UIWindow 在方法完成之前不显示

Posted 2023-02-23

【中文标题】UIWindow 在方法完成之前不显示

【英文标题】：UIWindow not displaying until method complete

【发布时间】：2016-10-20 18:11:10

【问题描述】：

我正在尝试显示一个视图，因为该方法需要几秒钟才能完成。但是，直到整个方法完成，加载的 UIWindow 才真正成为关键和可见的。知道这里发生了什么吗？

// this line creates a uiwindow with view controller as root view controller, an activity indicator, and a label and makes the loading view key and visible
[XSELLoadingView presentLoadingViewWithTitle:@"Generating Report"]; // use loading view for long times

// these three lines process a lot of data and present the view on the main window
XSELCount *startCount = [[XSELCount counts] objectAtIndex:[self.startingPick selectedRowInComponent:0]];
XSELCount *endCount = [[XSELCount counts] objectAtIndex:[self.endingPick selectedRowInComponent:0
[self.navigationController pushViewController:[XSELReportView viewWithReportData:[XSELReportData compareStartCount:startCount toEndCount:endCount]] animated:false];   

// this line makes the main view key and visable 
[XSELLoadingView dismissLoadingView];

【问题讨论】：

只是为了澄清 XSELLoadingView 确实显示了一个带有视图的窗口，而不仅仅是当前窗口顶部的视图。

您需要在后台进行长处理。

【参考方案1】：

在这个里面应用你的任务。

 dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^
    //Do background work
    dispatch_async(dispatch_get_main_queue(), ^
        //Update UI
    );
);