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所以我有一個實用程序的應用程序，我試圖將一些文本保存到Flipside View Controller的「To」和「Message：」文本字段中，但是我的數據不會保存。客觀C和我一直在使用多個不同的教程的地步，我已經完全糊塗了我自己。希望你能幫助我。不知道還有什麼在這一點上做的......核心數據問題。數據不會保存
FlipsideViewController.m
#import "CCCFlipsideViewController.h"
#import "CCCAppDelegate.h"
#import "CCCMainViewController.h"
#import "MessageDetails.h"
@interface CCCFlipsideViewController()
{
// NSManagedObjectContext *context;
}
@end
@implementation CCCFlipsideViewController
@synthesize allMessageDetails;
@synthesize managedObjectContext;
- (void)awakeFromNib
{
[super awakeFromNib];
CCCAppDelegate *appDelegateController = [[CCCAppDelegate alloc]init];
self.managedObjectContext = appDelegateController.managedObjectContext;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription
entityForName:@"MessageDetails" inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];
NSError *error;
self.allMessageDetails = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];
/*
NSManagedObject *managedObject; = [_fetchedResultsController valueForKey:@"to"];
self.toTextField.text = managedObject to;
messageDetails.to = [allMessageDetails firstObject];
self.toTextField.text = messageDetails.to;
messageDetails.message = [allMessageDetails valueForKey:@"message"];
self.messageTextField.text = messageDetails.message;
*/
NSLog(@"The 'to' is currently at %@ after viewdidload", self.toTextField.text);
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
return [textField resignFirstResponder]; //function says that if (bool) the text field is open and the keyboard hits return, text field is to resign first responder.
}
#pragma mark - Actions
- (IBAction)done:(id)sender
{
[self.delegate flipsideViewControllerDidFinish:self];
}
- (IBAction)resignFirstResponder:(id)sender {
[self.toTextField resignFirstResponder];
[self.messageTextField resignFirstResponder];
NSLog(@"Resigned First Responder");
}
- (IBAction)save:(id)sender {
// Create a new instance of the entity managed by the fetched results controller.
NSManagedObjectContext *context = [self.fetchedResultsController managedObjectContext];
NSEntityDescription *entity = [[self.fetchedResultsController fetchRequest] entity];
NSManagedObject *newManagedObject = [NSEntityDescription insertNewObjectForEntityForName:[entity name] inManagedObjectContext:context];
// If appropriate, configure the new managed object.
[newManagedObject setValue:self.toTextField.text forKey:@"to"];
[newManagedObject setValue:self.messageTextField.text forKey:@"message"];
// Save the context.
NSError *error = nil;
if (![context save:&error]) {
/*
Replace this implementation with code to handle the error appropriately.
abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. If it is not possible to recover from the error, display an alert panel that instructs the user to quit the application by pressing the Home button.
*/
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
}
}
#pragma mark -
#pragma mark Fetched results controller
- (NSFetchedResultsController *)fetchedResultsController {
if (_fetchedResultsController != nil) {
return _fetchedResultsController;
}
/*
Set up the fetched results controller.
*/
// Create the fetch request for the entity.
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
// Edit the entity name as appropriate.
NSEntityDescription *entity = [NSEntityDescription entityForName:@"MessageDetails" inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];
// Set the batch size to a suitable number.
[fetchRequest setFetchBatchSize:20];
// Edit the sort key as appropriate.
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"to" ascending:NO];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
// Edit the section name key path and cache name if appropriate.
// nil for section name key path means "no sections".
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:@"Root"];
aFetchedResultsController.delegate = self;
self.fetchedResultsController = aFetchedResultsController;
NSError *error = nil;
if (![_fetchedResultsController performFetch:&error]) {
/*
Replace this implementation with code to handle the error appropriately.
abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. If it is not possible to recover from the error, display an alert panel that instructs the user to quit the application by pressing the Home button.
*/
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
}
return _fetchedResultsController;
}
@end
您的NSlog在保存功能中是否打印任何內容？ –
當我在頁面上時，它會告訴我「到」文本字段中的內容。但是，只要我切換到主視圖控制器並回來，到文本字段顯示爲空... –
我問的是，當您調用save：函數時，任何記錄到控制檯，像一個錯誤的描述？ –