Project Files and Groups

Open TrailLog's Project navigator and you see a tree of files you did not write: an asset catalogue, a plist, two storyboards, delegates. Each has one job. Knowing them means you know where every change belongs.

The rule

The project describes how to build; targets say what to build; files hold the pieces.

At the top of the Project navigator is the project (the blue icon). Clicking it shows its targets. A target is one product to build — the TrailLog app, its unit tests, maybe a widget later — each with its own build settings, signing and list of files.

The template creates these for a UIKit app:

• TrailLog.xcodeproj — the project package on disk. It stores targets, build settings and the file list. A .xcworkspace groups several projects together, for example when dependencies live in their own project.
• AppDelegate.swift — marked @main; the app's entry point. Handles app-wide events like launch.
• SceneDelegate.swift — manages one window (a scene): setting it up and reacting when it goes to the background.
• ViewController.swift — the first screen's code.
• Main.storyboard — the first screen's layout. LaunchScreen.storyboard — the still image shown while the app starts.
• Assets.xcassets — the asset catalogue: app icon, images and named colours.
• Info.plist — key–value settings the system reads, such as usage descriptions ("TrailLog uses your location to record routes"). Many of these now appear in the target's Info tab instead of a separate file.

A SwiftUI template swaps the delegates and storyboard for a TrailLogApp.swift file marked @main and a ContentView.swift.

Groups are the folders in the navigator. Traditionally a group was just a label inside the project file and did not have to match the folders on disk. Recent Xcode versions (16 and later) create folders synchronised with disk: add a file to the folder in Finder and it joins the project automatically. Either way, group by feature — Hikes, Map, Settings — rather than by kind of file.

The shortcut

For any change, ask "Is it code, a picture, a system setting, or a build setting?"

The trap is editing build settings on the wrong target — changing the test target when you meant the app.

Drills

Answer fast — trust the rule.

Remember

• The project describes how to build; each target is one product; files hold the pieces.
• Shortcut: code, picture, system setting or build setting — each has its home.
• Group by feature, and check which target you are editing.