tableview:cellForRowAtIndexPath not getting called

Question

I have a tableview which loads peripherals received from BLE. ThisNSMutableArray is maintained in the appDelegate. Whenever a new peripheral is received in the app I add it to the array.

My problem is that everything works fine on first run and the table updates accordingly and I use the app for a while. Then I reset(CoreData, UserDefaults in app) my app and go back to the initial screen.

I use the following code to get back to initial screen of my app

class func showStartScreen() {
    let storyboard = UIStoryboard.init(name: "Main", bundle: nil)
    let nav = storyboard.instantiateInitialViewController()
    (UIApplication.sharedApplication().delegate)!.window!!.rootViewController = nav
    (UIApplication.sharedApplication().delegate)!.window!!.makeKeyAndVisible()
}

When I reset app data and come back to the screen where I display the peripherals in the tableview, it doesn't updat. I can see that the peripherals are added in the array but when I reload the tableview tableview:cellForRowAtIndexPath is not called. I tried to add a single dummy cell into the table and at that point tableview:cellForRowAtIndexPath is called properly but only for the dummy cell.

numberOfRowsInSection returns the correct value and my datasource and delegate are correctly set too. I clear the list every time a scan is started for BLE peripherals

In AppDelegate:

func discoveredPeripheral(peripheral: CAPeripheral) {
    print("added peripheral")
    var isDuplicate:Bool = false
    for object in scannedPeripherals!  {
        if object is CAPeripheral {
            let newPeripheral = object as! CAPeripheral
            // Need to add check of nil
            if newPeripheral.peripheral_UUID == peripheral.peripheral_UUID {
                isDuplicate = true
            }
        }
    }
    if (!isDuplicate) {
        self.scannedPeripherals?.addObject(peripheral)
    }
}

In ScanVC:

   func discoveredPeripheral(peripheral: CAPeripheral) {

    dispatch_async(dispatch_get_main_queue()) {
        self.peripheralTableView.reloadData()
    }
}

Hope I have explained well. Why is tableview:cellForRowAtIndexPath not called when I clearly have data to display?

Make sure did you set delegate and datasource of your tableView? — iPatel, Nov 24 '17 at 12:38
Are you reloading the table? Please post the appropriate snippets of code. — mikep, Nov 24 '17 at 12:40
@mikep have added code for adding peripherals and reloading data — Amogh Shettigar, Nov 24 '17 at 12:43
@iPatel yes I have checked for datasource and delegate. They are set correctly. — Amogh Shettigar, Nov 24 '17 at 12:44
Make sure you also see [cellForRowAtIndexPath: not called](https://stackoverflow.com/questions/7712325/cellforrowatindexpath-not-called) — mfaani, Nov 24 '17 at 17:43

Illya Bakurov · Answer 1 · 2017-11-24T17:24:48.247

0

If you say that you come back to initial viewController after cleaning CoreData and UserDefaults, I assume that it is why you don't see anything in your tableView, because you store found peripherals into CoreData and you clean it? Call discoveredPeripheral when you come to initial controller.

edited Nov 24 '17 at 17:24

answered Nov 24 '17 at 17:19

Illya Bakurov

486
5
11

I don't store peripherals in core data. I make a new search every time my ScanVC is loaded. I have mentioned that I receive the data but cellForRowAtIndexPath is not called when reloading the table view. – Amogh Shettigar Nov 25 '17 at 17:26

tableview:cellForRowAtIndexPath not getting called

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