objective c - iOS: Global property variable not being set even when value is passed to it -

i have set of code parses xml file find user id number. id number sent view controller soap wsdl request. problem value never set.

my 2 classes loginpageviewcontroller , emimenutableviewcontroller.

i trying pass integer value loginpageviewcontroller emimenutableviewcontroller.

here header file emimenutableviewcontroller:

#import <uikit/uikit.h> @interface emimenutableviewcontroller : uitableviewcontroller @property (nonatomic) int usernumber; @end 

here header file loginpageviewcontroller:

#import <uikit/uikit.h>  @interface loginpageviewcontroller : uiviewcontroller <nsxmlparserdelegate>  {     nsxmlparser *xmlparser;      nsstring *classelement;     nsmutablearray *titarry;     nsmutablearray *linkarray;     bool itemselected;     nsmutablestring *mutttitle;     nsmutablestring *mutstrlink;     int usernumber;     nsstring *parsedstring; }  // username , password text fields @property (weak, nonatomic) iboutlet uitextfield *usernametextfield; @property (weak, nonatomic) iboutlet uitextfield *passwordtextfield;  // logging in , registering - (ibaction)loginbuttonselected:(id)sender; @property (weak, nonatomic) iboutlet uibutton *registerbutton;  // unwind segue ibaction logging out - (ibaction)logoutandunwind:(uistoryboardsegue *)segue;  @end  

here value set in loginpageviewcontroller:

- (void)parserdidenddocument:(nonnull nsxmlparser *)parser { emimenutableviewcontroller *controller = [[emimenutableviewcontroller alloc] init]; // if user authenticated, allow them proceed segue if([parsedstring containsstring:@"user authenticated"]) {      >>>controller.usernumber = usernumber<<<; - set here     nslog(@"user:%d", usernumber);     [self performseguewithidentifier:@"login_success" sender:self];     nslog(@"logged in");      // if server says user isn't found, notify user create account. } else if([parsedstring containsstring:@"user not found"]) {      uialertview *alert = [[uialertview alloc] initwithtitle:@"user not found" message:@"please create account!" delegate:self cancelbuttontitle:@"close" otherbuttontitles:nil, nil];     [alert show];      // if server replies password incorrect, notify user. } else if([parsedstring containsstring:@"password incorrect"]) {      uialertview *alert = [[uialertview alloc] initwithtitle:@"incorrect username/password" message:@"plese try again." delegate:self cancelbuttontitle:@"close" otherbuttontitles:nil, nil];     [alert show];  } else {      uialertview *alert = [[uialertview alloc] initwithtitle:@"an error has occurred!" message:@"please check network connection , try again." delegate:self cancelbuttontitle:@"close" otherbuttontitles:nil, nil];     [alert show];  }  } 

here code shows value isn't being set (this in emimenutableviewcontroller):

nslog(@"user: %d", _usernumber); 

also, here console output. can see value set in loginpageviewcontroller logged it, when logged in emimenutableviewcontroller, 0.

2015-07-08 15:09:41.151 emi[1971:173596] user:27808 2015-07-08 15:09:41.179 emi[1971:173596] logged in 2015-07-08 15:09:41.186 emi[1971:173596] user: 0 

i figured doing right, can't figure out wrong. setting variable wrong?

thanks.

this line...

emimenutableviewcontroller *controller = [[emimenutableviewcontroller alloc] init]; 

creates emimenutable vc, , line

controller.usernumber = usernumber; 

sets property on it. controller lives milliseconds. released arc when goes out of scope.

meanwhile, performsegue creates new copy of emimenutablevc, , 1 never gets chance hear usernumber found in parse.

so need value parse conveyed segue's destination view controller. simple way of doing declare usernumber property of loginvc also, e.g.

@interface loginpageviewcontroller : uiviewcontroller <nsxmlparserdelegate> // ... // more formal emimenutable vc, equivalent... @property (nonatomic, assign) nsinteger usernumber; 

with that, parser shouldn't build own emimenutable vc. set property on self...

if([parsedstring containsstring:@"user authenticated"]) {     // ...     self.usernumber = usernumber;     // ...     [self performseguewithidentifier:@"login_success" sender:self]; 

now, implement prepare segue, , set value on destination vc.

edit - changed understanding segue points navigation view controller...

// sure import #import "emimenutableviewcontroller.h" - (void)prepareforsegue:(uistoryboardsegue *)segue sender:(id)sender {     if ([segue.identifier isequaltostring:@"login_success"]) {         uinavigationcontroller *navvc = (uinavigationcontroller *)segue.destinationviewcontroller;         emimenutableviewcontroller *vc = (emimenutableviewcontroller *)navvc.viewcontrollers[0];         //         vc.usernumber = self.usernumber;     } } 

a funkier approach misuse sender: parameter of performsegue. can skip instance variable loginvc, , pass value directly this...

[self performseguewithidentifier:@"login_success" sender:@(usernumber)]; 

this weird, because performsegue sender number. work, since type generic id. prepare method looks same, except...

    if ([segue.identifier isequaltostring:@"login_success"]) {         uinavigationcontroller *navvc = (uinavigationcontroller *)segue.destinationviewcontroller;         emimenutableviewcontroller *vc = (emimenutableviewcontroller *)navvc.viewcontrollers[0];         nsnumber *paramtrick = (nsnumber *)sender;         vc.usernumber = [paramtrick intvalue];     } 

but guess don't recommend way, if you're starting out.