ios - Swift:线程中的 URLRequest

Question

我想从 url 获取数据，但在过程完成之前，我想显示加载图标

我使用此代码但不适合我

DispatchQueue.global(qos: .background).async {
    // show loading icon
    // start get data
    DispatchQueue.main.async {
        // remove loading icon
    }
}

Answer 1

来自 UIView

Threading Considerations

Manipulations to your application’s user interface must occur on themain thread. Thus, you should always call the methods of the UIViewclass from code running in the main thread of your application. Theonly time this may not be strictly necessary is when creating the viewobject itself but all other manipulations should occur on the mainthread.

这意味着您可能应该在主线程中显示/隐藏和操作您的 View ，而不是像在“显示加载 View ”中那样在后台线程中进行操作。