CODEWITHSUNDEEP
iphoneiosweb-servicesipaddelegates
Sam
Sam

Reputation: 41

How can my main view controller know when the web service call finished

Hi I have an web service based app that will interchange data with our server. Since I have a dedicated class doing my work, the main view controller will actually call the worker every time. The worker itself knows when the connection finished since it is a NSURLConnectionDelegate. However I need to inform the main view controller whenever the work is done. The worker is a delegate of main view controller so it knows when it need to start working. Please help me.

Upvotes: 0

Views: 280

Answers (4)

8Ours
8Ours

Reputation: 132

You can do it in two ways:

Approach #1:

User Local notifications. In the mainclass add an observer into LocalNotification Center in following way.

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(jobDone) name:@"WORKERJOBOVER" object:nil];

And in the worker class when the job is done, post nofitication to fire the selector:

[[NSNotificationCenter defaultCenter] postNotificationName:@"WORKERJOBOVER" object:nil];

Approach #2:

You can create a protocol of your worker class and add a method in the protocol which you can call on the delegate when your job is done in worker.

WorkerClass.h

//WorkerClass.h

@protocol WorkerDelegate

@interface WorkerClass: NSObject

@property (nonatomic, assign) id<WorkerDelegate> delegate

- (void)JobInProcess;
@end


@protocol WorkerDelegate
- (void)MyJobIsDone;
@end

WorkerClass.m

//WorkerClass.m

@implementation WorkerClass
@synthesize delegate = _delegate;

- (void)JobInProcess
{
    //When job over this will fire callback method in main class
    [self.delegate MyJobIsDone];
}

MainClass.h

    //MainClass.h
#import WorkerClass.h

@interface MainClass: NSObject <WorkerDelegate>


@end

MainClass.m

//MainClass.m

@implementation MainClass

- (void)MyJobIsDone
{
    //Do whatever you like
}
@end

Upvotes: 2

Shane
Shane

Reputation: 667

I would fire a notification from the background worker that you can listen for from your main view controller

In your View add the following when you want to listen.

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(operationComplete:) name:@"operationComplete" object:nil];

In your background View notify that the event completed.

[[NSNotificationCenter defaultCenter] postNotificationName:@"operationComplete" object:nil];

Finally don't forget to remove the observer [[NSNotificationCenter defaultCenter] removeObserver:self];

Upvotes: 0

Raymond Wang
Raymond Wang

Reputation: 1484

You should do the other way around.

First declare your worker object as a member of your main view controller(and of course, make it a property), then from you main view controller, you can just call [self.worker sendRequstToServer] to send the request.

Second, within your main view controller, wherever you initialize your work object, don't forget to put self = worker.delegate.

Third, declare a delegate method in your worker class, something like -(void)webServiceCallFinished(), and call [self.delegate webServiceCallFinished] in your worker's -connectionDidFinishLoading() (you might wanna do in -parserDidEndDocument() if you are using NSXMLParer to parse xml)

Last, you wanna declare your main view controller as the delegate of your worker class and implement -webServiceCallFinished().

Hope this helps.

Upvotes: 2

lobianco
lobianco

Reputation: 6276

In viewDidLoad: of your main view controller, set it as a notification observer with [NSNotificationCenter defaultCenter]:

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(webServiceContacted:) name:@"webServiceConnectionSuccessful" object:nil];

Then when your data was successfully interchanged with the server, post a notification within the network completion block:

[[NSNotificationCenter defaultCenter] postNotificationName:@"webServiceConnectionSuccessful" object:nil];

And webServiceContacted: could look like this:

-(void)webServiceContacted:(NSNotification *)note
{
    //do stuff here
}

Upvotes: 1

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