I am trying use CoreData, but when I add it to my project I only get two new methods :
- (NSPersistentContainer *)persistentContainer
and
- (void)saveContext
Now I can't get old methods to work with CoreData, and I can't find any tutorials with these new methods and Objective-C. How can I save and get data from CoreData using persistentContainer in Xcode 8 with Objective-c?
You can Get context as -
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
or as in Objective-C
NSManagedObjectContext *context = ((AppDelegate*)[[UIApplication sharedApplication] delegate]).persistentContainer.viewContext;
And fetch data like -
var resultArray = try self.context.fetch(EntityName.fetchRequest())
or as in Objective-C
NSFetchRequest<EntityName *> *fetchRequest = [EntityName fetchRequest];
NSError *error ;
NSArray *resultArray= [context executeFetchRequest:fetchRequest error:&error];
And fetch data with sorting -
var resultArray = [EntityName]()
do {
let request : NSFetchRequest<EntityName> = EntityName.fetchRequest()
let sortDescriptor = NSSortDescriptor(key: "somekey", ascending: true)
let sortDescriptors = [sortDescriptor]
request.sortDescriptors = sortDescriptors
resultArray = try self.context.fetch(request)
} catch {
print("Error")
}
or as in Objective-C
NSFetchRequest<EntityName *> *fetchRequest = [EntityName fetchRequest];
NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"someKey" ascending:YES];
fetchRequest.sortDescriptors = @[sortDescriptor];
NSError *error ;
NSArray *resultArray= [context executeFetchRequest:fetchRequest error:&error];
And add data like -
let entityNameObj = EntityName(context: context)
entityNameObj.title = "title"
or as in Objective-C
NSManagedObject *entityNameObj = [NSEntityDescription insertNewObjectForEntityForName:@"EntityName" inManagedObjectContext:context];
[entityNameObj setValue:@"someValue" forKey:@"someKey"];
And save context like -
do {
try self.context.save()
} catch _ as NSError {
print("Error")
}
or as in Objective-C
[((AppDelegate*)[[UIApplication sharedApplication] delegate]) saveContext];
-(void)profileDatabase
{ NSManagedObjectContext* context=[ADM.persistentContainer viewContext];
NSManagedObject *profile=[NSEntityDescription insertNewObjectForEntityForName:@"Profile" inManagedObjectContext:context];
[profile setValue:[self.serverResponseOfProfileDict objectForKey:@"firstName"] forKey:@"firstName"];
[profile setValue:[self.serverResponseOfProfileDict objectForKey:@"surName"] forKey:@"surName"];
[profile setValue:[self.serverResponseOfProfileDict objectForKey:@"batchID"] forKey:@"batchID"];
[profile setValue:[self.serverResponseOfProfileDict objectForKey:@"profileImagePath"] forKey:@"profileImagePath"];
[profile setValue:[self.serverResponseOfProfileDict objectForKey:@"registeredEmail"] forKey:@"registeredEmail"];
[profile setValue:[self.serverResponseOfProfileDict objectForKey:@"role"] forKey:@"role"];
[profile setValue:[self.serverResponseOfProfileDict objectForKey:@"studentID"] forKey:@"studentID"];
NSLog(@"userObj:%@",profile);
NSError* error;
[context save:&error];
NSFetchRequest *fetchRequest=[[NSFetchRequest alloc]initWithEntityName:@"Profile"];
fetchRequest.returnsObjectsAsFaults=NO;
NSArray* results=[context executeFetchRequest:fetchRequest error:&error];
NSLog(@"Result:%@",results);
NSManagedObject *result=[results objectAtIndex:0];
[ADM.databaseResponseOfProfileDict setObject:[result valueForKey:@"firstName"] forKey:@"firstName"];
[ADM.databaseResponseOfProfileDict setObject:[result valueForKey:@"surName"] forKey:@"surName"];
[ADM.databaseResponseOfProfileDict setObject:[result valueForKey:@"batchID"] forKey:@"batchID"];
[ADM.databaseResponseOfProfileDict setObject:[result valueForKey:@"profileImagePath"] forKey:@"profileImagePath"];
[ADM.databaseResponseOfProfileDict setObject:[result valueForKey:@"registeredEmail"] forKey:@"registeredEmail"];
[ADM.databaseResponseOfProfileDict setObject:[result valueForKey:@"role"] forKey:@"role"];
[ADM.databaseResponseOfProfileDict setObject:[result valueForKey:@"studentID"] forKey:@"studentID"];
NSLog(@"dic:%@",ADM.databaseResponseOfProfileDict);
}
scorpio
I have found a solution using Objective C. It runs, but I'm not sure that it is the correct solution.
- (void)dbManager {
NSManagedObjectContext *context = self.persistentContainer.viewContext;
NSError *error = nil;
if ([context hasChanges] && ![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.
NSLog(@"Unresolved error %@, %@", error, error.userInfo);
abort();
}
NSManagedObject *customAnimal = [NSEntityDescription insertNewObjectForEntityForName:@"Animals" inManagedObjectContext:context];
[customAnimal setValue:@"Lion" forKey:@"type"];
[customAnimal setValue:@"Rabit" forKey:@"name"];
[customAnimal setValue:@"Blue" forKey:@"color"];
[customAnimal setValue:@12 forKey:@"age"];
NSLog(@"Get data from DB");
NSMutableArray* animalsArray;
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:@"Animals"];
animalsArray = [[context executeFetchRequest:fetchRequest error:nil] mutableCopy];
NSLog(@"array is %@", animalsArray); // array is (
"<Animals: 0x6000000aee80> (entity: Animals; id: 0x60000022e120 <x-coredata:///Animals/tAAC7332D-6BEF-441C-9041-0ECB57469FA62> ; data: {\n age = 12;\n color = Blue;\n name = Rabit;\n type = Lion;\n})"
}
For all the beginners out there, this will give you the basic idea.
welcome.m
==========
#import "welcomepage.h"
#import "Register.h"
#import "login.h"
#import "AppDelegate.h"
#import "Student+CoreDataProperties.h"
#import "loginbtn.h"
#import "King+CoreDataProperties.h"
@interface welcomepage ()
{
AppDelegate *a;
NSManagedObjectContext *context;
}
@end
@implementation welcomepage
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
}
- (IBAction)login:(id)sender
{
loginbtn *lb=[[loginbtn alloc]init];
[self.navigationController pushViewController:lb animated:YES];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)register:(id)sender
{
a=(AppDelegate *)[UIApplication sharedApplication].delegate;
NSManagedObjectContext *context1=((AppDelegate *)[UIApplication sharedApplication].delegate).persistentContainer.viewContext;
Student *ss=[NSEntityDescription insertNewObjectForEntityForName:@"Student" inManagedObjectContext:context1];
ss.name=[NSString stringWithFormat:@"%@",_txtfld1.text];
ss.age=[NSString stringWithFormat:@"%@",_txtfld2.text];
ss.place=[NSString stringWithFormat:@"%@",_txtfld3.text];
[a saveContext];
if (_txtfld1.text.length && _txtfld2.text.length && _txtfld3.text.length != 0)
{
UIAlertView *al=[[UIAlertView alloc]initWithTitle:@"THANK YOU" message:@"DATA SUCESSFULLY SAVER. YOU CAN LOGIN NOW WITH YOUR PASSWORD AND NAME" delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil];
[al show];
_txtfld1.text=@"";
_txtfld2.text=@"";
_txtfld3.text=@"";
Register *rg=[[Register alloc]init];
[self.navigationController pushViewController:rg animated:YES];
}
else
{
UIAlertView *al2=[[UIAlertView alloc]initWithTitle:@"WARRNING" message:@"PLEASE FILL THE DATA COMPLETELY" delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil];
[al2 show];
}
}
===================================================
Register.m
==========
#import "Register.h"
#import "AppDelegate.h"
#import "Student+CoreDataProperties.h"
#import "welcomepage.h"
@interface Register ()<UITableViewDelegate,UITableViewDataSource>
{
AppDelegate *a;
NSManagedObjectContext *context01;
NSArray *array01;
}
@end
@implementation Register
- (void)viewDidLoad
{
[super viewDidLoad];
a=((AppDelegate *)[UIApplication sharedApplication].delegate);
context01=((AppDelegate *)[UIApplication sharedApplication].delegate).persistentContainer.viewContext;
// specifying nsrequest and nsentity
NSFetchRequest *req=[[NSFetchRequest alloc]init];
NSEntityDescription *entity01=[NSEntityDescription entityForName:@"Student" inManagedObjectContext:context01];
[req setEntity:entity01];
// putting datas from reto array
NSError *err=nil;
array01=[context01 executeFetchRequest:req error:&err];
// Do any additional setup after loading the view from its nib.
}
-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return array01.count;
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return 3;
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *ci=@"hai";
UITableViewCell *cell=[tableView dequeueReusableCellWithIdentifier:ci];
if (cell==nil) {
cell=[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:ci];
}
if (indexPath.row==0) {
cell.textLabel.text=[[array01 objectAtIndex:indexPath.section]valueForKey:@"name"];
}
if (indexPath.row==1) {
cell.textLabel.text=[[array01 objectAtIndex:indexPath.section]valueForKey:@"age"];
}
if (indexPath.row==2) {
cell.textLabel.text=[[array01 objectAtIndex:indexPath.section]valueForKey:@"place"];
}
return cell;
}
==================================================
Loginbtn.m
============
#import "loginbtn.h"
#import "AppDelegate.h"
#import "Student+CoreDataProperties.h"
#import "login.h"
@interface loginbtn ()
{
AppDelegate *a;
NSArray *arraylb;
}
@end
@implementation loginbtn
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)lgbtn:(id)sender
{
a=(AppDelegate *)[UIApplication sharedApplication].delegate;
//xcode 8.2.1 specification code
NSManagedObjectContext *context=((AppDelegate *)[UIApplication sharedApplication].delegate).persistentContainer.viewContext;
//creating feathch request and entity
NSFetchRequest *req=[[NSFetchRequest alloc]init];
NSEntityDescription *entity=[NSEntityDescription entityForName:@"Student" inManagedObjectContext:context];
[req setEntity:entity];
// setting predicate
NSPredicate *pre=[NSPredicate predicateWithFormat:@"age like %@ and place like %@",_txt1.text,_txt2.text];
[req setPredicate:pre];
//creating error and array to store
NSError *err=nil;
arraylb=[[NSArray alloc]init];
arraylb=[context executeFetchRequest:req error:&err];
login *lg=[[login alloc]init];
if (arraylb.count!=0)
{
lg.array001=arraylb;
}
//
// if (arraylb.count!=0)
//// {
////
//// lv *lvi=[[lv alloc]init];
////
//// //passing value
//// lvi.array001=arraylb;
////
////
//// //lv.str1=self.tf1.text;
//// //lv.str2=self.tf2.text;
//// [self.navigationController pushViewController:lvi animated:YES];
////
////
//// }
//// else
//// {
//
// self.lb.text=@"Invalid username & password";
//
// }
//
[self.navigationController pushViewController:lg animated:YES];
}
=====================================================
Lohin.m
=========
#import "login.h"
#import "Student+CoreDataProperties.h"
#import "AppDelegate.h"
#import "loginbtn.h"
@interface login ()
{
AppDelegate *a;
NSArray *array01;
}
@end
@implementation login
- (void)viewDidLoad
{
[super viewDidLoad];
_txt11.text=[[_array001 objectAtIndex:0]valueForKey:@"name"];
_txt22.text=[[_array001 objectAtIndex:0]valueForKey:@"age"];
_txt33.text=[[_array001 objectAtIndex:0]valueForKey:@"place"];
// Do any additional setup after loading the view from its nib.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
// Dispose of any resources that can be recreated.
}
来源：https://stackoverflow.com/questions/41040253/how-to-use-coredata-in-xcode-8