Swift-在后台加载ViewController

Question

i have a View Controller with a huge stack of Images in an Array. When i press the Button that takes me to View Controller it takes about 8-15 Seconds to load. Now I want to make a Loading screen so every time the app start, the View controller should be loaded in background.

How can I do this?

Thanks!

Answer 1

The best way to do that, relating to the final user experience, is using an Activity Indicator .

You should add it normally to your ViewController and relating it to your swift viewController'file.

When the loading will start, you must start to "spin" your activity indicator: in this way the user "understand" that "something will be loaded in a while".

When the loading will be finished, you must just make it hidden .

Moreover, if you want to be sure that images will be added after the loading of the view controller itself, load them through the viewWillAppear method, NOT viewDidLoad !

Answer 2

Hope this will help you for background queue and main queue operation !!!!

func bgQueue(queueName: String, completion codeBlock: @escaping ((Bool) -> Void)) {

        DispatchQueue.global(qos: .background).async {
            codeBlock(true)
        }
    }

func mainQueue(codeBlock: @escaping ((Bool) -> Void)){
        DispatchQueue.main.async {
            codeBlock(true)
        }
    }

Answer 3

don't load image in ViewDidLoad()

use this to load image

DispatchQueue.main.async {

}