startDate, endDate, and adding text to label in ViewController - ios

Question

So I am having a few bugs and errors in my ViewController code in my app. First, in my line:
let predicate = HKQuery.predicateForSamplesWithStartDate(startDate,endDate: endDate ,options: .None)
I get the following error: use of unresolved identifier 'endDate'
This is weird. Is it because I have not made them into NSDate objects? How would I go about doing that?
As for my second question, it is not exactly a bug, I simply do not know how to do something. I have connected my label from the storyboard into my view controller. I want to get the data I collect to simply print onto the screen in the label. I know how to do this in most situations but I am lost as to how I can do this within my current configuration. I don't want the user to press a button or anything, I just want it to automatically display by default...Any help is greatly appreciated!!!
I have included all my code below:
import UIKit
import HealthKit
class ViewController: UIViewController {
#IBOutlet weak var displayData: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
// create store
let healthStore = HKHealthStore()
// create an object type to request an authorization for a specific category, here is SleepAnalysis
if let sleepType = HKObjectType.categoryTypeForIdentifier(HKCategoryTypeIdentifierSleepAnalysis) {
let setType = Set<HKSampleType>(arrayLiteral: sleepType)
healthStore.requestAuthorizationToShareTypes(setType, readTypes: setType, completion: { (success, error) -> Void in
// here is your code
})
}
if let sleepType = HKObjectType.categoryTypeForIdentifier(HKCategoryTypeIdentifierSleepAnalysis) {
// we create a predicate to filter our data
let predicate = HKQuery.predicateForSamplesWithStartDate(startDate,endDate: endDate ,options: .None)
// I had a sortDescriptor to get the recent data first
let sortDescriptor = NSSortDescriptor(key: HKSampleSortIdentifierEndDate, ascending: false)
// we create our query with a block completion to execute
let query = HKSampleQuery(sampleType: sleepType, predicate: predicate, limit: 30, sortDescriptors: [sortDescriptor]) { (query, tmpResult, error) -> Void in

Answer 1

endDate is undefined - you have not actually created a variable that represents endDate - thus the compiler is telling you that. And, also, startDate is also undefined, even though the compiler hasn't told you that yet. In the least, you need to create NSDates.
let startDate = NSDate()
let endDate = NSDate()
More specifically, you'll need to create them in the range for which you want to query.
Regarding showing the data by default, simply set the UILabel's text in viewDidLoad. I'm assuming that you want to set this text in response to the HealthKit query? If so, you can still do that in viewDidLoad
So, to use your query, it needs to be provided to executeQuery on healthStore Here's some code that you could use with what you posted:
healthStore.executeQuery(HKSampleQuery(
sampleType: sleepType,
predicate: predicate,
limit: 30,
sortDescriptors: [sortDescriptor],
resultsHandler: { (query: HKSampleQuery!, results: [AnyObject]!, err: NSError?) -> Void in
if err != nil {
// ERROR Occurred, handled it
println(err)
return
}
var labelText = ""
for result in results as [HKQuantitySample]! {
// SUCCESS, use results here
labelText += result
}
displayData.text = labelText
}
))