Flutter : "Could not resolved the package" every install new packages

I have some problem about installing new package from pub.dev. I create my own package inside my root project with this command :

flutter create --template=package main_template

structure folder

I installing new package inside main_template not lib. every install new package in main_template i received this error :

 Compiler message: Error: Could not resolve the package 'device_info' in 'package:device_info/device_info.dart'. sinergi_flutter_template/main_template/lib/variable/get_device_id.dart:3:8: Error: Not found: 'package:device_info/device_info.dart' import 'package:device_info/device_info.dart'; ^ sinergi_flutter_template/main_template/lib/variable/get_device_id.dart:9:11: Error: 'DeviceInfoPlugin' isn't a type. final DeviceInfoPlugin deviceInfoPlugin = DeviceInfoPlugin(); ^^^^^^^^^^^^^^^^ sinergi_flutter_template/main_template/lib/variable/get_device_id.dart:9:47: Error: The method 'DeviceInfoPlugin' isn't defined for the class 'GetDeviceId'. - 'GetDeviceId' is from 'package:main_template/variable/get_device_id.dart' ('sinergi_flutter_template/main_template/lib/variable/get_device_id.dart'). Try correcting the name to the name of an existing method, or defining a method named 'DeviceInfoPlugin'. final DeviceInfoPlugin deviceInfoPlugin = DeviceInfoPlugin(); ^^^^^^^^^^^^^^^^ U nhandled exception: FileSystemException(uri=org-dartlang-u ntranslatable-uri:package%3Adevice_info%2Fdevice_info.dart; message=StandardFileSystem only supports file:* and data:* URIs) #0 StandardFileSystem.entityForUri (package:front_end/src/api_prototype/standard_file_system.dart:33:7) #1 asFileUri ( (package:vm/kernel_front_end.dart:604:3) 7) #2 writeDepfile (package:vm/kernel_front_end.dart:799:21) <asynchronous suspension> #3 FrontendCompiler.compile (package:frontend_server/frontend_server.dart:472:15) <asynchronous suspension> #4 _FlutterFrontendCompiler.compile (package:flut ter_frontend_server/server.dart:38:22) #5 starter (package:flutter_frontend_server/server.dart:149:27) #6 main (file:///C:/b/s/w/ir/cache/builder/src/flutter/flutter_frontend_server/bin/starter.dart:8:30) #7 _startIsolate.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:305:32) #8 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:174:12) Target kernel_snapshot failed: Exception: Errors during snapshot creation: null build failed. FAILURE: Build failed with an exception. * Where: Script 'C:\flutter\flutter\packages\flutter_tools\gradle\flutter.gradle' line: 780 * What went wrong: Execution failed for task ':app:compileFlutterBuildDebug'. > Process 'command 'C:\flutter\flutter\bin\flutter.bat'' finished with non-zero exit value 1 * Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights. * Get more help at BUILD FAILED in 20s Gradle task assembleDebug failed with exit code 1 Exited (sigterm) 

Until now i trying install 3 package [Cache Network Image,Device Info , SplashScreen]. And all packages give me that error.

How can i fixed it ?

11 Answers

Are you using vs code?

just restart or close the vs code app (all window), then open it again an run

flutter pub get

This command fixed my issue:

flutter pub get

Are you using Android Studio?

Then just restart it. Worked for me.

Make sure you already have run:

flutter pub get

It's a very annoying issue caused by the pubspec.lock file.

When you add a dependency lower in your package hierarchy you need to confirm it's added to the main app's pubspec.lock file.

It won't be added automatically so:

1. Navigate to the main app's pubspec.lock file folder
2. Run "flutter pub get"
3. Check the pubspec.lock file to confirm your dependency is there
4. If not run "flutter clean" and then repeat step 2

No need to clean the cache or anything :)

try this command

flutter clean

and then pub get

try this command incase if u face any cache related issue

flutter pub cache repair

just run pub get in your main pubspec.yaml file

removing .dart_tool folder in all modules (if you have more than one) helped me

I have the same issue as you. In my case, I have 2 modules (package namely core and shared). In shared modules I add a new package like shimmer and cached_network_image for creating a custom widget. Also, I can import and use that package that I already added in shared modules. But after I running the project, I get the error with information like Could not resolved the package .... So to fix it, I just add shimmer and cached_network_image package into my root project. So for this, I already add 2x package. In shared modules and in the root project. So I think you should do it too if getting that error.

In my case, that requires 2x add new package into pubspec.yml are json_serializable, shimmer, cached_network_image

Not all of it has to be added twice, only those that cause errors are added.

Clean up the cache by flutter pub cache clean

Run pub get for all packages flutter update-packages

remove .idea folder from your project and restart android studio works fine for me

Installing the characters package solved my problem.