NSMutableArray to NSString and Passing NSString to Another View IOS5.1 - objective-c

Question

I have an NSMutableArray of names. I want the pass the data (selected name) inside of NSMutableArray as text to another view's label.
FriendsController.m:
- (void)viewDidLoad {
[super viewDidLoad];
arrayOfNames=[[NSMutableArray alloc] init];
arrayOfIDs=[[NSMutableArray alloc] init];
userName=[[NSString alloc] init];
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
long long fbid = [[arrayOfIDs objectAtIndex:indexPath.row]longLongValue];
NSString *user=[NSString stringWithFormat:#"%llu/picture",fbid];
[facebook requestWithGraphPath:user andDelegate:self];
userName=[NSString stringWithFormat:#"%#",[arrayOfNames objectAtIndex:indexPath.row]];
FriendDetail *profileDetailName = [[FriendDetail alloc] initWithNibName: #"FriendDetail" bundle: nil];
profileDetailName.nameString=userName;
[profileDetailName release];
}
- (void)request:(FBRequest *)request didLoad:(id)result {
if ([result isKindOfClass:[NSData class]]) {
transferImage = [[UIImage alloc] initWithData: result];
FriendDetail *profileDetailPicture = [[FriendDetail alloc] initWithNibName: #"FriendDetail" bundle: nil];
[profileDetailPicture view];
profileDetailPicture.profileImage.image= transferImage;
profileDetailPicture.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
[self presentModalViewController:profileDetailPicture animated:YES];
[profileDetailPicture release];
}
}
In FriendDetail.h
NSString nameString;
IBOutlet UILabel *profileName;
#property (nonatomic, retain) UILabel *profileName;
#property (nonatomic, retain) NSString *nameString;
In FriendDetail.m
- (void)viewDidLoad
{
[super viewDidLoad];
profileName.text=nameString;
}
nameString in second controller(FriendDetail) returns nil. When i set a breakpoint in firstcontroller I see the string inside of nameString is correct but after that it returns to nil somehow.
-----------------------EDIT----------------------------------------
According to answers I have improved my code little bit
FriendsController.h
FriendDetail *friendController;
#property (strong, nonatomic) FriendDetail *friendController;
FriendsController.m
- (void)viewDidLoad
{
[super viewDidLoad];
arrayOfNames=[[NSMutableArray alloc] init];
arrayOfIDs=[[NSMutableArray alloc] init];
arrayOfThumbnails=[[NSMutableArray alloc] init];
userName=[[NSString alloc] init];
friendController= [[FriendDetail alloc] initWithNibName: #"FriendDetail" bundle: nil];
}
-(void)request:(FBRequest *)request didLoad:(id)result{
if ([result isKindOfClass:[NSData class]])
{
transferImage = [[UIImage alloc] initWithData: result];
friendController.nameString=userName;
[friendController view];
friendController.profileImage.image= transferImage;
friendController.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
[self presentModalViewController:friendController animated:YES];
}
//this is how i take facebook friends list
if ([result isKindOfClass:[NSDictionary class]]){
items = [[(NSDictionary *)result objectForKey:#"data"]retain];
for (int i=0; i<[items count]; i++) {
NSDictionary *friend = [items objectAtIndex:i];
long long fbid = [[friend objectForKey:#"id"]longLongValue];
NSString *name = [friend objectForKey:#"name"];
NSLog(#"id: %lld - Name: %#", fbid, name);
[arrayOfNames addObject:[NSString stringWithFormat:#"%#", name]];
[arrayOfIDs addObject:[NSNumber numberWithLongLong:fbid]];
}
}
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
long long fbid = [[arrayOfIDs objectAtIndex:indexPath.row]longLongValue];
NSString *user=[NSString stringWithFormat:#"%llu/picture",fbid];
userName=[NSString stringWithFormat:#"%#",[arrayOfNames objectAtIndex:indexPath.row]];
[facebook requestWithGraphPath:user andDelegate:self];
[username retain]
}
Now when i select row first time it sends name. When i come back to tableview and select another name it shows the old name.
If I delete [username retain] in didSelectRowAtIndexPath: it still sends nil to nameString
when I set break point at didSelectRowAtIndexPath: at line `
userName=[NSString stringWithFormat:#"%#",[arrayOfNames objectAtIndex:indexPath.row]]`
I can see userName = #"Adam Dart" which is correct
in my second breakpoint at line friendController.nameString=userName; I see that nameString =nil and userName = Variable is not CFString
ARC is set to NO

Answer 1

The value is nil because you did not pass the value in request:didLoad: function.
In function didSelectRowAtIndexPath, You create a local instance of another ViewController and set the value of nameString, but you did not present the view and release the ViewController immediately. You actually do nothing in these few lines of code:
FriendDetail *profileDetailName = [[FriendDetail alloc] initWithNibName: #"FriendDetail" bundle: nil];
profileDetailName.nameString = userName;
[profileDetailName release];
In function request:didLoad:, again you create a local instance of another ViewController with image. But this instance is only local to this function, which means no relation to the one created in didSelectRowAtIndexPath.
What you need to do is, remember the name of clicked row first in didSelectRowAtIndexPath, here you dont have to create the ViewController instance. When the request finish, set both the image and name to the controller and then present it. But you should avoid user from clicking different rows at the same time, because you don't know when the request finish.

Answer 2

You have two instances of FriendDetail called profileDetailPicture. Both of theses profileDetailPicture are not the same. So in your didSelectRowAtIndexPath method, the value that you assigned to the nameString will not be visible/available to the nameString of the profileDetailPicture In the request:(FBRequest *)request didLoad method.
Edit for solution:
Create an iVar or property (profileDetailPicture) in the FriendController.
Only do one allocation in the request:(...) method.
Remove the allocation statement in the didSelectRowAtIndexPath.

Answer 3

Any chance it has to do with the fact that you assign to profileDetailName and then immediately release it?
profileDetailName.nameString=userName;
[profileDetailName release];

Answer 4

You have to allocate the "first_controller" in your "second_controller"
to pass objects such as your string. and you would call the nameString differently.
example:
second_controller.h
#import "first_controller.h"
...
#interface second_controller : UIViewController{
first_controller* firstController;
}
second_controller.m
- (void)viewDidLoad {
[super viewDidLoad];
firstController = [[first_controller alloc] init];
profileName.text = firstController.nameString;
}
Which you'll have to init it correctly, because its two views sharing information.