Garbage Collection is deprecated. ARC it is now and so we have to update/change our Mac projects. Sometimes this is very easy and, of course, often it is harder. And sometimes it is even impossible.

And sometimes there is a need to provide code for both. This can be done with:

#if !__has_feature(objc_arc)
// retain, release etc. here
#endif

The new iPad has arrived and with it the need to provide Retina optimized images not only for Apps, but for websites as well:

@media only screen and (-webkit-min-device-pixel-ratio: 2) {
background: transparent url(path_to/2x.png);
}

I just revised my very often downloaded MGPreferencePanel code. I guess calling it the Cocoa Preference Window for the lazy ones made it that popular in the first place :–)

The MGPreferencePanel is now ready for Mountain Lion and ARC, so no more retained and autoreleased objects and I’ve also simplified the usage.

Drop the files into your project, provide titles and icons for views and that’s it. As always you can do whatever you want with it – Copyleft and WTFPL, you know.

About the MGPreferencePanel – The Cocoa Preference Window for the lazy ones

There is nothing more annoying than programming a preference-window with selectable toolbar-buttons and automatic resizing.

Most of the solutions you find today are either close to the one programmed by Matt Ball or base on it. Indeed, there are even more complicated ways, doing it.

They are all more or less understandable and customizable. But all have in common that it is annoying and time consuming to add each single subview via a separate nib-file or a separate plists. I know some disagree but I believe that more nibs aren‘t always the best solution. Because more nibs lead to more controller, that leads to more work customizing them, that leads to a more enraged programmer.

This is why I programmed my own solution.

Sure, it is far from being perfect, but you have customized everything in less than thirty two seconds!

You can use it as an inspector-view as well. Best of all: just one nib.

Anything left to be desired? Not for me.

Download MGPreferencePanel (Xcode Project | 10.7+)

Concurrency. And concurrency. And once again: concurrency. The holy grail to writing good Apps. And the hardest part. At least to debug.

The simplest way to performe a task not on the main thread is:

[self performSelectorInBackground:@selector(myConcurrentAction) withObject:nil];

- (void) myConcurrentAction {
NSAutoreleasePool *pool = [NSAutoreleasePool new];

// do whatever needs to be done
// but only all things NOT GUI
// ensure that nothing else tries to access used objects meanwhile


[pool drain];
}

I needed a way to terminate an application from within another without using Apple Script or old Carbon stuff. I finally found this nifty solution:

if ([[NSWorkspace sharedWorkspace] respondsToSelector:@selector(runningApplications)]) {
for (NSRunningApplication *app in [[NSWorkspace sharedWorkspace] runningApplications])
if ([@"Suggestions" isEqualToString:[app localizedName]])
[app terminate];
}

NSValueTransfomers are a very handy solution to store a lots of information in a simple int for example. Combined with bindings one can display text in OS X label colors for example. Something I needed today:

@implementation MGIntToColorTransformer

+ (Class)transformedValueClass {

return [NSColor class];
}

+ (BOOL)allowsReverseTransformation {

return NO;
}

- (id)transformedValue:(id)value {

NSColor *color = nil;

switch ([value intValue]) {
case 0:
color = [NSColor colorWithCalibratedRed:0.298 green:0.298 blue:0.298 alpha:1.000]; // [NSColor blackColor] || [NSColor clearColor]
break;
case 1:
color = [NSColor colorWithCalibratedRed:0.924 green:0.372 blue:0.337 alpha:1.000]; // red
break;
case 2:
color = [NSColor colorWithCalibratedRed:0.907 green:0.628 blue:0.255 alpha:1.000]; // orange
break;
case 3:
color = [NSColor colorWithCalibratedRed:0.845 green:0.771 blue:0.254 alpha:1.000]; // yellow
break;
case 4:
color = [NSColor colorWithCalibratedRed:0.642 green:0.766 blue:0.254 alpha:1.000]; // green
break;
case 5:
color = [NSColor colorWithCalibratedRed:0.335 green:0.599 blue:0.937 alpha:1.000]; // blue
break;
case 6:
color = [NSColor colorWithCalibratedRed:0.712 green:0.522 blue:0.796 alpha:1.000]; // lavender
break;
case 7:
color = [NSColor colorWithCalibratedRed:0.624 green:0.624 blue:0.624 alpha:1.000]; // gray
break;
default:
color = [NSColor colorWithCalibratedRed:0.298 green:0.298 blue:0.298 alpha:1.000];
break;
}

return color;
}

@end

While working on a major update for Diary I was searching for a solution to display the users Address Book picture until I realized that there are a lot of people out there not using it or don’t have assigned one.

But every one has a login picture - even if it is the random default one. And there actually is a way to query it:

CBIdentity *identity = [CBIdentity identityWithName:NSUserName() authority:[CBIdentityAuthority defaultIdentityAuthority]];
[identityView setImage: [identity image]];

// don't forget to include the Collaboration framework

Banging your head against the wall while trying to implement the fullscreen feature in an OS X Lion App and the stupid NSToolbar does not respond to setVisible or doesn’t preserve its state?

You’re not alone!

In most cases this should do the trick:

- (NSApplicationPresentationOptions)window:(NSWindow *)window willUseFullScreenPresentationOptions:(NSApplicationPresentationOptions)proposedOptions {
proposedOptions |= NSApplicationPresentationAutoHideToolbar;

return proposedOptions;
}

Apps on the Mac App Store using in some way a WebView will get rejected if the scrollers do not show up for a moment after the content has been loaded and is not entirely visible. But the (stupid) WebView does not ‘flash’ its scrollers automatically and how to do that is not documented - but there is a solution:

[[[[[sender mainFrame] frameView] documentView] enclosingScrollView] flashScrollers];

One should invoke this in the delegate didFinishLoadForFrame method…