title: Reverse Java bindings with gomobile and fyne.io
body: <p>I have a fairly simple application that in theory should use Android Java API to get the location ( inspired by <a href="https://stackoverflow.com/a/45133431/741404">this</a> answer ):</p>
  <pre><code>package main
  
  import (
      &quot;Java/android/content/Context&quot;
      &quot;Java/android/location/LocationManager&quot;
      &quot;fyne.io/fyne/app&quot;
      &quot;fyne.io/fyne/widget&quot;
  )
  
  func GetLocation() string {
      locationManager := ctx.GetSystemService(Context.LOCATION_SERVICE)
      location := locationManager.GetLastKnownLocation(LocationManager.GPS_PROVIDER)
      lat := location.GetLatitude()
      lng := location.GetLongitude()
      return fmt.Sprintf(&quot;%f:%f&quot;, lat, lng)
  }
  
  func main() {
      a := app.New()
      w := a.NewWindow(&quot;Location&quot;)
  
      loc := widget.NewLabel(&quot;Location defined &quot; + GetLocation())
      w.SetContent(widget.NewVBox(
          loc,
      ))
  
      w.ShowAndRun()
  }
  
  </code></pre>
  <p>Yet I can't get it working with the build command as <code>fyne package -os android -appID com.user.fynedemo -icon icon.png</code> - it fails with the error:</p>
  <pre><code>fyne package -os android -appID com.jdevelop.fynedemo -icon 1x1-00000000.png
  go build -buildmode=c-shared -o /tmp/gomobile-work-028676736/lib/armeabi-v7a/libfynedemo.so fynedemo failed: exit status 1
  a.go:3:8: package Java/android/content/Context is not in GOROOT (/usr/lib/go/src/Java/android/content/Context)
  a.go:4:8: package Java/android/location/LocationManager is not in GOROOT (/usr/lib/go/src/Java/android/location/LocationManager)
  </code></pre>
  <p>To me it looks like Go-&gt;Java bindings are not generated, so I wonder what would be the first step for getting this working?</p>