App on iOS device ignores changes in Xcode

Hello, oo explain the problem I give a short example. I created a new project in Swift language. Then I wrote only one line code in the viewDidLoad-method:

view.backgroundColor = .green

When I run the app on my iPhone6 device for the first time you see a green screen. As far as good. Then I change my code in

view.backgroundColor = .red

When I run it again instead of a red screen there is still the green screen. Any changes in my code are ignored (on a iOS simulator there is no problem!). I restarted Xcode again and also I did Cmd shift K but neither of them helped. I am grateful for any help.


(Xcode 11.0, iphone6 iOS 12.4.9, MacOS Majove 10.14.6)

Hi Eddi,

I don’t have Xcode 11 anymore so can’t try it out. Have you considered updating both your MacOS version and also updating Xcode?

I guess it depends on how old your Mac is and if a later macOS version will run on it.

What model and year is your Mac? You can find out by selecting the Apple symbol on the menu and then choosing “About This Mac”. You will get a window similar to this one.

Hello Chris,
I dont want update my Mac because I use a music software which can not run on Catalina.

Bildschirmfoto 2020-11-29 um 12.26.38

Ah right.

If you reboot your machine and then open that project in Xcode again then run it on your iPhone 6, does it still refuse to reflect that you changed the colour?

Still refuse.
I figured out when I delete some other selfmade apps then it works. I am confused.
You think the source of my problem is that i use Xcode without paying the annualy money to apple?

Try to restart your computer and your phone, and then quit Xcode. it it does not work. Delete the app in your phone and then try again. You can also use TestFlight, made by Apple. It does not matter if you have a Apple Developer Account.