Classes/EditingViewController.m

/*
     File: EditingViewController.m
 Abstract: The table view controller responsible for editing a field of data -- either text or a date.
  Version: 1.5
 
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 */
 
#import "EditingViewController.h"
 
@interface EditingViewController ()
 
@property (nonatomic, weak) IBOutlet UITextField *textField;
@property (nonatomic, weak) IBOutlet UIDatePicker *datePicker;
 
@property (nonatomic, readonly, getter=isEditingDate) BOOL editingDate;
 
@end
 
 
#pragma mark -
 
@implementation EditingViewController
{
    BOOL _hasDeterminedWhetherEditingDate;
    BOOL _editingDate;
}
 
#pragma mark - View lifecycle
 
- (void)viewDidLoad
{
    // Set the title to the user-visible name of the field.
    self.title = self.editedFieldName;
}
 
 
- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    
    // Configure the user interface according to state.
    if (self.editingDate) {
        
        self.textField.hidden = YES;
        self.datePicker.hidden = NO;
        NSDate *date = [self.editedObject valueForKey:self.editedFieldKey];
        if (date == nil) {
            date = [NSDate date];
        }
        self.datePicker.date = date;
    }
    else {
        
        self.textField.hidden = NO;
        self.datePicker.hidden = YES;
        self.textField.text = [self.editedObject valueForKey:self.editedFieldKey];
        self.textField.placeholder = self.title;
        [self.textField becomeFirstResponder];
    }
}
 
 
#pragma mark - Save and cancel operations
 
- (IBAction)save:(id)sender
{
    // Set the action name for the undo operation.
    NSUndoManager * undoManager = [[self.editedObject managedObjectContext] undoManager];
    [undoManager setActionName:[NSString stringWithFormat:@"%@", self.editedFieldName]];
    
    // Pass current value to the edited object, then pop.
    if (self.editingDate) {
        [self.editedObject setValue:self.datePicker.date forKey:self.editedFieldKey];
    }
    else {
        [self.editedObject setValue:self.textField.text forKey:self.editedFieldKey];
    }
    
    [self.navigationController popViewControllerAnimated:YES];
}
 
 
- (IBAction)cancel:(id)sender
{
    // Don't pass current value to the edited object, just pop.
    [self.navigationController popViewControllerAnimated:YES];
}
 
 
#pragma mark - Manage whether editing a date
 
- (void)setEditedFieldKey:(NSString *)editedFieldKey
{
    if (![_editedFieldKey isEqualToString:editedFieldKey]) {
        _hasDeterminedWhetherEditingDate = NO;
        _editedFieldKey = editedFieldKey;
    }
}
 
 
- (BOOL)isEditingDate
{
    if (_hasDeterminedWhetherEditingDate == YES) {
        return _editingDate;
    }
    
    NSEntityDescription *entity = [self.editedObject entity];
    NSAttributeDescription *attribute = [entity attributesByName][self.editedFieldKey];
    NSString *attributeClassName = [attribute attributeValueClassName];
    
    if ([attributeClassName isEqualToString:@"NSDate"]) {
        _editingDate = YES;
    }
    else {
        _editingDate = NO;
    }
    
    _hasDeterminedWhetherEditingDate = YES;
    return _editingDate;
}
 
 
@end