在macOSObjective-C上的模式更改暗模式，亮模式下以编程方式更新颜色设置

如何解决在macOSObjective-C上的模式更改暗模式，亮模式下以编程方式更新颜色设置

我使用的是macOS，objective-c，而不是iOS。 XCode 12。

在很多视图中，我都设置如下颜色：

self.menuIconBar.wantsLayer = YES;
self.menuIconBar.layer.backgroundColor = [NSColor colorNamed:@"color_gradient_right"].CGColor;

每当用户更改外观时，例如进入深色模式，我希望我的颜色会根据素材资源设置而改变：

很遗憾，没有任何反应。 但：IB中应用的相同颜色会按预期直接更改。仍然我也需要它们以编程方式进行更改。

然后我尝试挂接到通知：

[[NSdistributedNotificationCenter defaultCenter] addobserver:self selector:@selector(appleInterfaceThemeChangednotification:) name:@"AppleInterfaceThemeChangednotification" object:nil];

我收到通知，但是当我再次像上面一样调用相同的代码时，仍然加载了错误的颜色。

self.menuIconBar.layer.backgroundColor = [NSColor colorNamed:@"color_gradient_right"].CGColor;

任何帮助表示赞赏

解决方法

以下示例将根据“系统偏好设置”中的“外观”设置更改自定义视图的背景颜色。可以通过创建objc项目，删除预先存在的App Delegate并用以下代码替换“ main.m”中的代码，在Xcode中运行它：

#import <Cocoa/Cocoa.h>

@interface CustomView : NSView
@end

@implementation CustomView

- (id)initWithFrame:(NSRect)frameRect {
 if ((self = [super initWithFrame:frameRect]) != nil) {
 // Add initialization code here
 }
 return self;
}
 
- (void)drawRect:(NSRect)rect {
}

- (void)viewDidChangeEffectiveAppearance {
 NSLog (@"appearance did change.");
 NSAppearance *changedAppearance = NSApp.effectiveAppearance;
 NSAppearanceName newAppearance = [changedAppearance bestMatchFromAppearancesWithNames:@[NSAppearanceNameAqua,NSAppearanceNameDarkAqua]];
 NSLog (@"new appearance name = %@",newAppearance);
  if([newAppearance isEqualToString:NSAppearanceNameDarkAqua]){
    [[self layer] setBackgroundColor:CGColorCreateGenericRGB( 1.0,0.0,1.0 )];
  } else {
    [[self layer] setBackgroundColor:CGColorCreateGenericRGB( 0.0,1.0,1.0 )];
  }
}

 // Use this if you want 0,0 (origin) to be top,left
 // Otherwise origin will be at bottom,left (Unflipped)
-(BOOL)isFlipped {
  return YES;
}
@end
 
@interface AppDelegate : NSObject <NSApplicationDelegate> {
 NSWindow *window;
}

 - (void) buildMenu;
 - (void) buildWindow;
@end
 
@implementation AppDelegate
   
- (void) buildMenu {
 NSMenu *menubar = [NSMenu new];
 NSMenuItem *menuBarItem = [NSMenuItem new];
 [menubar addItem:menuBarItem];
 [NSApp setMainMenu:menubar];
 NSMenu *appMenu = [NSMenu new];
 NSMenuItem *quitMenuItem = [[NSMenuItem alloc] initWithTitle:@"Quit"
 action:@selector(terminate:) keyEquivalent:@"q"];
 [appMenu addItem:quitMenuItem];
 [menuBarItem setSubmenu:appMenu];
}
 
- (void) buildWindow {
 #define _wndW  600
 #define _wndH  550
 
 window = [[NSWindow alloc] initWithContentRect: NSMakeRect( 0,_wndW,_wndH )
 styleMask: NSWindowStyleMaskTitled | NSWindowStyleMaskMiniaturizable | NSWindowStyleMaskClosable
 backing: NSBackingStoreBuffered defer: NO];
 
 [window center];
 [window setTitle: @"Test window"];
 [window makeKeyAndOrderFront: nil];
 
 // **** CustomView **** //
 CustomView *view = [[CustomView alloc]initWithFrame:NSMakeRect( 20,60,_wndW - 40,_wndH - 80 )];
 [view setWantsLayer:YES];
 [[view layer] setBackgroundColor:CGColorCreateGenericRGB( 0.0,1.0 )];
 [[window contentView] addSubview:view];
 
 // **** Quit btn **** //
 NSButton *quitBtn = [[NSButton alloc]initWithFrame:NSMakeRect( _wndW - 50,10,40,40 )];
 [quitBtn setBezelStyle:NSBezelStyleCircular ];
 [quitBtn setTitle: @"Q" ];
 [quitBtn setAction:@selector(terminate:)];
 [[window contentView] addSubview: quitBtn];
}
 
- (void) applicationWillFinishLaunching: (NSNotification *)notification {
 [self buildMenu];
 [self buildWindow];
}
 
- (void) applicationDidFinishLaunching: (NSNotification *)notification {
}
@end
 
int main() {
 NSApplication *application = [NSApplication sharedApplication];
 AppDelegate *appDelegate = [[AppDelegate alloc] init];
 [application setDelegate:appDelegate];
 [application run];
 return 0;
}