connormurray7 connormurray7 - 1 year ago 146
Swift Question

NSCollectionView Grid of Files Displayed with Icons from Finder's Preview

I am having trouble trying to create an NSCollectionView with icons that are taken from Finder's icon preview.

Ideally, if the file is a dmg it should display the hard drive icon, an mp3 should be the mp3 icon and a photo should display what the photo looks like itself.

There is one post that addresses this issue:
Is it possible to get programmatic access to finder preview images?

But the code is old and does not compile. I am also using Swift in this project.

I used this post to setup a template for my project:
Is there a way to set up a NSCollectionView programmatically in Swift?

Which adds a subview to NSView. If this can be modified to implement the icons, that would be ideal.

In addition I am using a NSFileManager.defaultManager to get the contents of a folder, and would like to display those contents in the collection view.

I am new to developing on the Mac platform and have more experience with iOS, specific answers are much appreciated, thanks!

Answer Source

Update, I was able to figure out how to use what Finder uses with the Quicklook library that Apple provides. Here is part of the code that I used. Note that if you are trying to use Quicklook on a file that does not have a preview, then there will be an error, so in those cases I just used the iconForFile function (below this code block)

let tmp = QLThumbnailImageCreate(kCFAllocatorDefault, tmpURL , CGSize(width: 64, height: 64), nil)
tmpImage = tmp.takeUnretainedValue()
tmpIcon = NSImage(CGImage: tmpImage!, size: NSSize(width: 64, height: 64))


I was able to find (almost) what I was looking for.

In the NSWorkspace class there is a method

func iconForFile(_ fullPath: String) -> NSImage

That will return an NSImage of the icon. Unfortunately, I do not see a way to get a preview of the image if it is a picture. Nor do I see a way to make the picture larger (only 32x32 pixels).

Hopefully this answer will help others that encounter this problem!

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