То, что вы ищете, это «NSOpenPanel», вот пример использования:
NSOpenPanel *panel = [NSOpenPanel openPanel];
[panel setCanChooseFiles:NO];
[panel setCanChooseDirectories:YES];
[panel setAllowsMultipleSelection:YES]; // yes if more than one dir is allowed
NSInteger clicked = [panel runModal];
if (clicked == NSFileHandlingPanelOKButton) {
for (NSURL *url in [panel URLs]) {
// do something with the url here.
}
}