tailieunhanh - more iphone 3 development phần 4

Trong Chương 4, chúng tôi sẽ mở rộng ứng dụng của chúng tôi hơn nữa và thêm mã để cho phép người dùng chỉnh sửa dữ liệu siêu anh hùng của họ. Hãy xem ở Hình 3-1 để có được một cảm giác về những gì ứng dụng của chúng tôi sẽ giống như khi nó chạy. Trông rất giống như các ứng dụng mẫu. | CHAPTER 6 Custom Managed Objects 155 a call to the superclass s validateAndPop method. When you re done the save method should look like this - IBAction save NSUInteger oniyRow 0 0 NSIndexPath onlyRowPath NSIndexPath indexPathWithIndexes onlyRow length 2 UITableViewCell cell cellForRowAtIndexPath onlyRowPath UITextField textField UITextField viewWithTag kTextFieldTag setValue forKey self validateAndPop Save . Updating ManagedObjectDateEditor Next single-click and do the same thing. When you re done it should look like this - IBAction save setValue forKey self validateAndPop Save . Updating ManagedObjectSingleSelectionListEditor Finally single-click and repeat the process one more time. When you re done the save method should look like this - IBAction save UITableViewCell selectedCell cellForRowAtIndexPath lastIndexPath NSString newValue setValue newValue forKey self validateAndPop Save . Creating the Value Transformer Earlier in the chapter we added an attribute called favoriteColor and set its type to Transformable. As we stated then often you ll be able to leave the transformable attribute s transformer class at NSKeyedUnarchiveFromData and be completely done with the process since that provided class will use an NSKeyedArchiver to convert an object instance into an NSData object that can be stored in the persistent store and an NSKeyedUnarchiver to take the NSData object from the persistent store and reconstitute it back into an object instance. 156 CHAPTER 6 Custom Managed Objects In the case of UlColor we can t do that because UlColor doesn t conform to NSCoding and can t be archived using an .