A problem occurred evaluating project ':app'. > path may not be null or empty string. path='null'

Question

Iam facing error while iam trying to run flutter.

 D:\fluttapp\testbuild>flutter run
Launching lib/main.dart on Google Pixel 2 XL in debug mode...
Initializing gradle...                                       2.1s
Resolving dependencies...
* Error running Gradle:
ProcessException: Process "D:\fluttapp\testbuild\android\gradlew.bat" exited abnormally:

FAILURE: Build failed with an exception.

* Where:
Build file 'D:\fluttapp\testbuild\android\app\build.gradle' line: 57

* What went wrong:
A problem occurred evaluating project ':app'.
> path may not be null or empty string. path='null'

* 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 https://help.gradle.org

BUILD FAILED in 6s
  Command: D:\fluttapp\testbuild\android\gradlew.bat app:properties


Please review your Gradle project setup in the android/ folder.

D:\fluttapp\testbuild>flutter doctor -v
[√] Flutter (Channel beta, v1.1.8, on Microsoft Windows [Version 10.0.17134.556], locale
    en-IN)
    • Flutter version 1.1.8 at D:\flutter
    • Framework revision 985ccb6d14 (3 weeks ago), 2019-01-08 13:45:55 -0800
    • Engine revision 7112b72cc2
    • Dart version 2.1.1 (build 2.1.1-dev.0.1 ec86471ccc)

[√] Android toolchain - develop for Android devices (Android SDK version 28.0.3)
    • Android SDK at D:\Users\Bhanu\AppData\Local
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-28, build-tools 28.0.3
    • ANDROID_HOME = D:\Users\Bhanu\AppData\Local
    • Java binary at: D:\Program Files\Android\Android Studio\jre\bin\java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b02)
    • All Android licenses accepted.

[√] Android Studio (version 3.1)
    • Android Studio at D:\Program Files\Android\Android Studio
    • Flutter plugin version 29.0.1
    • Dart plugin version 173.4700
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b02)

[√] Connected device (1 available)
    • Google Pixel 2 XL • 192.168.50.101:5555 • android-x86 • Android 9 (API 28)

• No issues found!

I have add repo here. I have taken sample code to make release app version but unable to generate them. Key store is created and add to code repo

https://github.com/bhanu888/buildapk

Answer 1

For me it was a pathing problem.

I was following the flutter guide https://flutter.io/docs/deployment/android

Create a file named <app dir>/android/key.properties that contains a reference to your keystore:

For some reason I (wrongfully) placed my "key.properties" in the app_dir/android/app folder, and this gave me the error.

* What went wrong:
A problem occurred evaluating project ':app'.
> path may not be null or empty string. path='null'

So check your pathing, and where your files are located :)

Bonus info: What helped med was checking the "gradle.build" file with different settings, and it was always the storeFile file(keystoreProperties['storeFile']) that gave me problems. Try commenting it out, or change it to:

storeFile file("key.jks")  

If this works, you know that you have the correct path to your "key.jks" file. Then try introducing the poperties file (keystoreProperties) Like

storeFile file(keystoreProperties['storeFile']) 

This did not work at first, but it does now :)

So check again that you "key.jks" and "key.properties" files are located the "correct" places, and how you point to them.

Answer 2

If you downloaded the app from github, it is possible that signing configs are note adapted. Try like this to comment code on android/app/build.gradle :

    /*signingConfigs {
    release {
  keyAlias keystoreProperties['keyAlias']
        keyPassword keystoreProperties['keyPassword']
        storeFile file(keystoreProperties['storeFile'])
        storePassword keystoreProperties['storePassword']
    }
}
buildTypes {
    release {
        // TODO: Add your own signing config for the release build.
        // Signing with the debug keys for now, so `flutter run --release` works.
        signingConfig signingConfigs.release
    }
   */`

Solution find on : https://github.com/transistorsoft/flutter_background_geolocation/issues/18