ios - Objective-C: Method's return value and Completion block, how are they executed? -

I make a photography app in the iPhone and I have these 3 classes: View Controller, CaptureManager, and IMG Processors.

ViewController:

  - (IBAction) takePic: (ID) Sender {images = [CaptureManager Exceed with Multiple Versions: ^ {// Some UI related code .. [IMG Processor Process: Images]; }]; }  

Capture Manager:

  - (NSArray *) LeftModel Images Conclusion: ^ (Zero) Full Handler {// Take Photo Code ... Completed Hondeller (); Return arrayoffimization; }  

So far it serves as desired: imgProcessor processes images taken by captureManager . But I do not know how it works. Back to the array of images I took when the bcos I called Handsler was completed. How was this code executed? Is it a better solution?

Thank you!

You do not need to return the value images as you argue it for cmpletionHandler block can give.

  - Take (zero) with multiple images closing: (zero (^) (NSArray * picture)) completionHnadler {// Take photo code ... completionHnadler (arrayOfImagesTaken); }  

You can call it like this:

  - (IBAction) takePic: (ID) Sender {{CaptureManager Take Various Images End: ^ (NSArray * images) {[IMG processor process: images]; }]; }  

How does this work?

The block here is used as a callback, this code defines the task to execute when a task is completed. When multiple image ending has been concluded, the block will be called fullholder.