How to enable Dark Mode for Xcode [duplicate]

Answer 1

On macOS 10.13 High Sierra and earlier

The Dark Mode is only available on macOS 10.14 Mojave.

On macOS 10.14 Mojave and later

1. On Installation: You'll get asked for the appearance as part of the installation of Mojave.

2. After Installation: If you want to change it afterwards go to System Preferences > General and change the Appearance.

2b. On macOS Catalina: You get even a third option to change the appearance automatically based on your Nightshift preferences.

Answer 2

If you use macOS Mojave (10.14.+), you can enable Dark Mode only for Xcode 10 using this command line.

defaults write com.apple.dt.Xcode NSWindowDarkChocolate -bool true

Workaround:

defaults write com.apple.dt.Xcode _NSSystemAppearanceOverride DarkAppearance

Source (Steve Troughton-Smith's tweet)