#protocol on IOS parsing data 2 way? - iphone

Question

I have login Code like this :
#protocol LoginDelegate
-(void)DUsername:(NSString *) username DPassword:(NSString *) password;
#end
#interface loginipad : UIViewController {
id<LoginDelegate> delegate;
IBOutlet UITextField *edusername;
IBOutlet UITextField *edpassword;
}
and then i use this object on mainViewController like this :
#interface mainViewController : UIViewController<LoginDelegate> {
and call this methode on mainViewController
-(void)DUsername:(NSString *) username DPassword:(NSString *) password{
userlogin=[username retain];
passlogin=[password retain];
if (!scm.isRunning) {
[scm connectToHost:#"localhost" onPort:8080];
}
}
This method is success to parsing data from login modalview to mainViewController, but i want show progress of process or any message from mainViewController to login modal view when login button is klick (i try MBPrgoressHUD but no success due i use this login on modal view).
My Question how i can parsing data from mainViewController to This login modalview ?
Thanks,
for call the method :
loginipad *plogin = [[loginipad alloc] initWithNibName:#"loginipad" bundle:nil];
plogin.delegate = self;
UINavigationController *nc = [[UINavigationController alloc] initWithRootViewController:plogin];
plogin.title=#"Login";
[self presentModalViewController:nc animated:YES];
[nc release];
nc = nil;
[plogin release];
plogin = nil;

Answer 1

answer completely edited
Your question leads to multiple solutions and strategies.
First: general posibilities to implement bidirectional data-transfer between two classes.
via multiple protocols: loose cupling but leads to import-loops which are annoying. I know ho to solve import loops for class-definitions (#class) but I dont know how to solve this for protocols
A.h:
#import "B.h"
#protocol ADelegate
-(void) adelegate:(NSString*)data;
#end
#interface A : NSObject<BDelegate>
{
id<ADelegate> delegate;
}
#end
B.h:
#import "A.h"
#protocol BDelegate
-(void) bdelegate:(NSString*)data;
#end
#interface B : NSObject<ADelegate>
{
id<BDelegate> delegate;
}
#end
via a single protocol: dense cupling :( but no import-loop (this is a working ugly style)
A.h:
//no import here needed
#protocol ADelegate
-(void) adelegate:(NSString*)data;
#end
#interface A : NSObject<BDelegate>
{
id<ADelegate> delegate;
}
#end
B.h:
#import "A.h"
#interface B : NSObject<ADelegate>
{
A* delegate;
}
#end
via pipe/stream: bidirectional data-transfer should by done using a pipe (unbuffered) or stream (buffered)
here I show you a small and simple delegate-pipe but there also exists a NSPipe/NSStream
DelegatePipe.h
#protocol DelegatePipeDelegate
- dataArrived:(NSString*)data;
#end
#interface DelegatePipe : NSObject {
NSMutableArray *delegates;
}
-(void)open:(id<DelegatePipeDelegate>)d;
-(void)close:(id<DelegatePipeDelegate>)d;
-(void)send:(NSString*)data;
#end
DelegatePipe.m
#implementation DelegatePipe
-(id)init
{
if(self = [super init])
{
delegates = [NSMutableArray array];
}
return self;
}
-(void) dealloc
{
[delegates release];
delegates = nil;
}
-(void) open:(id <DelegatePipeDelegate>)d
{
#synchronized(self)
{
if([delegates containsObject:d])
return;
//if([delegates count]>=2) //Pipe contains originally only 2 delegates. but a broadcaster is also nice ;)
// return;
[delegates addObject:d];
}
}
-(void) close:(id <DelegatePipeDelegate>)d
{
#synchronized(self)
{
[delegates removeObject:d];
}
}
-(void) send:(NSString *)data
{
#synchronized(self)
{
for(id<DelegatePipeDelegate> d in delegates)
[d dataArrived:data];
}
}
#end
Second: KVO
KVO is often used in a ModelViewController (MVC) Pattern. eg: visualize data in a view. The network-connection-state in your case is part of data and your loginipad is a view (and a controller)
Authentificator.h
typedef enum eAuthState
{
NOT_CONNECTED = 0,
LOGIN_FAILED,
CONNECING,
CONNECTED
} AuthState;
#interface Authentificator : NSObject {
AuthState state;
}
#property (nonatomic, assign) AuthState state;
#end
Authentificator.m
...
-(void) doAuthWithUsername:(NSString*)name password:(NSString*)pw
{
self.state = CONNECING;
//do network-stuff
}
//delegate from network. here NSURLConnection
-(void) connectionDidFinishLoading:(NSURLConnection *)connection
{
//parse network-answer
BOOL success = YES;
if(success)
self.state = CONNECTED;
else
self.state = LOGIN_FAILED;
}
loginipad.h
#interface loginipad : UIViewController
{
Authentificator *auth;
}
#property (nonatomic, retain) Authentificator *auth;
#end
loginipad.m
#implementation loginipad
#synthesize auth;
//override setter for more comfortable use (add/removeObserver)
-(void) setAuth:(Authentificator *)a
{
#synchronized(auth)
{
[auth removeObserver:self forKeyPath:#"state"];
[auth release];
auth = a;
[auth retain];
[auth addObserver:self forKeyPath:#"state" options:0 context:nil];
}
}
-(IBAction) buttonClicked:(id)aSender
{
self.auth = [Authentificator sharedAuthentificator];
}
-(void) observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
if(![object isKindOfClass:Authentificator.class])
return;
AuthState state = ((Authentificator*)object).state;
NSLog(#"curState: %i",state);
//do sth with state
}
- (void)dealloc {
self.auth = nil;
[super dealloc];
}