's wrong here? I am using Genymotion simulator.
I solved this.
I just set path environment to genymotion adb tool directory.
C:\Program Files\Genymobile\Genymotion\tools
And now it works well.
Thanks.