CODEWITHSUNDEEP
objective-ciosxcode
Andy Hin
Andy Hin

Reputation: 31973

iOS - Single delegate to multiple objects. How to vary behavior?

I have a UIViewController which is also a NSURLConnectionDelegate. As such, it defines behavior such as:

– connection:didReceiveResponse: 
– connection:didReceiveData: 
– connectionDidFinishLoading:

However, in this view I have multiple NSURLConnections which assign it as the delegate. I need to achieve custom behavior in connectionDidFinishLoading: depending on which object is calling the delegate (e.g playing audio vs displaying an image vs opening a link)

What is the correct way to achieve this?

Upvotes: 0

Views: 311

Answers (3)

iDev
iDev

Reputation: 23278

If you have a lot of urlconnections which falls under different categories(say 10 connections out of 5 are for audio, 3 for display image, 2 for opening link etc..), better option is to subclass NSURLConnection and create a custom NSURLConnection class. You can add your own property like a tag to this class. And define your own custom tags to different type of connections. In your UIViewController and delegate methods try to use this subclass object and use this tag property to differentiate between different NSURLConnections.

For eg:-

Create a CustomNSURLConnection file and write,

#define kAudioConnectionTag 100
#define kDisplayConnectionTag 200
#define kOpenURLConnectionTag 300

@interface CustomNSURLConnection : NSURLConnection 

@property (nonatomic) NSInteger tag;

In UIViewController class,

CustomNSURLConnection *audioConnection = [CustomNSURLConnection ...];
audioConnection.tag = kAudioConnectionTag;

CustomNSURLConnection *displayConnection = [CustomNSURLConnection ...];
audioConnection.tag = kDisplayConnectionTag;

CustomNSURLConnection *openURLConnection = [CustomNSURLConnection ...];
audioConnection.tag = kOpenURLConnectionTag;

- (void)connectionDidFinishLoading:(CustomNSURLConnection *)connection{
     if (connection.tag == kAudioConnectionTag) {
           //code
     } else if (connection.tag == kDisplayConnectionTag) {
           //code
     } else {
           //code
     }
}

Upvotes: 0

Hanief Utama
Hanief Utama

Reputation: 54

You could declare each of the connection 

@interface YourViewController
@property (retain, nonatomic) NSURLConnection *audioConnection;
@property (retain, nonatomic) NSURLConnection *anotherConnection;

then, on your connectionDidFinishLoading: method call each connection like this:

- (void)connectionDidFinishLoading:(NSURLConnection *)connection{
     if (connection == audioConnection) {
           //doSomething
     } else if (connection == anotherConnection) {
           //doSomethingElse
     }
}

Upvotes: 1

Nathanial Woolls
Nathanial Woolls

Reputation: 5291

Each of the delegate methods pass in the NSURLConnection as a parameter. Store a reference to your connection in a property and then check the if the connection parameter passed into connectionDidFinishLoading is your audio connection or your image connection etc.

Upvotes: 1

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