iOS

Solution: You could simply refetch the coredata entities for unsaved changes. But you can restart the app the unsaved changes will be discarded.So you must have to save the changes. But you changed in persistant store with current context then the changes will be available in before saving.You can try the rollback context to discard the last changes. Also undomanager available in coredata.You could try that to start the changes and rollback to the particular point....

Solution: In coredata if you tried rollback then the current context will be rolled back.But if you tried with global context it will never works.So you have try that in cancel you will rollback after comeback to that screen you have to do another rollback in viewDidload. Then it will works good

Problem: I had tried to set the size for item zero but it not sets properly.For that it returns sized value. collection View(_: layout: size For Item At:)              let  newSize =  my Array . count   >   0  ?  CGSize (width: width / 3 , height: width / 3 ) :  CGSize (width:  0 , height:  0 ) return  newSize Solution: Because in apple they already said that you must have to set the size value to be non zero.              let  newSize =  my Array . count   >   0  ?  CGSize (width: width / 3 , height: width / 3 ) :  CGSize (width:  0.5 , height:  0.5 ) return  newSize Use the above code it will works good.