A skeleton for a gradle file to augment ExtJS's Sencha Cmd-generated build scripts. This particular one assumes the application is in a workspace.

build.gradle

ant.importBuild 'build.xml'

def packages_dir = file('../packages')

clean {
  doLast { delete 'bootstrap.js', 'bootstrap.css', 'bootstrap.json' }
}

refresh {
  inputs.dir 'app'
  inputs.file 'app.json'
  packages_dir.listFiles().each() { package_dir -> inputs.dir new File(package_dir, 'src') }

  outputs.file file('bootstrap.js')
  outputs.file file('bootstrap.json')
}

js {
  inputs.dir 'app'
  packages_dir.listFiles().each() { package_dir -> inputs.dir new File(package_dir, 'src') }
  outputs.file file("../build/${this.property('build.environment')}/${projectName}/app.js")
}

resources {
  inputs.dir 'resources'
  packages_dir.listFiles().each() { package_dir -> inputs.dir new File(package_dir, 'resources') }
  outputs.file file("../build/${this.property('build.environment')}/${projectName}/resources")
}

sass {
  inputs.dir 'sass'
  packages_dir.listFiles().each() { package_dir -> inputs.dir new File(package_dir, 'sass') }
  outputs.file file("../build/${this.property('build.environment')}/${projectName}/resources/${projectName}-all.css")
  outputs.file file('bootstrap.css')
}

page {
  // what are the inputs to page, I wonder?
  // the outputs are the microloader.js and the index.html...
}

gradle.properties

# the default Build Environment. Production is the default for Sencha Cmd. 
# Use -Dbuild.environment on the command line to change, otherwise it doesn't get passed to the ant build properly
build.environment=production

# The project name. Should match what is in the app.json file
projectName=MyApp