Building table view while getting number of rows from completion block - ios

Question

I am trying to retrieve the calendar events in swift 2, and I can not solve this: to build the table view I need to know the number of cells, which I can get from a method like this (for the sake of simplicity array is String):
func fetchCalendarEvents () -> [String] {
var arrayW = [String]()
let eventStore : EKEventStore = EKEventStore()
eventStore.requestAccessToEntityType(EKEntityType.Event, completion: {
granted, error in
if (granted) && (error == nil) {
print("access granted: \(granted)")
//do stuff...
}
else {
print("error: access not granted \(error)")
}
})
return arrayW
}
I am calling this method in viewDidLoad, and save the array to var eventArray. Immediately the following method gets called:
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return eventArray.count
}
The problem is that the completion block of the fetchCalendarEvents is not complete at this point, and therefore returns 0 (while there are events in the calendar).
My question: how can I handle building the table view from array that I get from method, that has completion block, and takes some time to be completed?

Answer 1

Add aBlockSelf.tableView.reloadData() in your calendar completion block to reload your table with fetched data.
Here aBlockSelf is a weak reference to self because its being passed to a block.
EDIT: Post OP comment - Try this:
weak var aBlockSelf = self

Answer 2

override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if (eventArray.count == 0) { //or unwrap value, depends on your code
return 0 // or 1, if you want add a 'Loading' cell
} else {
return eventArray.count
}
}
And, when you get eventArray, just reload table with
//without animation
tableView.reloadData()
//or with, but it can get little tricky
tableView.insertRowsAtIndexPaths(indexArray, withRowAnimation:UITableViewRowAnimationRight];

Answer 3

Make 2 cells type. One for events and one which just say "Loading...". While your block in progress show only 1 cell with "Loading...". When an events will retrieve hide this cell and reload table with events.
Cheers.

Answer 4

Ok, all seemed to answer relatively correct, but not exactly in the way that worked straight. What worked for me, is that instead of returning array, I just need to reload the table view after the for loop, where array is built up:
func fetchCalendarEvents () {
let eventStore : EKEventStore = EKEventStore()
eventStore.requestAccessToEntityType(EKEntityType.Event, completion: {
granted, error in
if (granted) && (error == nil) {
print("access granted: \(granted)")
let startDate=NSDate().dateByAddingTimeInterval(-60*60*24)
let endDate=NSDate().dateByAddingTimeInterval(60*60*24*3)
let predicate2 = eventStore.predicateForEventsWithStartDate(startDate, endDate: endDate, calendars: nil)
print("startDate:\(startDate) endDate:\(endDate)")
let events = eventStore.eventsMatchingPredicate(predicate2) as [EKEvent]!
if events != nil {
var arrayOfEvents = [CalendarEventObject]()
for event in events {
var eventObject: CalendarEventObject
// (ಠ_ಠ) HARDCODEDE
eventObject = CalendarEventObject(id: 0, title: event.title, location: event.location!, notes: event.notes!, startTime: event.startDate, endTime: event.endDate, host: "host", origin: "origin", numbers: ["0611111111", "0611111112"], passcodes: ["123456", "123457"], hostcodes: ["123458", "123459"], selectedNumber: "0611111113", selectedPasscode: "123457", selectedHostcode: "123459", scheduled: true, parsed: false, update: true, preferences: [], eventUrl: "www.youtube.com", attendees: [])
arrayOfEvents.append(eventObject)
}
self.eventArray = arrayOfEvents
//reload data after getting the array
dispatch_async(dispatch_get_main_queue(), { () -> Void in
self.tableView.reloadData()
})
}
}
else {
print("error: access not granted \(error)")
}
})
}