bdunagan

fill the void - bdunagan

25 Sep 2010
Cocoa Tip: Enabling "Launch on Startup"

When I start up my Mac, I have a number of apps launch, including Jing, Evernote, LaunchBar, and BusySync. Each registers itself as a “Login Item”, listed in System Preferences under Accounts. Developers have different names for this option, like “Launch on Startup” or “Launch at Login”.

In 10.4 and older, Mac OS X enabled this feature through AppleScript, and Apple has sample code for that in LoginItemsAE. In 10.5 and 10.6, the API is in LSSharedFileList.h, buried in the LaunchServices framework:

/System/Library/Frameworks/CoreServices.framework/ Frameworks/LaunchServices.framework/Headers/

I played around with this API a bit today and came up with a couple wrapper methods to abstract away the details: isLaunchAtStartup and toggleLaunchAtStartup:. Feel free to use this code.

// MIT license
- (BOOL)isLaunchAtStartup {
// See if the app is currently in LoginItems.
LSSharedFileListItemRef itemRef = [self itemRefInLoginItems];
// Store away that boolean.
BOOL isInList = itemRef != nil;
// Release the reference if it exists.
if (itemRef != nil) CFRelease(itemRef);

return isInList;
}

- (IBAction)toggleLaunchAtStartup:(id)sender {
// Toggle the state.
BOOL shouldBeToggled = ![self isLaunchAtStartup];
// Get the LoginItems list.
LSSharedFileListRef loginItemsRef = LSSharedFileListCreate(NULL, kLSSharedFileListSessionLoginItems, NULL);
if (loginItemsRef == nil) return;
if (shouldBeToggled) {
// Add the app to the LoginItems list.
CFURLRef appUrl = (CFURLRef)[NSURL fileURLWithPath:[[NSBundle mainBundle] bundlePath]];
LSSharedFileListItemRef itemRef = LSSharedFileListInsertItemURL(loginItemsRef, kLSSharedFileListItemLast, NULL, NULL, appUrl, NULL, NULL);
if (itemRef) CFRelease(itemRef);
}
else {
// Remove the app from the LoginItems list.
LSSharedFileListItemRef itemRef = [self itemRefInLoginItems];
LSSharedFileListItemRemove(loginItemsRef,itemRef);
if (itemRef != nil) CFRelease(itemRef);
}
CFRelease(loginItemsRef);
}

- (LSSharedFileListItemRef)itemRefInLoginItems {
LSSharedFileListItemRef itemRef = nil;
NSURL *itemUrl = nil;

// Get the app's URL.
NSURL *appUrl = [NSURL fileURLWithPath:[[NSBundle mainBundle] bundlePath]];
// Get the LoginItems list.
LSSharedFileListRef loginItemsRef = LSSharedFileListCreate(NULL, kLSSharedFileListSessionLoginItems, NULL);
if (loginItemsRef == nil) return nil;
// Iterate over the LoginItems.
NSArray *loginItems = (NSArray *)LSSharedFileListCopySnapshot(loginItemsRef, nil);
for (int currentIndex = 0; currentIndex < [loginItems count]; currentIndex++) {
// Get the current LoginItem and resolve its URL.
LSSharedFileListItemRef currentItemRef = (LSSharedFileListItemRef)[loginItems objectAtIndex:currentIndex];
if (LSSharedFileListItemResolve(currentItemRef, 0, (CFURLRef *) &itemUrl, NULL) == noErr) {
// Compare the URLs for the current LoginItem and the app.
if ([itemUrl isEqual:appUrl]) {
// Save the LoginItem reference.
itemRef = currentItemRef;
}
}
}
// Retain the LoginItem reference.
if (itemRef != nil) CFRetain(itemRef);
// Release the LoginItems lists.
[loginItems release];
CFRelease(loginItemsRef);

return itemRef;
}
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