I'm building an app that sends (every x seconds) to an API the location values with some extra values (session, ID, etc) that is working nice (see here Update CLLocation Manager on another method). But for improved feature, we are considering the device can lost (for some amount of time) internet connection. So I need to temporary store all values and when reconnected send them again to the API.
I'm considering several ways to do it:
Core Data (difficult implementation)
Realm (very little experience)
NSDisctionary
Can anyone suggest (and show how, if possible) the best way to implement this feature?
If you want to store a some of non-sensitive values (such as a password), I suggest to use NSUserDefaults, you can easily use it like a dictionary:
Note: Swift 2 Code.
For example:
// shared instance (singleton)
let userDefaults = NSUserDefaults.standardUserDefaults()
// **storing**:
let myString = "my string"
userDefaults.setObject(myString, forKey: "kMyString")
let myInt = 101
userDefaults.setInteger(myInt, forKey: "kMyInt")
let myBool = true
userDefaults.setBool(myBool, forKey: "kMyBool")
userDefaults.synchronize()
// **retrieving**:
//use optional binding for objects to check if it's nil
if let myRetrievedString = userDefaults.objectForKey("kMyString") as? String {
print(myRetrievedString)
} else {
// if it's nil
print("there is now value for key: kMyString")
}
// if there is no value for key: kMyInt, the output should be zero by default
let myRetrievedInt = userDefaults.integerForKey("kMyInt")
// if there is no value for key: kMyBool, the output should be false by default
let myRetrievedBool = userDefaults.boolForKey("kMyBool")
Tadaaaaaa:
func arrayOfDictionaries() {
var offline:[[String:AnyObject]] = []
offline.append(["LATITUDE: ": userLocation.coordinate.latitude, "LONGITUDE: ": userLocation.coordinate.longitude, "SPEED: ": userLocation.speed])
NSUserDefaults().setObject(offline, forKey: "offLine")
if let offLinePositions = NSUserDefaults().arrayForKey("offLine") as? [[String:AnyObject]] {
//print(offLinePositions)
for item in offLinePositions {
print(item["LATITUDE: "]! as! NSNumber) // A, B
print(item["LONGITUDE: "]! as! NSNumber) // 19.99, 4.99
print(item["SPEED: "]! as! NSNumber) // 1, 2
}
}
}
Related
I want to save new objects via a view controller in my app. However, I want these new objects to load when the app is logged into. I am using firebase to save data into a database, but how can I save an object and have it return when the app is logged into again? I am new-ish to programming, sorry for any potential confusion.
Here is where the goal information is read when the app has been logged into.
for i in 0 ... clientList.count - 1 {
screenHandle = ref?.child(organizationCode).child(clientList[i].name).observe(.value, with: { (snapshot) in
let clientStuffLoad = snapshot.value as! [String:Any]
if clientStuffLoad["Goal 1 Description"] != nil {
clientList[i].goal1 = clientStuffLoad["Goal 1"] as! String
} else {
clientList[i].goal1 = ""
}
This is essentially what I have regarding adding a new member to the class Client:
#IBAction func addingClientSaveButton(_ sender: Any) {
var client7 = Client(name: addingClientName.text!,
goal1: addingClientGoal1.text!, goal2:
addingClientGoal2.text!,
goal3: addingClientGoal3.text!,
isSelected: false, s: 1,
ind: 1, targetBehavior1 : addingClientTB1.text!,
targetBehavior2 : addingClientTB2.text!,
targetBehavior3 : addingClientTB3.text!,
targetBehavior1Info : addingClientTB1Info.text!,
targetBehavior2Info : addingClientTB2Info.text!,
targetBehavior3Info : addingClientTB3Info.text!)
but I would like the object name to read the client name input as opposed to client7
The second part to this is that I want a way to write this to the database, and be able to read it at log in so that I can use the properties of the class and add to it when adding a new client.
This is a super broad question because it covers a lot of different aspects of working with Firebase; writing, reading, handling DataSnapshots etc. Also, I don't know what your data represents so I picked something for me to cover some of the aspects of working with Firebase.
There's no error checking but it works as is. I've commented along the way.
Firebase has no objects; just parent and child nodes. Everything can be thought of as key: value pairs like a dictionary. You cannot write an object or read an object. Only NSString, NSNumber, NSDictionary and the dreaded NSArray (or their Swift counterparts)
Let's start with a class - there's 100 ways to do this but I like classes to be responsible for their properties as well as accepting them and presenting them
class WineClass {
var wine_key = ""
var name = ""
var varietal = ""
//this is used when creating a new wine object before storing in firebase
init(withName: String, andVarietal: String) {
self.name = withName
self.varietal = andVarietal
}
//this is used when we are loading data from firebase to create the wineclass object
init(withSnapshot: DataSnapshot) {
let wineName = withSnapshot.childSnapshot(forPath: "wine_name").value as? String ?? "No Wine Name"
let wineDict = withSnapshot.value as! [String: Any]
let wineVarietal = wineDict["wine_varietal"] as? String ?? "No Wine Varietal"
self.wine_key = withSnapshot.key //when we read a wine, this will be it's reference in case we want to update or delete it
self.name = wineName
self.varietal = wineVarietal
}
//this is use to create a dictionary of key:value pairs to be written to firebase
func getWineDictForFirebase() -> [String: Any] {
let d = [
"wine_name": self.name,
"wine_varietal": self.varietal
]
return d
}
}
Then, we need a class var to store the WineClass's. This would be for example a dataSource for a tableView
var wineArray = [WineClass]() //a class var array to store my wines
Then I will give you two buttons, one that populates and writes some wine to Firebase and then a second that read them in and prints to console
func button0() {
self.writeWine(withName: "Scarecrow", andVarietal: "Red Blend")
self.writeWine(withName: "Ghost Horse", andVarietal: "Cabernet Sauvignon")
self.writeWine(withName: "Screaming Eagle", andVarietal: "Cabernet Sauvignon, Merlot, Cabernet Franc")
}
func button1() {
self.readWines()
}
And then the function that accepts some strings as properites for each wine and writes them to Firebase
func writeWine(withName: String, andVarietal: String) {
let newWine = WineClass(withName: withName, andVarietal: andVarietal) //create a new wine object
let wineListRef = self.ref.child("wine_list") //get a reference to my firebase wine_list
let thisWineRef = wineListRef.childByAutoId() //a new node for this wine
let d = newWine.getWineDictForFirebase() //get the wine properties as a dictionary
thisWineRef.setValue(d) //save it in firebase
}
and finally a function that reads in those wines, and prints their properties in console
func readWines() {
let wineRef = self.ref.child("wine_list")
wineRef.observeSingleEvent(of: .value, with: { snapshot in //we are reading in the entire wine node which will contain many child nodes
let allWines = snapshot.children.allObjects as! [DataSnapshot] //cast each child node as a DataSnapshot & store in array
for wineSnap in allWines { //iterate over each child node in the array
let wine = WineClass(withSnapshot: wineSnap) //create a new wine, ensuring we also keep track of it's key
self.wineArray.append(wine) //add to the array
}
for wine in self.wineArray {
print(wine.wine_key, wine.name, wine.varietal)
}
})
}
lastly, when button0 is clicked, our Firebase looks like this
wine_list
-LhbjhkEC8o9TUISCjdw
wine_name: "Scarecrow"
wine_varietal: "Red Blend"
-LhbjhkEC8o9TUISCjdx
wine_name: "Ghost Horse"
wine_varietal: "Cabernet Sauvignon"
-LhbjhkEC8o9TUISCjdy
wine_name: "Screaming Eagle"
wine_varietal: "Cabernet Sauvignon, Merlot, Cabernet Franc"
and then the output when button1 is clicked
-LhbjhkEC8o9TUISCjdw Scarecrow Red Blend
-LhbjhkEC8o9TUISCjdx Ghost Horse Cabernet Sauvignon
-LhbjhkEC8o9TUISCjdy Screaming Eagle Cabernet Sauvignon, Merlot, Cabernet Franc
Note that self.ref is a reference to the root node of my firebase yours will need to reference your firebase.
I need to retrieve price value of each product in the cart child, but how should I retrieve it and sum the retrieved value together?
Picture of my Firebase database structure
let uid = Auth.auth().currentUser?.uid
refProduct = Database.database().reference().child("users").child(uid!).child("cart")
refProduct.observeSingleEvent(of: .value) { (snapshot) in
for cartchild in snapshot.children{
let snap = cartchild as! DataSnapshot
let key = snap.value
.....
}
}
I would not store the price as a string, but as a number. You might want to add another field with currency if needed.
guard let uid = Auth.auth().currentUser?.uid else { return }
var sum: Double = 0
refProduct = Database.database().reference().child("users").child(uid).child("cart")
refProduct.observeSingleEvent(of: .value) { (snapshot) in
for cartchild in snapshot.children{
let snap = cartchild as! DataSnapshot
let data = snap.value as? [String: Any]
let price = data["ProductPrice"] as? Double ?? 0
sum += price
}
print("Final sum: \(sum)")
}
Not really tested, but this is the idea
Arvidurs is correct about storing the price as an int and the currency as a string, but the reason the answer isn't working for you is that it doesn't address that you're not correctly retrieving the data you want in the first place.
You have your cart folder, and it contains two product folders whose properties you're trying to retrieve. You can't retrieve and unwrap the values contained in those two folders by just referencing the parent cart folder. You need to individually access each folder within cart:
Database.database().reference().child("users").child(uid).child("cart").child("-Lf59bkQ5X3ivD6ue1SA")
Database.database().reference().child("users").child(uid).child("cart").child("-Lf5MiEGU357HWTMbxv8")
However, for this to work, you'll need access to each products autoID value, so you'll need to be storing each new product's childByAutoID value into an array or a dictionary so that you have them all available to access whatever data you need.
You'll need to implement this as you're storing the new product to the cart folder. I don't know exactly how you're currently saving each product, but you'll need to do something like this when you create your reference that you'll be saving to:
let newProductRef = Database.database().reference().child("users").child(uid).child("cart").childByAutoId()
let autoID = newProductRef.key
At that point, you'll be able to store autoID however you choose, and you'll have access to everything within the cart folder, and you can loop through all of your autoIDs and get whatever data you need. Example:
func getCartPriceSum(finished: #escaping ([String : Double]) -> Void){
let myGroup = DispatchGroup()
var sum = Double()
var currency = String()
for autoID in autoIdArray{
myGroup.enter()
let productRef = Database.database().reference().child("users").child(uid).child("cart").child(autoID)
productRef.observe(.value) { (snapshot) in
guard
let snapshotValue = snapshot.value as? NSDictionary,
let productPrice = snapshotValue["ProductPrice"] as? Double,
let priceCurrency = snapshotValue["PriceCurrency"] as? String//assuming you've adopted Arvidurs' method of storing the price data
else {
print("productPrice/priceCurreny nil")
return
}
sum += productPrice
currency = priceCurrency
}
myGroup.leave()
}
let priceSum = [currency : sum]
myGroup.notify(queue: .main) {
finished(priceSum)
}
}
And you could call the function like this:
getCartPriceSum { (priceSum) in
//do whatever you want with the priceSum
}
The only thing left for you to figure out is how you want to store those autoIDs.
This is how my Firebase looks like
Firebase ScreenShot
This is my code
override func viewDidLoad() {
var sum = 0
var counter = 0
super.viewDidLoad()
ref = Database.database().reference()
ref.child("WaterAdded").observe(.childAdded, with: { (snapshot) in
if let totalwateradded = snapshot.value as? [Int]{
while counter < (totalwateradded.count) {
var newValue = totalwateradded[counter]
sum += newValue
}
self.totalAdded.text = "\(sum)"
}
})
}
I want to grab all the number in Firebase and display the sum. But it display nothing.
You cannot directly cast snapshot.value to [Int], instead if you want to get all objects in your node you should use
let ref = Database.database().reference()
ref.child("WaterAdded").observe(.childAdded, with: { (snapshot) in
if let water = snapshot.value as? String{
guard let waterAmount = Int(water) else{return}
sum += waterAmount
}
})
that while loop is not needed as this will give you all the values in the database.
Edit
In the database you can use Strings and Ints to store numbers. You store them as Strings. If you load them in Swift you have to conditionally cast the value to String (as? String). The problem, however is that you can not do any arithmetic operations on strings so using the Int(water) statement you can convert it to Int. This operation can give an integer from a string if it contains a number, but it can also fail (e.g. Int("two")) and therefore we use guard let to make sure we only proceed to the next line if it can successfully convert to an Int. Afterwards we just add the int value to sum and done.
try...
if let snap = snapshot.value as? Dictionary [Sting: Any], let totalWaterAdded =
snap["\(yourDictionaryKey)"] as? Int{
//enter your code...
}
Here's the answer that reads the node, sums the values and print it to console.
let ref = self.ref.child("WaterAdded")
ref.observeSingleEvent(of: .value, with: { snapshot in
var x = 0
for child in snapshot.children {
let val = (child as! DataSnapshot).value as! Int
x = x + val
}
print("sum: \(x)")
})
We're using observeSingleEvent of .value in this case as there's really no reason for firebase to iterate over each child when we can do it a lot faster in code. Also, we don't need to be notified of childAdded events.
Tossing a guard statement in the mix may be a good idea but as long as you are sure the values will only be Int's, it's good to go as is.
Tested with the following structure
WaterAdded
a: 0
b: 1
c: 2
d: 3
and the output is
6
func checkPaid(utilityId : String) -> Int{
var amount:String = ""
var status = 0
print("inside new function ")
print ("\(utilityId) inside new function ")
self.databaseRefPayment.observe(DataEventType.value, with:{(DataSnapshot) in
if DataSnapshot.childrenCount > 0 {
for payments in DataSnapshot.children.allObjects as! [DataSnapshot]{
var paymentsObject = payments.value as? NSDictionary
/*
if(paymentsObject!["month"] as! String == monthCheck && paymentsObject!["year"] as! String == monthCheck && paymentsObject!["utilityid"] as! String == utilityId as! String){ */
if(paymentsObject!["utilityId"] as! String == utilityId){
amount = paymentsObject!["amount"] as! String
print(amount)
print("Ypur program is working perfect")
status = 1
}
}
}
})
return status
}
The above function is filtering the data present in payments node based on the value for utilityId getting passed in the function . But the strange thing is observe(DataEventType.value, with:{(DataSnapshot) this event is not getting triggered all the time . Its just skipping that portion unnecessarily . I am very new to firebase and getting really mad with these kind of unpredicted behaviours . Please help me in this . feel free to ask for any clarifications .
The firebase executes firebase query functions in different thread , so after u call check paid(), it runs the checkpaid() firebase query in another thread,and it will return from the function , eventhough ur query is running in the background..so it will seem like,checkpaid() is not working , but actually it's running on another thread.
I think you first fetch all the required data from payment, and store it in a list , and then use that list to compare with utility.
Every time this function is called it adds/resets the Key-Value Observer for whichever child node you are observing it doesn't actually check the value unless it is changed. I believe it is your intention to call checkPaid(utilityId:) to check the child is 'paid' by some means. There is no need to add a KVO if you are directly reading the value for a single snapshot. consider the following:
func checkPaid(utilityId: String) -> Bool {
//Assume it is not paid if we cannot verify it.
var isPaid = false
//Create a new reference to Firebase Database
var ref: DatabaseReference!
ref = Database.database().reference().child(utilityId)
//Get the values for the child, test if it is paid or not.
ref.queryOrderedByValue().observeSingleEvent(of: .value) { (snapshot) in
if (snapshot.value is NSNull) {
print("No Child With \(utilityId) Exists")
} else {
//child with utilityId exists, in case multiple utilityId's exist with the same value..
for child in snapshot.children.allObjects as! [DataSnapshot] {
if let values = child.value as? [String : AnyObject] {
let uid = child.key //utilityId
var month:String = ""
var year:String = ""
var amount:String = ""
//var amount:Double = 0.0
//get values from parent
if let m = values["month"] as? String {
month = m
}
if let y = values["year"] as? String {
year = y
}
if let a = values["amount"] as? String {
amount = a
}
/*
if let a = values["amount"] as? Double {
amount = a
}
*/
//??
if ((month == monthCheck) && (year == monthCheck)) {
isPaid = true
}
}
}
}
return isPaid
}
I am making one assumption here; that utilityId is the key for the child.
if you have parent nodes to utilityId you'll have to transverse those as well when you reference the database:
ref = Database.database().reference().child(utilities).child(utilityId) ..etc
If you need a KVO to update a local property I suggest adding/calling it in viewDidLoad, it's completion handler should take care of updating whichever properties are updated when they change in Firebase.
Ok, I am building an iMessage app and to transfer data back and forth I have to use URLQueryItems. I am working with an SKScene and need to transfer Ints, CGPoints, images, etc. Reading Apple's documentation and my own attempts it seems like you can only store strings in URLQueryItems.
As this us the only way to pass data back and forth, is there a (better) way to store other types of data? Currently I have been doing this:
func composeMessage(theScene: GameScene) {
let conversation = activeConversation
let session = conversation?.selectedMessage?.session ?? MSSession()
let layout = MSMessageTemplateLayout()
layout.caption = "Hello world!"
let message = MSMessage(session: session)
message.layout = layout
message.summaryText = "Sent Hello World message"
var components = URLComponents()
let queryItem = URLQueryItem(name: "score",value: theScene.score.description)
components.queryItems = [queryItem] //array of queryitems
message.url = components.url!
print("SENT:",message.url?.query)
conversation?.insert(message, completionHandler: nil)
}
Then on the flip side I have to convert this string back to an Int again. Doing this with CGPoints will be inefficient.. how would one pass something like a CGPoint in a URLQueryItem? Any other way than storing the x and y values as strings?
EDIT: This is how I have been receiving data from the other person and putting into their scene:
override func willBecomeActive(with conversation: MSConversation) {
// Called when the extension is about to move from the inactive to active state.
// This will happen when the extension is about to present UI.
// Use this method to configure the extension and restore previously stored state.
let val = conversation.selectedMessage?.url?.query?.description
print("GOT IT ", val)
if(val != nil)
{
scene.testTxt = val!
}
}
As you discovered, to pass data via URLQueryItem, you do have to convert everything to Strings since the information is supposed to be represented as a URL after all :) For CGPoint information, you can break the x and y values apart and send them as two separate Ints converted to String. Or, you can send it as a single String value in the form of "10,5" where 10 is the x and 5 is the y value but at the other end you would need to split the value on a comma first and then convert the resulting values back to Ints, something like this (at the other end):
let arr = cgPointValue.components(separatedBy:",")
let x = Int(arr[0])
let y = Int(arr[1])
For other types of data, you'd have to follow a similar tactic where you convert the values to String in some fashion. For images, if you have the image in your resources, you should be able to get away with passing just the name or an identifying number. For external images, a URL (or part of one if the images all come from the same server) should work. Otherwise, you might have to look at base64 encoding the image data or something if you use URLQueryItem but if you come to that point, you might want to look at what you are trying to achieve and if perhaps there is a better way to do it since large images could result in a lot of data being sent and I'm not sure if iMessage apps even support that. So you might want to look into limitations in the iMessage app data passing as well.
Hope this helps :)
You can use iMessageDataKit library for storing key-value pairs in your MSMessage objects. It makes setting and getting data really easy and straightforward like:
let message: MSMessage = MSMessage()
message.md.set(value: 7, forKey: "moveCount")
message.md.set(value: "john", forKey: "username")
message.md.set(values: [15.2, 70.1], forKey: "startPoint")
message.md.set(values: [20, 20], forKey: "boxSize")
if let moveCount = message.md.integer(forKey: "moveCount") {
print(moveCount)
}
if let username = message.md.string(forKey: "username") {
print(username)
}
if let startPoint = message.md.values(forKey: "startPoint") {
print("x: \(startPoint[0])")
print("y: \(startPoint[1])")
}
if let boxSize = message.md.values(forKey: "boxSize") {
let size = CGSize(width: CGFloat(boxSize[0] as? Float ?? 0),
height: CGFloat(boxSize[1] as? Float ?? 0))
print("box size: \(size)")
}
(Disclaimer: I'm the author of iMessageDataKit)