OSXUIUtils

OSXUIUtils.h

#pragma once

#ifdef __APPLE__

struct OSXUIUtils
{
    static void setDarkTheme(void* view);

};

#endif

OSXUIUtils.mm

#include "OSXUIUtils.h"

#import <AppKit/AppKit.h>

void OSXUIUtils::setDarkTheme(void* view)
{
	NSView* nsView = (NSView*)view;
	NSWindow* nsWindow = [nsView window];

    NSAppearance* appearance = [NSAppearance appearanceNamed:NSAppearanceNameVibrantDark];
    [nsWindow setAppearance:appearance];
}

Usage from a JUCE app:

        mainWindow.reset (new MainWindow (getApplicationName()));

#if JUCE_MAC
        auto* windowHandle = mainWindow->getWindowHandle();
        OSXUIUtils::setDarkTheme(windowHandle);
#endif