Coredata fetching concept - ios

Question

Hello i am just creating an sample project in which i have Login and signup class.i created a signup class with all textfields and registered it successfully with coredata.The problem is i need to get the registered user into login class to make it successfull into next page.i have to check whether the user exist or not in my Login class.
Signup.m
#implementation CoreSignup
#synthesize managesObjectContext=_managesObjectContext;
#synthesize managesObjectModel=_managesObjectModel;
#synthesize persistentStoreCoordinator=_persistentStoreCoordinator;
#pragma mark Insert Row In CoreData
-(void)insertSignUpList:(NSMutableDictionary *)details_Ary
{
BOOL isInserted=[self insertRowForSignUp:[details_Ary valueForKey:#"Firstname"] Lastname:[details_Ary valueForKey:#"Lastname"] password:[details_Ary valueForKey:#"Password"] emailid:[details_Ary valueForKey:#"Emailid"] phoneNo:[details_Ary valueForKey:#"Phoneno"] city:[details_Ary valueForKey:#"City"]];
if (isInserted)
{
//inserted Successfully
NSLog(#"inserted Successfully");
}
}
-(BOOL)insertRowForSignUp:(NSString *)firstName Lastname:(NSString *)LastName password:(NSString *)password emailid:(NSString *)emailid phoneNo:(NSString *)phoneNo city:(NSString *)city{
AppDelegate *appDelegate =[[UIApplication sharedApplication] delegate];
NSManagedObjectContext *context =
[appDelegate managedObjectContext];
SignUp *signUpInfo=[NSEntityDescription insertNewObjectForEntityForName:#"SignUp" inManagedObjectContext:context];
signUpInfo.firstName=firstName;
signUpInfo.lastName=LastName;
signUpInfo.password=password;
signUpInfo.phoneno=#([phoneNo intValue]);
signUpInfo.city=city;
signUpInfo.emailid=emailid;
NSError *error;
if (![context save:&error]) {
NSLog(#"Oops coudnt save");
return NO;
}
return YES;
}
-(NSMutableArray*)fetchAll{
AppDelegate *appDelegate =[[UIApplication sharedApplication] delegate];
NSManagedObjectContext *context =
[appDelegate managedObjectContext];
NSFetchRequest *request=[[NSFetchRequest alloc]init];
NSEntityDescription *entity1=[NSEntityDescription entityForName:#"SignUp" inManagedObjectContext:context];
[request setEntity:entity1];
NSArray *emptyArray=[self.managesObjectContext executeFetchRequest:request error:nil];
NSMutableArray *AllHistory=[NSMutableArray new];
for (SignUp*signUpHistory in emptyArray) {
NSMutableDictionary *tempDict=[[NSMutableDictionary alloc]init];
[tempDict setObject:[NSString stringWithFormat:#"%#",signUpHistory.firstName] forKey:#"firstname"];
[tempDict setObject:[NSString stringWithFormat:#"%#",signUpHistory.lastName] forKey:#"lastName"];
[tempDict setObject:[NSString stringWithFormat:#"%#",signUpHistory.password] forKey:#"password"];
[tempDict setObject:[NSString stringWithFormat:#"%#",signUpHistory.emailid] forKey:#"emailid"];
[tempDict setObject:[NSString stringWithFormat:#"%#",signUpHistory.city] forKey:#"city"];
[tempDict setObject:[NSString stringWithFormat:#"%#",signUpHistory.phoneno] forKey:#"phoneno"];
[AllHistory addObject:tempDict];
}
return AllHistory;
}
Login.m
#interface ViewController ()<UITextFieldDelegate>
#end
#implementation ViewController
#synthesize JJuser;
#synthesize JJpassword;
#synthesize managesObjectContext=_managesObjectContext;
#synthesize managesObjectModel=_managesObjectModel;
#synthesize persistentStoreCoordinator=_persistentStoreCoordinator;
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[self jjtext];
[self jjpass];
}
-(void)jjtext{
JJuser.delegate=self;
[JJuser enableMaterialPlaceHolder:YES];
}
-(void)jjpass{
JJpassword.delegate=self;
[JJpassword enableMaterialPlaceHolder:YES];
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField{
[textField resignFirstResponder];
return YES;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
-(NSMutableArray*)fetchLogin{
AppDelegate *appDelegate =[[UIApplication sharedApplication] delegate];
NSManagedObjectContext *context =
[appDelegate managedObjectContext];
NSFetchRequest *request=[[NSFetchRequest alloc]init];
NSEntityDescription *entity1=[NSEntityDescription entityForName:#"SignUp" inManagedObjectContext:context];
[request setEntity:entity1];
NSArray *emptyArray=[self.managesObjectContext executeFetchRequest:request error:nil];
NSMutableArray *AllHistory=[NSMutableArray new];
for (SignUp*signUpHistory in emptyArray) {
NSMutableDictionary *tempDict=[[NSMutableDictionary alloc]init];
[tempDict setObject:[NSString stringWithFormat:#"%#",signUpHistory.firstName] forKey:#"firstname"];
[tempDict setObject:[NSString stringWithFormat:#"%#",signUpHistory.lastName] forKey:#"lastName"];
[tempDict setObject:[NSString stringWithFormat:#"%#",signUpHistory.password] forKey:#"password"];
[tempDict setObject:[NSString stringWithFormat:#"%#",signUpHistory.emailid] forKey:#"emailid"];
[tempDict setObject:[NSString stringWithFormat:#"%#",signUpHistory.city] forKey:#"city"];
[tempDict setObject:[NSString stringWithFormat:#"%#",signUpHistory.phoneno] forKey:#"phoneno"];
[AllHistory addObject:tempDict];
}
return AllHistory;
}
- (IBAction)Login:(id)sender {
AppDelegate *appDelegate =[[UIApplication sharedApplication] delegate];
NSManagedObjectContext *context =
[appDelegate managedObjectContext];
NSFetchRequest *FindIt=[[NSFetchRequest alloc]init];
NSEntityDescription *entity1=[NSEntityDescription entityForName:#"SignUp" inManagedObjectContext:context];
[FindIt setEntity:entity1];
NSPredicate *pred = [NSPredicate predicateWithFormat:[NSString stringWithFormat:#"firstName = \"%#\"",FindIt]];
[FindIt setPredicate:pred];
NSUInteger count = [context countForFetchRequest:FindIt error:nil];
if (count == NSNotFound)
{
UIAlertView*alert=[[UIAlertView alloc]initWithTitle:#"Hello" message:#"No Such id exist" delegate:self cancelButtonTitle:#"Ok" otherButtonTitles:nil, nil];
[alert show];
}else if (count == 1)
{
}
else{
}
}
- (IBAction)Signup:(id)sender
{
UIStoryboard *board = [UIStoryboard storyboardWithName:#"Main" bundle:nil];
SignUpViewController*SignUp = [board instantiateViewControllerWithIdentifier:#"SignUp"];
[self.navigationController pushViewController:SignUp animated:YES];
}
#end

Answer 1

You can use a Fetch Request for checking whether the user is already present and if present then if the passwords match
Try this and tell me if it works
-(BOOL)searchDatabaseForUser:(NSString *)username andPassword:(NSString *)password{
AppDelegate *appDelegate =[[UIApplication sharedApplication] delegate];
NSManagedObjectContext *context = [appDelegate managedObjectContext];
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:#"EntityName"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"username = %#",username];
[fetchRequest setPredicate:predicate];
NSError *error = nil;
NSArray *result = [context executeFetchRequest:fetchRequest error:&error];
if([result count]){
for (NSManagedObject *obj in result) {
if([[obj valueForKey:#"password"]isEqualToString:password]){
return YES;
}
}
return NO;
//passwords doesnt match even though username found
}
else {
return NO;
// No such Username found
}
}
Now call this method as to where you want to validate the user should to the next screen or not, Like this
Login.m
-(IBAction)someButtonToCheckLogin:(id)sender{
BOOL shouldUserLogin = [self searchDatabaseForUser:UserNameTextField.txt andPassword:passwordTextField.txt];
if(shouldUserLogin){
//navigate to the next screen.
}
else {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Title of the application" message:#"Password mismatch, Please check again" delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil, nil];
[alert show];
}
I guess this is pretty self explainable. Hope this helps you to understand.