MainActivity.scala

class MainActivity extends BaseActivity {

  private lazy val signalStr      : PhoneStateListener = onSignalChanged((signalStrength) ⇒ {
    if (signalStrength != null) {
      lazy val signalWrapper = new SignalArrayWrapper(signalStrength.toString)
      filteredSignals = signalWrapper.filterSignals(signalStrength.toString)
      displayDebugInfo(signalWrapper)
      displaySignalInfo(filteredSignals)
    }
  })

  private      var filteredSignals: Array[String]      = null
  private      var sigInfoIds     : TypedArray         = null
  private      var tm             : TelephonyManager   = null

  /**
    * Property for our telephony manager.
    * Some stupid phones kill this service on resume (chinese phones...looking at you...)
    * so in order to avoid that, we'll make sure it's never null
    *
    * @return
    */
  private def Tm: TelephonyManager = {
    tm = if (tm == null) this.service[TelephonyManager](Context.TELEPHONY_SERVICE) else tm
    tm
  }
}

object MainActivity {
  def onSignalChanged(callback: (SignalStrength) ⇒ Unit): PhoneStateListener = new PhoneStateListener {
    override def onSignalStrengthsChanged(signalStrength: SignalStrength) = callback(signalStrength)
  }
}