Ufdjrw

I want to add a Progress bar to a tableViewController.

I have one function called HelpersFunctions which do all the calculation.
The function doCalculation is responsible for the calculation.

So, I add the following notification to doCalculation as follow:

NotificationCenter.default.post(name: .return_progress, object: self)
for i in 1...n1 
 //Do all the calculation

So, once I reach NotificationCenter.default.post, it will move to a Tableview Controller called CreateNewElementVC

now, inside the ViewDidLoad, I added the following line:

//progress
NotificationCenter.default.addObserver(self, selector: #selector(showProgress), name: .return_progress, object: nil)

In the same swift file, I added the following:

let container_elementProperty: ProgressBarView = 
 let view = ProgressBarView()
 view.backgroundColor = UIColor(white: 0, alpha: 0.5)
 view.translatesAutoresizingMaskIntoConstraints = false
 return view
()

 @objc func showProgress() 
 if(progressCounter > 1.0)timer.invalidate()
 print("Step 1")
 container_elementProperty.frame = CGRect(x: 100, y: 100, width: 200, height: 200)
 container_elementProperty.backgroundColor = UIColor(white: 0, alpha: 0.5)
 container_elementProperty.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleDismiss)))

 let queue = DispatchQueue(label: "queue1", qos: .userInteractive)
 queue.async 
 print("Step 2")
 self.view.addSubview(self.container_elementProperty)

 

 //view.addSubview(container_elementProperty)
 print("Step 3")
 container_elementProperty.progress = progressCounter
 progressCounter = progressCounter + progressIncrement

 let x1: Float = Float(start_Counting)
 let x2: Float = Float(End_Counting)

 let xx: Float = x1 / x2 * 100

 print("Start at: (xx) %)")

So, first I put all the required data in the CreateNewElementVC, then there is a button called run to do all the calculation and then it will move to another TableViewController with all the result.

So while I am inside the function doCalculation, the progress bar should appear .

In fact, the Progress bar container_elementProperty (UIview) appeared just after the calculation is completed which make the progress bar is useless.

Any idea how to make the View called container_elementProperty UIView to be seen ?

I am close to solve this issue as I can see the progress in the stack as below image, I just want to show this on the screen before completing the calculation.

Why I am not able to put the view on the screen while doing the calculation as you can see that step 2 ran first.
The warning related to this issue is: UIView.addSubview(_:) must be used from main thread only.

A Sample Project can be checked on this link at github.
Appreciate any kind of support.

• To simulate a progress, such as a network request you cannot simply do a for loop in the main thread, you should use GCD.


• To update the progress of an ongoing action use Delegation, not KVO.


• Using global variables makes your code flawed, avoid it!

This is a working version of your code.