This is a demo for a problem I encountered while developing an iOS app.
This is a very simple app. It has only one view display a simple hello message. There is also a button in the toolbar which triggers the display of a sheet view.
The sheet uses the local State property tmpEvent and displays the value of it’s desc
property. This tmpEvent property is initialised with a default Event. Whenever the toolbar
button is tapped this tmpEvent is getting a new Event assigned before the sheet is
displayed. – And here comes the weird stuff – One would expect that the sheet is displaying
the value of the newly assigned event. But when the sheet is displayed the first time it
shows the text from the default event. On every subsequent presentation of the sheet it
works as expected.
Why is the first presentation different from all others? Why is the value of the tmpEvent
property not the expected new event but the default event on the first time?
Just to be sure that this is not a fluke the sheet is setting tmpEvent to a different value
when getting dismissed, which is of course overwritten once the sheet is triggered again.
The event set by the dismiss closure is never to be seen. (Just as one would expect.)