`Running 'gradle assembleDebug'` forever...

Steps to Reproduce

1. Create a new Flutter project
2. Start the Android emulator.
3. Click the ‘Run’ button.

The console says Launching lib\main.dart on Android SDK built for x86 64 in debug mode...

The background tasks thing says Running 'gradle assembleDebug'..., and then it just spins forever, never getting anywhere. There doesn’t seem to be any way to see the gradle output either so I have no idea why it isn’t working.

After about 5-10 mins exactly 5 mins (you should definitely reduce that timeout to something saner) the console says:

Observatory connection never became ready.
Application finished.

Version info

[√] Flutter (on Microsoft Windows [Version 10.0.15063], channel alpha)
    • Flutter at C:\Users\Tim\Flutter\flutter
    • Framework revision dc4ca8db83 (3 days ago), 2017-05-11 15:33:29 -0700
    • Engine revision f99d3ef108
    • Tools Dart version 1.23.0-dev.11.11

[√] Android toolchain - develop for Android devices (Android SDK 25.0.3)
    • Android SDK at C:\Users\Tim\AppData\Local\Android\sdk
    • Platform android-25, build-tools 25.0.3
    • Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java
    • Java version: OpenJDK Runtime Environment (build 1.8.0_112-release-b06)

[√] Android Studio (version 2.3)
    • Android Studio at C:\Program Files\Android\Android Studio
    • Gradle version 3.2
    • Java version: OpenJDK Runtime Environment (build 1.8.0_112-release-b06)

[√] IntelliJ IDEA Community Edition (version 2017.1)
    • Dart plugin version 171.4424
    • Flutter plugin version 13.1

[√] Connected devices
    • Android SDK built for x86 64 • emulator-5554 • android-x64 • Android 7.1.1 (API 25) (emulator)

[tvolkert]

https://github.com/flutter/flutter/pull/10092 may fix this

[WesleyBatista]

After a bit of research I was suspecting that the slow internet link was the cause, and I kind of verified this by checking the network activity of my computer after running the flutter run -v and it was consuming all bandwidth (max download speed here was 224KB/s).

I was a bit more patient and I started getting this error:

[+534089 ms] FAILURE: Build failed with an exception.
[   +1 ms] * What went wrong:
[        ] A problem occurred configuring root project 'android'.
[        ] > Could not resolve all artifacts for configuration ':classpath'.
[        ]    > Could not download kotlin-compiler-embeddable.jar (org.jetbrains.kotlin:kotlin-compiler-embeddable:1.3.50)
[        ]       > Could not get resource 'https://jcenter.bintray.com/org/jetbrains/kotlin/kotlin-compiler-embeddable/1.3.50/kotlin-compiler-embeddable-1.3.50.jar'.
[        ]          > Read timed out

It tries to download resources configuring the project, so it might happen just for the first time.

A bit sad but that’s it, hope this help someone else. cheers!