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Scan and detect available networks in SUSI.AI Android app

We all have experienced Apple HomPad, Google Home, Alexa etc or read about smart speakers which offer interactive actions over voice commands. Smart speaker uses hotword for activation. They utilize WiFi, bluetooth and other wireless protocols.

SUSI.AI is also coming with an Open Source smart speaker using  as simple as a RaspberryPi for the speaker which can perform various actions like playing music etc over voice commands. To use SUSI Smart Speaker, you have to connect it to the SUSI iOS or Android App. You can manage your connected devices in SUSI Android,SUSI iOS and Web clients. Here we will see initial setups for connecting SUSI Smart Speaker with an Android device.

Unlike iOS, Android allows any app to change the WiFi settings of the phone if the specific permissions are added in the app and on the run time while using the app. To connect to a particular WiFi in android given that permissions are enabled a few lines of code is sufficient enough to connect to the new WiFi network, but in our case before connecting to the WiFi we must know that the SUSI.AI hotspot is available around or not.

To know if the SUSI hotspot is available or not we have to scan for the available WiFi networks present and then choose the SUSI WiFi hotspot.

The app simply detects the available WiFi networks and displays a set of them that have the name SUSI.AI. To detect the available WiFi networks we have used a BroadCastReceiver that listens for the action :

WifiManager.SCAN_RESULTS_AVAILABLE_ACTION

The broadcast receiver listens to this action and fetches the list of networks available. The broadcast receiver is registered after the objects of WifiReceiver class and WifiManager class are declared. Once the broadcast receiver is registered the object of WifiManager is used to start the scanning process of the available Wifi networks.

Here is the object of the WifiManager and WifiReceiver declared in the onCreate() method of the DeviceActivity.kt file :

mainWifi = application.getSystemService(Context.WIFI_SERVICE) as WifiManager
receiverWifi = WifiReceiver()

The broadcast receiver class that scans the available networks is as follows :

inner class WifiReceiver : BroadcastReceiver() {
   override fun onReceive(p0: Context?, p1: Intent?) {
       Timber.d(“Inside the app”)
       if (p1 != null) {
           if (p1.action.equals(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION)) {
               var wifiList: List<ScanResult> = ArrayList<ScanResult>()
               wifiList = mainWifi.getScanResults()
               devicePresenter.inflateList(wifiList)
           }

In the above code all the available networks on scanning are sent to the presenter for further processing.

In the presenter class in the method inflateList() the available WiFi networks list is scanned on the basis of their SSID and all the networks with name are “SUSI.AI” are selected and then displayed as a list to the user.

The inflateList() function is as follows :

override fun inflateList(list: List<ScanResult>) {
   Timber.d(“size “ + list.size)
   connections = ArrayList<String>()
   for (i in list.indices) {
       if (list[i].SSID.equals(utilModel.getString(R.string.device_name)))
           connections.add(list[i].SSID)
   }

   if (connections.size > 0) {
       deviceView?.setupAdapter(connections)
   } else {
       deviceView?.onDeviceConnectionError(utilModel.getString(R.string.no_device_found), utilModel.getString(R.string.setup_tut))
   }
}

Now after the wifi list is scanned the sorted and selected list is sent to the Recycler adapter that will display the list to available SUSI networks to the user.

CONCLUSION :

REFERENCES :

  1. Android Manipulation of wifi using WifiManager : https://medium.com/@josiassena/android-manipulating-wifi-using-the-wifimanager-9af77cb04c6a
  2. Scan and list all Wifi in Android : https://www.nplix.com/scan-list-wifi-network-android/
  3. Kotlin android broadcast receivers : https://www.techotopia.com/index.php/Kotlin_Android_Broadcast_Intents_and_Broadcast_Receivers

 

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