如何在Yosemite中检测暗模式以更改状态栏菜单图标

Question

The status bar app icon has to be changed when dark mode is enabled in Yosemite. How to detect if dark mode has been enabled ? Is there any notification for the same ?

Is it better to display another image or change the alpha value of existing Image ? Need inputs on which is the better way to go ??

Answer 1

You should make use of template images wherever possible because they allow your UI to automatically adapt to changes made by the system (at least when there's not a bug in the system... http://indiestack.com/2014/10/yosemites-dark-mode/ ). But in the case where you might use a custom view in the status bar and cannot take advantage of a template image, you can manually check for dark mode and adapt your UI accordingly.

You can check whether or not dark mode is enabled by retrieving a key from the user's global preferences, like this:

NSDictionary *dict = [[NSUserDefaults standardUserDefaults] persistentDomainForName:NSGlobalDomain];
id style = [dict objectForKey:@"AppleInterfaceStyle"];
BOOL darkModeOn = ( style && [style isKindOfClass:[NSString class]] && NSOrderedSame == [style caseInsensitiveCompare:@"dark"] );

At least for the first release of Yosemite, the key is not present when dark mode is disabled, but the key is present and returns the string value @"Dark" when dark mode is enabled. I added the case insensitive compare because I have seen preference keys change their case between system releases, and this adds a little insurance against that.

To monitor the current state of the setting, you register as an observer of a distributed notification (within an appropriate method), like this:

[[NSDistributedNotificationCenter defaultCenter] addObserver:self selector:@selector(darkModeChanged:) name:@"AppleInterfaceThemeChangedNotification" object:nil];

And you create a method to act as the message selector for the notification, like this:

-(void)darkModeChanged:(NSNotification *)notif
{
    NSLog(@"Dark mode changed");
}

Answer 2

The Status bar icon needs to be a template image. Just set the setTemplate:Yes to NSImage. And when switched to dark mode , the vibrancy should apply.

Answer 3

As noted by bergdesign , you need to observe the system wide notification and read the persistent global domain.

We made a class to simplify handling changes to the Dark Mode settings: https://github.com/weAreYeah/WAYTheDarkSide

It becomes as easy as...

[WAYTheDarkSide welcomeApplicationWithBlock:^{
    // Enabling Dark Mode
    [someWindow setAppearance:[NSAppearance appearanceNamed:NSAppearanceNameVibrantDark]];
    [someVisualEffectView setMaterial:NSVisualEffectMaterialDark];

} immediately:YES];

and

[WAYTheDarkSide outcastApplicationWithBlock:^{
    // Disabling Dark Mode
    [someWindow setAppearance:[NSAppearance appearanceNamed:NSAppearanceNameVibrantLight]];
    [someVisualEffectView setMaterial:NSVisualEffectMaterialLight];

} immediately:YES];

Hope this helps :)