Swift - How to update ProgressView using while loop?

Question

Created Jan ’21

Replies 1

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It's my first iOS app and I want to update ProgressView using while loop. I need help, It's not working says "UI element cannot be updated in background thread"

Code Block func update() {
        DispatchQueue.global().async {
            var current:Int = 0
            let total = 100
            while (current < total) {
                current += 1
                self.progress.setProgress(Float(current / total), animated: true)
                self.text.text = "Hello: " + String(current)
                print(Float(current / total))
                sleep(UInt32(0.1))
            }
        }
    }

Answered by Claude31 in 657559022

Update must occur in main thread

Code Block func update() {
        DispatchQueue.global().async {
            var current:Int = 0
            let total = 100
            while (current < total) {
                current += 1
                DispatchQueue.main.async {  // To update UI
                    self.progress.setProgress(Float(current / total), animated: true)
                	self.text.text = "Hello: " + String(current)
                	print(Float(current / total))
                }
                sleep(UInt32(0.1))
            }
        }
    }

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Answer 1

Claude31 OP

Jan ’21

Accepted Answer

Update must occur in main thread

Code Block func update() {
        DispatchQueue.global().async {
            var current:Int = 0
            let total = 100
            while (current < total) {
                current += 1
                DispatchQueue.main.async {  // To update UI
                    self.progress.setProgress(Float(current / total), animated: true)
                	self.text.text = "Hello: " + String(current)
                	print(Float(current / total))
                }
                sleep(UInt32(0.1))
            }
        }
    }

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