Try to set an icon to a file in Cocoa - macos

Question

I try to get a file icon and to set it back to the same file (goal is to have overlay, but I first want to have this one work):
NSImage *img=[[NSWorkspace sharedWorkspace] iconForFile:#"MyFilePath"];
NSLog(#"x=%.f",img.size.width); // Result=32
[[NSWorkspace sharedWorkspace] setIcon:img forFile:#"MyFilePath" options:0];
-> Result is that my file gets a standard Finder icon instead of keeping its own icon. Anything I am doing wrong ?

Answer 1

Try using it like this:
[[NSWorkspace sharedWorkspace]
setIcon: [[NSImage alloc] initWithContentsOfFile:#"MyFilePath"]
forFile: #"MyFilePath"
options: 0];
You need to to load the icon/image into memory first.
EDIT: Answer updated to provide additional information in regards to
the comment below.
"how can I keep the image in memory to "play" with it before reassigning it?"
The NSImage that gets allocated into memory from your specified path can be manipulated in just about any possible way once it's been loaded. You'll want to thoroughly read the NSImage Class Reference to gain a real understanding of what it does and how use it's methods. For this particular scenario you'll want to be able have a named variable assigned from the icon you load.
Only one change needs to happen with the code above to make it work:
NSImage *iconImage = [[NSImage alloc] initWithContentsOfFile:#"MyFilePath"];
[[NSWorkspace sharedWorkspace]
setIcon: iconImage
forFile: #"MyFilePath"
options: 0];
NSLog(#"iconImage: %#",iconImage);
The slight change essentially assigns the variable iconImage from the NSImage icon; everything else stays the same. The NSLog will give you a very quick glimpse at properties associated with iconImage — where you take it from there is really up to your coding ability and creativity.