Wierd Crash on iphone app - ios

Question

i have a strange reaction with my app.
My app is working fine in almost 10 different devices and also has passed the tests and it's online. But one friend that has iPhone 5s with iOS 9.1 has an issue. When he tries to enter to a table view, which i append items to it with an API call with alamofire and swiftyjson.. the app crashes. From crashlytics i get this strange error
Crashed: com.apple.main-thread
0 Events Near Me 0x1000a532c specialized listMapViewController.tableView(UITableView, cellForRowAtIndexPath : NSIndexPath) -> UITableViewCell (listMapViewController.swift:196)
1 Events Near Me 0x1000a3c94 #objc listMapViewController.tableView(UITableView, cellForRowAtIndexPath : NSIndexPath) -> UITableViewCell (listMapViewController.swift)
2 UIKit 0x18a37220c -[UITableView _createPreparedCellForGlobalRow:withIndexPath:willDisplay:] + 688
3 UIKit 0x18a372364 -[UITableView _createPreparedCellForGlobalRow:willDisplay:] + 80
4 UIKit 0x18a3617b8 -[UITableView _updateVisibleCellsNow:isRecursive:] + 2440
5 UIKit 0x18a376f0c -[UITableView _performWithCachedTraitCollection:] + 104
6 UIKit 0x18a10f22c -[UITableView layoutSubviews] + 176
7 UIKit 0x18a01f7ac -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 644
8 QuartzCore 0x18981eb58 -[CALayer layoutSublayers] + 148
9 QuartzCore 0x189819764 CA::Layer::layout_if_needed(CA::Transaction*) + 292
10 QuartzCore 0x189819624 CA::Layer::layout_and_display_if_needed(CA::Transaction*) + 32
11 QuartzCore 0x189818cc0 CA::Context::commit_transaction(CA::Transaction*) + 252
12 QuartzCore 0x189818a08 CA::Transaction::commit() + 512
13 QuartzCore 0x1898120f8 CA::Transaction::observer_callback(__CFRunLoopObserver*, unsigned long, void*) + 80
14 CoreFoundation 0x184a47bd0 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 32
15 CoreFoundation 0x184a45974 __CFRunLoopDoObservers + 372
16 CoreFoundation 0x184a45da4 __CFRunLoopRun + 928
17 CoreFoundation 0x184974ca0 CFRunLoopRunSpecific + 384
18 GraphicsServices 0x18fbb0088 GSEventRunModal + 180
19 UIKit 0x18a08cffc UIApplicationMain + 204
20 Events Near Me 0x100095eec main (AppDelegate.swift:15)
21 libdyld.dylib 0x199da28b8 start + 4
And in the line 196 this is the code
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as! locationEventsTableViewCell
var dict = arrRes[indexPath.row]
cell.eventTitle.text = dict["eventName"] as? String //here is the issue
So to explain you a bit, with this app you get some events near you depending on your location. I have a protection if there are no events there is a message. But we leave a couple of blocks away and i can get events, among with the cell.eventTitle... but my friend's iPhone crashes through it.
Any idea?
P.S. i'm now downloading iOS 9.1 to my simulator. Another friend with iPhone 5 doesnt have that issue.

Answer 1

As you say that other iphones doesn't have this problem I assumed that your friend's iphone maybe is overloaded from apps or anything else and it doesn't take the json variables in time!
So I suggest first to use if statements to avoid errors like this:
if dict["eventName"] as? String != nil {
cell.eventTitle.text = dict["eventName"] as? String
}
And if you want in your next update maybe you could use completions to reload your tableView data.
Hope it helps.