我有一个带有核心数据项目的情节提要，其中包含 1 个名为“Password”的实体和 4 个字符串属性，数据通过 fecthedResultsController 连接到表视图，并且这些部分由称为“type”的属性之一设置。
当我启动我的应用程序时，一切正常，我可以添加、更新和删除，没有任何问题。即使当我离开应用程序进入主屏幕并返回时，也没有任何反应。问题是当我从多任务菜单关闭应用程序并重新启动它时，我会在相同数量的好单元格中得到空单元格。它们被分组在顶部，没有部分。
我究竟做错了什么？
插入视图控制器.m
-(IBAction)insertPassword:(id)sender
{
NSInteger row;
NSString*subTypeSelectd=[[NSString alloc]init];
row = [pickerSubjects selectedRowInComponent:0];
subTypeSelectd = [arrSubSubjects objectAtIndex:row];
NSInteger row2;
NSString*TypeSelectd=[[NSString alloc]init];
row2 = [pickerSubjects selectedRowInComponent:1];
TypeSelectd = [arrSubject objectAtIndex:row2];
// self.insertPassword.desc=self.txtDesc.text;
// self.insertPassword.userName=self.txtUserName.text;
// self.insertPassword.password=self.txtPassword.text;
// self.insertPassword.type=TypeSelectd;
// self.insertPassword.subType=subTypeSelectd;
// NSLog(@"insertPassword");
// [self.delegete addPasswordViewControllerDidSave];
AppDelegate *delegate = [UIApplication sharedApplication].delegate;
NSManagedObjectContext *addViewcontrollerLocalContext = delegate.managedObjectContext;
NSManagedObject*password=[NSEntityDescription insertNewObjectForEntityForName:@"Password" inManagedObjectContext:addViewcontrollerLocalContext];
[password setValue:self.txtDesc.text forKey:@"desc"];
[password setValue:self.txtUserName.text forKey:@"userName"];
[password setValue:self.txtPassword.text forKey:@"password"];
[password setValue:subTypeSelectd forKey:@"subType"];
[password setValue:TypeSelectd forKey:@"type"];
NSError*error;
if(![addViewcontrollerLocalContext save:&error])
NSLog(@"input %@",error);
else NSLog(@"saved");
[self.navigationController popViewControllerAnimated:YES];
}
和 mainViewController.m
-(void)addPasswordViewControllerDidSave
{
NSManagedObjectContext*context=self.manageObjectContext;
NSError*error;
if(![context save:&error])
NSLog(@"error : %@",error);
NSLog(@"addPasswordViewControllerDidSave");
[self.navigationController popViewControllerAnimated:YES];
}
-(void)addPasswordViewControllerDidDelete:(Password *)passwordToDelete
{
NSLog(@"B");
NSManagedObjectContext*context=self.manageObjectContext;
[context deleteObject:passwordToDelete];
[self.navigationController popViewControllerAnimated:YES];
}
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if([[segue identifier]isEqualToString:@"addPassword"])
{
insertViewController*ipvc=(insertViewController*)[segue destinationViewController];
Password*p=(Password*)[NSEntityDescription insertNewObjectForEntityForName:@"Password" inManagedObjectContext:[self manageObjectContext]];
// ipvc.delegete=self;
ipvc.insertPassword=p;
}
if([[segue identifier]isEqualToString:@"updatePassword"])
{
updateViewController*uvc=(updateViewController*)[segue destinationViewController];
NSIndexPath*indexPath=[self.tableView indexPathForSelectedRow];
Password*p=[self.fecthedResultsController objectAtIndexPath:indexPath];
uvc.updatePassword=p;
}
}
//-------------------------------------------------------------table------------
-(NSFetchedResultsController*)fecthedResultsController
{
if(fecthedResultsController!=nil)
return fecthedResultsController;
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Password"
inManagedObjectContext:[self manageObjectContext]];
[fetchRequest setEntity:entity];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"type" ascending:YES];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
fecthedResultsController=[[NSFetchedResultsController
alloc]initWithFetchRequest:fetchRequest managedObjectContext:[self manageObjectContext]
sectionNameKeyPath:@"type" cacheName:nil];
fecthedResultsController.delegate=self;
return fecthedResultsController;
}
-(void)controllerWillChangeContent:(NSFetchedResultsController *)controller
{
[self.tableView beginUpdates];
[self.tableView reloadData];
}
-(void)controllerDidChangeContent:(NSFetchedResultsController *)controller
{
[self.tableView endUpdates];
}
-(void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject
atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type
newIndexPath:(NSIndexPath *)newIndexPath
{
UITableView*tableview=self.tableView;
switch (type) {
case NSFetchedResultsChangeInsert:
[tableview insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath]
withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeDelete:[tableview deleteRowsAtIndexPaths:[NSArray
arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeUpdate:{
Password*p=[self.fecthedResultsController objectAtIndexPath:indexPath];
UITableViewCell*cell=[tableview cellForRowAtIndexPath:indexPath];
cell.textLabel.text=p.userName;
cell.detailTextLabel.text=p.password;
// cell.imageView.image=[UIImage imageWithData: p.photodata];
}
break;
case NSFetchedResultsChangeMove:
[tableview deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath]
withRowAnimation:UITableViewRowAnimationFade];
[tableview insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath]
withRowAnimation:UITableViewRowAnimationFade];
break;
default:
break; }}
-(void)controller:(NSFetchedResultsController *)controller didChangeSection:
(id<NSFetchedResultsSectionInfo>)sectionInfo atIndex:(NSUInteger)sectionIndex forChangeType:
(NSFetchedResultsChangeType)type
{
switch (type) {
case NSFetchedResultsChangeInsert:
[self.tableView insertSections:[NSIndexSet indexSetWithIndex:sectionIndex]
withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeDelete:[self.tableView deleteSections:[NSIndexSet
indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
default:
break;
} }
-(NSString*)tableView:(UITableView *)tableView titleForHeaderInSection:
(NSInteger)section
{
return [[[self.fecthedResultsController sections]objectAtIndex:section]name];
}
- (void)tableView:(UITableView *)tableView commitEditingStyle:
(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
if (editingStyle == UITableViewCellEditingStyleDelete) {
NSManagedObjectContext*context=[self manageObjectContext];
Password*passwordToDelete=[self.fecthedResultsController objectAtIndexPath:indexPath];
[context deleteObject:passwordToDelete];
NSError*error;
if(![context save:&error])
NSLog(@"error");
} }
//-------------------------------------------------------------table-end-----------
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
// Custom initialization
}
return self;
}
-(void)viewWillApear
{
}
- (void)viewDidLoad
{
[super viewDidLoad];
NSError*error;
if(![[self fecthedResultsController]performFetch:&error])
{
NSLog(@"ERROR");
abort();
}
// Uncomment the following line to preserve selection between presentations.
// self.clearsSelectionOnViewWillAppear = NO;
// Uncomment the following line to display an Edit button in the navigation bar for this view controller.
// self.navigationItem.rightBarButtonItem = self.editButtonItem;
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
//#warning Potentially incomplete method implementation.
// Return the number of sections.
NSLog(@"%i",[[self.fecthedResultsController sections]count]);
return [[self.fecthedResultsController sections]count];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
//#warning Incomplete method implementation.
// Return the number of rows in the section.
id<NSFetchedResultsSectionInfo>secInfo=[[self.fecthedResultsController
sections]objectAtIndex:section];
return [secInfo numberOfObjects];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
// Configure the cell...
NSLog(@"cell");
Password*p=[self.fecthedResultsController objectAtIndexPath:indexPath];
cell.textLabel.text=p.userName;
cell.detailTextLabel.text=p.password;
// if(p.photodata!=nil)
// cell.imageView.image=[UIImage imageWithData: p.photodata];
return cell;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return 60;
}