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POPattern for preloading data for subsequent view to be displayed
 

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    <p>Very simple use case: Let's say an iOS app displays a <code>MovieListController</code> view (inside of a <code>UINavigationController</code>) with a list of movies. When the user touches on one, the app pushes a <code>MovieDetailController</code> onto the navigation stack (i.e. <code>[[MovieDetailController alloc] initWithMovieId:(NSString *)</code>. In the <code>MovieDetailController</code>'s <code>viewDidAppear:</code> method, it makes an HTTP call to retrieve details based on the movie ID passed into it. </p> <p>The challenge is that the <code>MovieDetailController</code> gets pushed onto the navigation stack right away, and for a second or two while the details haven't been retrieved, the view shows a bunch of blank fields, which is undesirable.</p> <p>To get around this, I'm thinking of having the <code>MovieListController</code> not push the <code>MovieDetailController</code> onto the stack right away. Instead, it would put up a progress indicator (I'm using SVProgressHUD), then call <code>MovieDetailController</code>'s <code>initWithMovieId:</code> method which would kick off the HTTP call. Then when the data is received, the <code>MovieDetailController</code> would make a callback back to <code>MovieListController</code> to remove the progress indicator and then push the <code>MovieDetailController</code> onto the navigation stack. </p> <p>Is there a better pattern for this type of scenario? Should I be considering having the <code>MovieDetailController</code> push itself onto the navigation stack when it's ready? </p> <p>Note: I have considered loading the detail view and putting up an activity indicator, but you'll still be able to see an 'empty view' behind it which looks a bit weird. I have also considered just having the <code>MovieListController</code> retrieve the details itself but this seems to break the encapsulation model - the <code>MovieListController</code> should just be concerned about listing movies, not about their details.</p> <p>Any thoughts? This Movie stuff is just an example - looking for a general pattern here.</p>
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    1. COSeems to me the latter approach would be less desirable than waiting for the blank view to be filled in. It would give the impression the app was frozen for a few seconds. You could put placeholders up (e.g., a placeholder image for the movie) until the data is received instead of having a blank view.
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    2. COI don't mind putting up an activity view on the table view while data for the detail view is being loaded. I just don't want to move to a blank detail view then display an activity view. But I'm wondering if there's some timing issues here.
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    3. COYou would probably get different answers at http://ux.stackexchange.com/ from UX experts for a question like this.
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