I want the user to be able to know how many times they have visited each class. Then add together the totals from each page together to form a group sum. I want to print the total sum in the log file in each of the two view controllers. So just one string should be printed.
class oneV: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
UserDefaults.standard.set(true, forKey: "VC1")
}
}
class twoV: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
UserDefaults.standard.set(true, forKey: "VC2")
}
}
If you mean visited each view controller, when you say visited each class. Then i'd recommend you do it viewDidAppear
.
class YourViewController: UIViewController {
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
let key = String(describing: type(of: self))
let count = UserDefaults.standard.value(forKey: key) as? Int ?? 0
UserDefaults.standard.set(value + 1, forKey: key)
}
}
To make it simpler, you could use an extension on UIViewController
.
extension UIViewController {
func updateVisitCount() {
let key = String(describing: type(of: self))
let count = UserDefaults.standard.value(forKey: key) as? Int ?? 0
UserDefaults.standard.set(count + 1, forKey: key)
}
}
Or, if you need this for every view controller that you create, then you can create a base view controller which you would use everywhere instead of UIViewController
.
class BaseViewController: UIViewController {
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
updateVisitCount()
}
}
The most automatic solution would be inject the accounting call in viewDidLoad
without replacing the original viewDidLoad
.
Here demo purpose i've created a sample Playground
import UIKit
import PlaygroundSupport
extension UIViewController {
@objc dynamic func substitutedViewDidAppear() {
print("This is injected code in view did appear")
substitutedViewDidAppear() // it may look like recursive, but it isn't, actually it calls the original `viewDidAppear` method.
}
class func swizzle() {
let originalMethod = class_getInstanceMethod(UIViewController.self, #selector(viewDidAppear(_:)))
let substitutedMethod = class_getInstanceMethod(UIViewController.self, #selector(substitutedViewDidAppear))
if let originalMethod = originalMethod,
let substitutedMethod = substitutedMethod {
print("swizzled")
method_exchangeImplementations(originalMethod, substitutedMethod)
} else {
print("not swizzled")
}
}
}
class MyViewController : UIViewController {
override func loadView() {
let view = UIView()
view.backgroundColor = .white
let label = UILabel()
label.frame = CGRect(x: 150, y: 200, width: 200, height: 20)
label.text = "Hello World!"
label.textColor = .black
view.addSubview(label)
self.view = view
print("view loaded")
}
}
// Swizzle
UIViewController.swizzle() // call this in @top of didFinishLaunchingWithOptions
// Present the view controller in the Live View window
PlaygroundPage.current.liveView = MyViewController()
Output:
swizzled
view loaded
This is injected code in view did appear
Now in the substitutedViewDidAppear
upper portion inject your counting code as @Rakesha Shastri Suggested, call the updateVisitCount
method inside of substitutedViewDidAppear
& place the UIViewController.swizzle()
in applicationDidFinishLaunchingWithOptions
before creating the root window.
Create a static variable. A static variable is a type of class, not object therefore throughout all objects a variable maybe maintained. I think this example may better explain how this works. Click here
In ViewDidLoad method call this function :
func updateVisitingCounter() {
var counter = UserDefaults.standard.integer(forKey: "firstPageCounter")
counter += 1
UserDefaults.standard.set(counter, forKey: "firstPageCounter")
}
You may set declare variables at project scope "outside of classes"
var vc1Count = 0
class oneV: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
vc1Count = vc1Count+1
}
}
var vc2Count = 0
class twoV: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
vc2Count = vc2Count+1
}
}
you can also declare these variables at a common place.
As per your requirements its kind of Analytics on app usage. You can implement in 2 ways
Sample code for storing Screen details in DB:
==> Create your Entity for Screen capture. ScreenVisit.
==> Store Data with screen name.
let entity = NSEntityDescription.entity(forEntityName: "ScreenVisit", in: context)
let newVisit = NSManagedObject(entity: entity!, insertInto: context)
newVisit.setValue("HomeScreen", forKey: "screenname")
newVisit.setValue("1", forKey: "visited")
do {
try context.save()
} catch {
print("Failed saving")
}
==> Fetch data where you required.
let request = NSFetchRequest<NSFetchRequestResult>(entityName: "ScreenVisit")
//request.predicate = NSPredicate(format: <Your Filter Logic>)
request.returnsObjectsAsFaults = false
do {
let result = try context.fetch(request)
for data in result as! [NSManagedObject] {
print(data.value(forKey: "screenname") as! String)
print(data.value(forKey: "visited") as! String)
}
} catch {
print("Failed")
}
Ref Links :
but as per my experience 2nd way is more convenient and powerful.
All depends on your requirements.
Hope this will helps you to get your user action captured.
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