CODEWITHSUNDEEP
iosswiftuilabel
BHuelse
BHuelse

Reputation: 2981

Changing UILabel text has delay, but why?

in my app I want to set the text of an UILabel. The text comes from a JSON-object. I add my UILabel to my storyboard, set the IBOutlet and call my async-method to get my JSON-object. In the response-method I set the text of the UILabel. But the text change needs some seconds. When the response comes I print it to the console. There I can see, that the delay doesnt comes from the async-method. The response comes, I can see it in the console. Wait some seconds than the UIlabel changes. I dont understand this behaviour, is there a trick to refresh the UIlabel instantly?

some code:

@IBOutlet weak var label_news: UILabel!;

override func viewDidLoad() {
    super.viewDidLoad()
    self.label_news.text = "CHANGE";
    rcall.GetNews_GET_NewsResponse_0(self.NewsResponseHandler);
}

func NewsResponseHandler(resp:NewsResponse!){
    self.label_news.text = resp.NewsText;
    println(resp.NewsText);
}

Sorry if this is a beginner question, swift and storyboards are totally new for me.

best regards

Upvotes: 2

Views: 2389

Answers (2)

kometen
kometen

Reputation: 7802

c_rath's answer is correct. In swift 3 the syntax was changed (yet again) to

DispatchQueue.main.async {
    self. label_news?.text = resp.NewsText
}

Upvotes: 0

c_rath
c_rath

Reputation: 3628

Like what Rob stated in the comment, all UI changes need to be done on the main thread. I haven't implemented it in Swift yet, but the Objective-C and what I'm assuming would be the Swift is below...

Objective-C

dispatch_async(dispatch_get_main_queue(), ^{
    self.label_news.text = resp.NewsText;
});

Swift:

dispatch_async(dispatch_get_main_queue()) {
    self.label_news.text = resp.NewsText;
}

Upvotes: 9

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