UILabel text is not updated even in MainThread

Question

UILabel.text is not updated inside the main thread. labelOne is updated but labelTwo which is to show translated word is not updated. When I print translatedWord it prints right string to console but UILabel is not updated.

datatask = session.dataTask(with: request, completionHandler: {data, response, error in
    if error == nil {
        let receivedData = try? JSONSerialization.jsonObject(with: data!, options: []) as? [String: Any]

        DispatchQueue.main.async {
            self.labelOne.text = wordTobeTranslated

            let data = "\(String(describing: receivedData!["text"]))"
            let all =   data.components(separatedBy: "(")
            let afterAll = all[2]
            let last = afterAll.components(separatedBy:")" )

            self.translatedWord = last[0]

            self.importantWords.append(last[0])
            self.labelTwo.text = self.translatedWord
            print(self.translatedWord)
        }
    }
})
datatask?.resume()

tried to print `translatedWord` and verfied it's not empty – Shehata Gamal May 05 '19 at 10:22 — Shehata Gamal, May 05 '19 at 10:22
it prints right as I mentioned above – Selçuk Yıldız May 05 '19 at 10:25 — Selçuk Yıldız, May 05 '19 at 10:25
did you manage to find solution ? – Amogam Aug 04 '22 at 15:56 — Amogam, Aug 04 '22 at 15:56

Anand · Answer 1 · 2019-05-05T11:25:18.327

0

Some tips to debug your issue:

Try to set some hard coded string to labelTwo and check whether it is displaying. (or)
Update any value for labelTwo in Storyboard and check whether is is displaying.

If string is displayed from any of the above steps, then labelTwo is configured correctly in storyboard.

You can also try self.labelTwo.layoutIfNeeded() method after updating the text to force update the UI.

If none of the steps helps you, check the Font color of UILabel. If it is same as background color, it would not be seen.

edited May 05 '19 at 11:25

answered May 05 '19 at 10:32

Anand

1,820
2
18
25

hardcoded string works. it is not initiated in StoryBoard by AutoLayout. it is initiated in subviewsdidlayout() and I change the position of the parentView of that labels before getting translated word. – Selçuk Yıldız May 05 '19 at 10:40
and I changed that UILabel to UITextView. String is shown but I have to scroll to bottom to see that – Selçuk Yıldız May 05 '19 at 10:41
Can you still retain UILabel and try layoutIfNeeded() in it? – Anand May 05 '19 at 10:43
tried it but did not work. I also print as print(labelTwo.text!) it prints the string I wanted but it is not shown. isn't it weird – Selçuk Yıldız May 05 '19 at 10:48
Please check the font color of UILabel. If it is same as background color, then it would not be seen. – Anand May 05 '19 at 11:05
The string had linebreaks so it didnt show up in label. it is solved by removing line breaks – Selçuk Yıldız May 05 '19 at 12:57

score 0 · Answer 2 · answered May 06 '19 at 20:12

Looking at your code sample, it would appear that you’re trying to retrieve:

describing: receivedData!["text"]

from:

\(String(describing: receivedData!["text"]))

The problem is that the \(...) in a String literal results in string interpolation where the expression inside \( and ) will be evaluated and that’s what will be place in the string. And the String(describing: ...) will interpret the value and return a string representation. So, let’s say that receivedData!["text"] contained the word “Foo”. Then

let data = "\(String(describing: receivedData!["text"]))"

Would result in data containing the string, Optional("Foo").

If you want to remove that Optional(...) part, you should either unwrap the optional or use a nil-coalescing operator, ??. And frankly, rather than using string interpolation at all, I’d just do:

let data = String(describing: receivedData?["text"] ?? "")

score 0 · Answer 3 · answered Nov 20 '20 at 13:22

0

I know this is an old question, but for new searchers: Try setting number of lines of UILabel to Zero. It might be a constraints issue.

answered Nov 20 '20 at 13:22

mahdi

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UILabel text is not updated even in MainThread

3 Answers3