Using the Console to Debug SwiftUI Apps

Written by Team Kodeco

When developing a SwiftUI app, you may sometimes encounter unexpected behavior or bugs. Like other IDEs, Xcode provides a console to help you troubleshoot these issues. You can use the console to print messages and display logs from your app.

One way to use the console for debugging is with Swift’s Logger framework. Logger() lets you log messages about your app’s behavior, specify the severity of these messages and add custom data to help understand your app’s state.

Here’s an example where you have a button in your SwiftUI app, and it’s expected to display an alert when tapped. If the alert doesn’t appear, you can use the Logger to log an informational message to check if the button’s action closure is being executed:

import SwiftUI
import os

struct ContentView: View {
  @State private var showAlert = false
  let logger = Logger()

  var body: some View {
    Button("Show Alert") {
      logger.info("Button tapped")
      showAlert = true
    }
    .alert(isPresented: $showAlert) {
      Alert(title: Text("Important Message"))
    }
  }
}

Run the app in your simulator, then tap the Show Alert button. Go back to Xcode and your screen should look like this:

Aha — the text “Button tapped” has been logged to the console by the Logger! This allows you to verify that the code is executing as expected.

Using Swift’s Logger to log messages at different log levels and with various privacy settings, you can gain a better understanding of your app’s behavior at runtime and diagnose issues more effectively. You can access the console via the View ▸ Debug Area ▸ Activate Console menu option or by using the keyboard shortcut Command-Shift-C.