[SOLVED] flutter_osm_plugin not working (Expecting an argument)

If you are here it means that you cannot use the OSM plugin for Flutter. And if you are reading this post I hope you’re going to fix it.

This is the error:

e: /home/edoardo/.pub-cache/hosted/pub.dartlang.org/flutter_osm_plugin-0.15.0/android/src/main/kotlin/hamza/dali/flutter_osm_plugin/FlutterInfoWindow.kt: (42, 56): Expecting an argument
e: /home/edoardo/.pub-cache/hosted/pub.dartlang.org/flutter_osm_plugin-0.15.0/android/src/main/kotlin/hamza/dali/flutter_osm_plugin/FlutterOsmPlugin.kt: (60, 53): Expecting an argument
e: /home/edoardo/.pub-cache/hosted/pub.dartlang.org/flutter_osm_plugin-0.15.0/android/src/main/kotlin/hamza/dali/flutter_osm_plugin/FlutterOsmPlugin.kt: (61, 23): Expecting an argument
e: /home/edoardo/.pub-cache/hosted/pub.dartlang.org/flutter_osm_plugin-0.15.0/android/src/main/kotlin/hamza/dali/flutter_osm_plugin/FlutterOsmPlugin.kt: (91, 34): Expecting an argument
........

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':flutter_osm_plugin:kaptGenerateStubsDebugKotlin'.
> Compilation error. See log for more details

* 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 27s
Exception: Gradle task assembleDebug failed with exit code 1

If you are facing the same error, you can try to fix in this way:

• invalidate cache and restart
• upgrade Flutter
• upgrade Android Studio plugins
• upgrade Kotlin version

How to invalidate cache and restart

File -> Invalidate cache/restart

How to upgrade Flutter

From the terminal type:

$ flutter upgrade

How to upgrade Android Studio Plugins

File -> Settings -> Plugins and update what the IDE is suggesting you, then restart Android Studio.

How to upgrade Kotlin version in Gradle

Under project/android/build.gradle find the buildscript{} method and update the Kotlin version like the following example:

buildscript {
    ext.kotlin_version = '1.4.32'
    repositories {
        google()
        jcenter()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:4.0.1'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

In particular, this last edit (line 2) made my day.

Enjoy Flutter and OSM!

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This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.