My app is literally the default Xcode project with just a button that prints "Working" to the console when pressed. The button works when I first open the app on my phone. The button still works if I exit and then reopen the app, or even turn off my phone and then reopen the app. But when I swipe up to go to the Control Center and then swipe up on my app and then reopen it, the button no longer works. Occasionally (but not every time I have tested), Xcode will say: "Message from debugger: Terminated due to signal 9". What am I doing wrong? Again, the code is just the SwiftUI Project starter code and this:

Button("Click me", action: {
    print("Works")
})

>Solution :

Killing the app while it’s running from Xcode is not a very nice thing to do to Xcode, which becomes confused and is no longer "hooked up" to the running app. You need to unconfuse Xcode:

• You’re not waiting long enough before you "reopen it": after the swipe up, count to ten, slowly, and then relaunch the app from Xcode.

• Another good idea is to check that the app has also stopped in Xcode itself: after the swipe up, switch to Xcode and hit its Stop button, count to three, slowly, then relaunch the app from Xcode.