How to modify an existing BLECentral class into a singleton class? - ios

Question

Hi I'm trying to make the BLE Central class into a Singleton class?
I'm running into a few crashes while trying to implement it.
Here is my code:
//This is the BLE Central Class
import Foundation
import UIKit
import CoreBluetooth
var txCharacteristic : CBCharacteristic?
var rxCharacteristic : CBCharacteristic?
var blePeripheral : CBPeripheral?
var characteristicASCIIValue = NSString()
class BLECentralViewController : UIViewController, CBCentralManagerDelegate, CBPeripheralDelegate, UITableViewDelegate, UITableViewDataSource{
//Data
var centralManager : CBCentralManager!
var RSSIs = [NSNumber]()
var data = NSMutableData()
var writeData: String = ""
var peripherals: [CBPeripheral] = []
var characteristicValue = [CBUUID: NSData]()
var timer = Timer()
var characteristics = [String : CBCharacteristic]()
//UI
#IBOutlet weak var baseTableView: UITableView!
#IBOutlet weak var refreshButton: UIBarButtonItem!
#IBAction func refreshAction(_ sender: AnyObject) {
disconnectFromDevice()
self.peripherals = []
self.RSSIs = []
self.baseTableView.reloadData()
startScan()
}
override func viewDidLoad() {
super.viewDidLoad()
self.baseTableView.delegate = self
self.baseTableView.dataSource = self
self.baseTableView.reloadData()
centralManager = CBCentralManager(delegate: self, queue: nil)
let backButton = UIBarButtonItem(title: "Disconnect", style: .plain, target: nil, action: nil)
navigationItem.backBarButtonItem = backButton
}
override func viewDidAppear(_ animated: Bool) {
disconnectFromDevice()
super.viewDidAppear(animated)
refreshScanView()
print("View Cleared")
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
print("Stop Scanning")
centralManager?.stopScan()
}
/*Okay, now that we have our CBCentalManager up and running, it's time to start searching for devices. You can do this by calling the "scanForPeripherals" method.*/
func startScan() {
peripherals = []
print("Now Scanning...")
self.timer.invalidate()
centralManager?.scanForPeripherals(withServices: [BLEService_UUID] , options: [CBCentralManagerScanOptionAllowDuplicatesKey:false])
Timer.scheduledTimer(timeInterval: 17, target: self, selector: #selector(self.cancelScan), userInfo: nil, repeats: false)
}
/*We also need to stop scanning at some point so we'll also create a function that calls "stopScan"*/
func cancelScan() {
self.centralManager?.stopScan()
print("Scan Stopped")
print("Number of Peripherals Found: \(peripherals.count)")
}
func refreshScanView() {
baseTableView.reloadData()
}
//-Terminate all Peripheral Connection
/*
Call this when things either go wrong, or you're done with the connection.
This cancels any subscriptions if there are any, or straight disconnects if not.
(didUpdateNotificationStateForCharacteristic will cancel the connection if a subscription is involved)
*/
func disconnectFromDevice () {
if blePeripheral != nil {
// We have a connection to the device but we are not subscribed to the Transfer Characteristic for some reason.
// Therefore, we will just disconnect from the peripheral
centralManager?.cancelPeripheralConnection(blePeripheral!)
}
}
func restoreCentralManager() {
//Restores Central Manager delegate if something went wrong
centralManager?.delegate = self
}
func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral,advertisementData: [String : Any], rssi RSSI: NSNumber) {
blePeripheral = peripheral
self.peripherals.append(peripheral)
self.RSSIs.append(RSSI)
peripheral.delegate = self
self.baseTableView.reloadData()
if blePeripheral == nil {
print("Found new pheripheral devices with services")
print("Peripheral name: \(String(describing: peripheral.name))")
print("**********************************")
print ("Advertisement Data : \(advertisementData)")
}
}
//Peripheral Connections: Connecting, Connected, Disconnected
//-Connection
func connectToDevice () {
centralManager?.connect(blePeripheral!, options: nil)
}
//-Connected
func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral) {
print("*****************************")
print("Connection complete")
print("Peripheral info: \(String(describing: blePeripheral))")
//Stop Scan- We don't need to scan once we've connected to a peripheral. We got what we came for.
centralManager?.stopScan()
print("Scan Stopped")
//Erase data that we might have
data.length = 0
//Discovery callback
peripheral.delegate = self
//Only look for services that matches transmit uuid
peripheral.discoverServices([BLEService_UUID])
//Once connected, move to new view controller to manager incoming and outgoing data
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let firstVC = storyboard.instantiateViewController(withIdentifier: "FirstViewController") as! FirstViewController
firstVC.peripheral = peripheral
navigationController?.pushViewController(firstVC, animated: true)
}
func centralManager(_ central: CBCentralManager, didFailToConnect peripheral: CBPeripheral, error: Error?) {
if error != nil {
print("Failed to connect to peripheral")
return
}
}
func disconnectAllConnection() {
centralManager.cancelPeripheralConnection(blePeripheral!)
}
func peripheral(_ peripheral: CBPeripheral, didDiscoverServices error: Error?) {
print("*******************************************************")
if ((error) != nil) {
print("Error discovering services: \(error!.localizedDescription)")
return
}
guard let services = peripheral.services else {
return
}
//We need to discover the all characteristic
for service in services {
peripheral.discoverCharacteristics(nil, for: service)
// bleService = service
}
print("Discovered Services: \(services)")
}
func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) {
print("*******************************************************")
if ((error) != nil) {
print("Error discovering services: \(error!.localizedDescription)")
return
}
guard let characteristics = service.characteristics else {
return
}
print("Found \(characteristics.count) characteristics!")
for characteristic in characteristics {
//looks for the right characteristic
if characteristic.uuid.isEqual(BLE_Characteristic_uuid_Rx) {
rxCharacteristic = characteristic
//Once found, subscribe to the this particular characteristic...
peripheral.setNotifyValue(true, for: rxCharacteristic!)
// We can return after calling CBPeripheral.setNotifyValue because CBPeripheralDelegate's
// didUpdateNotificationStateForCharacteristic method will be called automatically
peripheral.readValue(for: characteristic)
print("Rx Characteristic: \(characteristic.uuid)")
}
if characteristic.uuid.isEqual(BLE_Characteristic_uuid_Tx){
txCharacteristic = characteristic
print("Tx Characteristic: \(characteristic.uuid)")
}
peripheral.discoverDescriptors(for: characteristic)
}
}
func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic, error: Error?) {
if characteristic == rxCharacteristic {
if let ASCIIstring = NSString(data: characteristic.value!, encoding: String.Encoding.utf8.rawValue) {
characteristicASCIIValue = ASCIIstring
print("Value Recieved: \((characteristicASCIIValue as String))")
NotificationCenter.default.post(name:NSNotification.Name(rawValue: "Notify"), object: nil)
}
}
}
func peripheral(_ peripheral: CBPeripheral, didDiscoverDescriptorsFor characteristic: CBCharacteristic, error: Error?) {
print("*******************************************************")
if error != nil {
print("\(error.debugDescription)")
return
}
if ((characteristic.descriptors) != nil) {
for x in characteristic.descriptors!{
let descript = x as CBDescriptor!
print("function name: DidDiscoverDescriptorForChar \(String(describing: descript?.description))")
print("Rx Value \(String(describing: rxCharacteristic?.value))")
print("Tx Value \(String(describing: txCharacteristic?.value))")
}
}
}
func peripheral(_ peripheral: CBPeripheral, didUpdateNotificationStateFor characteristic: CBCharacteristic, error: Error?) {
print("*******************************************************")
if (error != nil) {
print("Error changing notification state:\(String(describing: error?.localizedDescription))")
} else {
print("Characteristic's value subscribed")
}
if (characteristic.isNotifying) {
print ("Subscribed. Notification has begun for: \(characteristic.uuid)")
}
}
func centralManager(_ central: CBCentralManager, didDisconnectPeripheral peripheral: CBPeripheral, error: Error?) {
print("Disconnected")
}
func peripheral(_ peripheral: CBPeripheral, didWriteValueFor characteristic: CBCharacteristic, error: Error?) {
guard error == nil else {
print("Error discovering services: error")
return
}
print("Message sent")
}
func peripheral(_ peripheral: CBPeripheral, didWriteValueFor descriptor: CBDescriptor, error: Error?) {
guard error == nil else {
print("Error discovering services: error")
return
}
print("Succeeded!")
}
//Table View Functions
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return self.peripherals.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "BlueCell") as! PeripheralTableViewCell
let peripheral = self.peripherals[indexPath.row]
let RSSI = self.RSSIs[indexPath.row]
if peripheral.name == nil {
cell.peripheralLabel.text = "nil"
} else {
cell.peripheralLabel.text = peripheral.name
}
cell.rssiLabel.text = "RSSI: \(RSSI)"
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
blePeripheral = peripherals[indexPath.row]
connectToDevice()
}
func centralManagerDidUpdateState(_ central: CBCentralManager) {
if central.state == CBManagerState.poweredOn {
// We will just handle it the easy way here: if Bluetooth is on, proceed...start scan!
print("Bluetooth Enabled")
startScan()
} else {
//If Bluetooth is off, display a UI alert message saying "Bluetooth is not enable" and "Make sure that your bluetooth is turned on"
print("Bluetooth Disabled- Make sure your Bluetooth is turned on")
let alertVC = UIAlertController(title: "Bluetooth is not enabled", message: "Make sure that your bluetooth is turned on", preferredStyle: UIAlertControllerStyle.alert)
let action = UIAlertAction(title: "ok", style: UIAlertActionStyle.default, handler: { (action: UIAlertAction) -> Void in
self.dismiss(animated: true, completion: nil)
})
alertVC.addAction(action)
self.present(alertVC, animated: true, completion: nil)
}
}
}
My questions are:
How can I modify the BLECentral class to use as a singleton so I
can call from any view controller class to read and write data?
Can I simply make the first view controller as a singleton instead of the BLE central and read/write by calling this from other view controller class?
Or can I extend the first view controller class scope by using
extension?
I'm currently able to read/write data but peripheral doesn't seem to
be called properly sometimes, therefore gets disconnected? Any
suggestions/fixes?
Here is my FirstViewController class:
class FirstViewController: UIViewController, UIPeripheralManagerDelegate {
var peripheralManager: CBPeripheralManager?
var peripheral: CBPeripheral!
viewDidLoad(){
//I'm calling the blePeripheral from BLE class to the peripheral in the current class
peripheral = blePeripheral
}
//I have a button here to send some data and only when I receive the data I want to go to the next view controller
#IBAction func login(_sender: AnyObject) {
//This is my write code
let bytes : [UInt8] = [ 0x1A, 0x2B, 0x3C, 0x4D ]
let Transmitdata = NSData(bytes: bytes, length: bytes.count)
peripheral.writeValue(Transmitdata as Data, for: txCharacteristic!, type: CBCharacteristicWriteType.withoutResponse)
print("Data Sent",Transmitdata)
//Give time for data to be received fromdevice
sleep(1)
//let ReceiveData = rxCharacteristic?.value
if let ReceiveData = ReceiveData {
let ReceivedNoOfBytes = ReceiveData.count
var ReceivedByteArray = [UInt8](repeating: 0, count: ReceivedNoOfBytes)
(ReceiveData as NSData).getBytes(&ReceivedByteArray, length: ReceivedNoOfBytes)
print("Data Received ",ReceivedByteArray)
//checking if we received the right data?
if(ReceivedByteArray[0] == 10 && ReceivedByteArray[1] == 20 && ReceivedByteArray[2] == 30 && ReceivedByteArray[3] == 40){
performSegue(withIdentifier: "Second_View", sender: self)
}
}
}
And the SecondViewController class:
class SecondViewController: UIViewController{
var firstview: FirstViewController?
var peripheralManager: CBPeripheralManager?
var peripheral: CBPeripheral!
override func viewWillAppear(_animated: Bool){
let peripheral = firstview?.peripheral
let peripheralManager = firstview?.peripheralManager
}
//I have another button here to direct me to third view controller class
#IBAction func mainmenu(_sender: AnyObject){
//send some bytes
//receiver some bytes
//similar to the first view controller
If correct data is received
{
performSegue(withIdentifier: "Main_M", sender: self)
}
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?){
if segue.destination is Main_M
{
let gotoM = segue.destination as? Main_M
gotoM?.peripheral = firstview?.peripheral
}
}