Question

I’m having trouble returning a value to a delegate.

@protocol DataDelegateImage
- (void)failImage;
- (NSData*)successImage;
@end

@property (nonatomic, strong) id <DataDelegateImage> delegateImage;
@property (nonatomic, strong) NSMutableData* d;

And I call my delegates like:

[self.delegateImage failImage];

But now I’m trying to call the success delegate returning the data content, but I think I got something wrong, because the code doesn’t work.

[self.delegateImage successImage:self.d];

Any ideas?

Answer 1

Your passing self.d to your successImage and there is no parameter for you to pass anything to it. If you want to be able to pass something to it then it should be like this

     - (void)successImage:(NSMutableData*)para1;

or

     - (void)successImage:(NSData*)para1;

unless you want something to be returned as well as passing something to it in which cases use

     - (NSData*)successImage:(NSData*)para1;

The type in the brackets - (NSData*) is the return type it should be, this is the type of object that you want to return from the method. Then your method name successImage then you would have the parameters :(NSData*)para1 you can add more parameters as well

     - (NSData*)successImage:(NSData*)para1 withAString:(NSString*)para2;

the type inside the brackets of :(NSData*)para1 parameters is the object type it takes.

Hope this helps.