QLPreviewController not displays saved file

Question

I'm getting this behaviour using Xcode 8.0. The problem is, after downloading a file and storing it on documents directory (code provided below), QLPreviewController only displays document's name and size. The property currentPreviewItem returns the correct path document. What's even more strange, is that if I try to open that document from another controller in my app, it works fine. I've implemented both QLPreviewControllerDelegate and QLPreviewControllerDataSource.

Code for downloading and saving document:

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
    NSURL *url = [NSURL URLWithString:file[@"url"]];

    NSData *data = [NSData dataWithContentsOfURL:url];

    if (!data) {
        completion([NSError new]);
        return;
    }

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

    NSString *path = [[paths objectAtIndex:0] stringByAppendingPathComponent:AppName];
    path = [path stringByAppendingPathComponent:file[@"name"]];

    file[@"filePath"] = [NSURL fileURLWithPath:path];

    dispatch_async(dispatch_get_main_queue(), ^{
        [[NSFileManager defaultManager] createFileAtPath:path contents:data attributes:nil];
        completion(nil);
    });
});

Then, when user selects a document I use the content saved on @"filePath" to show QLPreviewController. I've tried pushing it and presenting it modally and in both cases it just displays a gray page with document's name and size.

Could you upload your project to github? and so I can know the detail,thanks. — aircraft, Sep 28 '16 at 09:42
@QQ726535609 Hello, I can't share the project because it's not personal. However, if you can tell me which information you need I'll provide it to you. Thanks! — Borja Pérez Guasch, Sep 28 '16 at 11:40
If you're sure that the contents downloaded are valid, you should probably file a radar on bugreport.apple.com — Raffael, Sep 28 '16 at 12:05
@ThomasDeniau apparently that was the problem. Some of downloaded files don't include their extension in filename, so QLViewController can't open the file. If I add manually the extension, the file is shown correctly. — Borja Pérez Guasch, Sep 28 '16 at 15:19

score 0 · Answer 1 · answered Sep 28 '16 at 15:22

File wasn't showed because downloaded contents didn't contain file's extension. When I tried opening it in other controller, it worked because I temporary used another file name containing the correct extension. So I solved the problem adding the extension .pdf to downloaded files that didn't include it. This made QLViewController displaying correctly the file.

score 0 · Answer 2 · answered Mar 02 '18 at 13:44

0

In my case, a file was created with the correct name, but the file contained an error message from the server, thus not representing the expected file structure.

answered Mar 02 '18 at 13:44

Sjakelien

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QLPreviewController not displays saved file

2 Answers2