objective-c - Put the obtained pictures in an array and use a for loop to call the single picture upload interface to upload the pictures. Why is only the last picture uploaded successfully?

Question

Answer 1

First of all, I don’t know OC very well. I don’t know whether your method of uploading pictures is single-threaded or multi-threaded. However, I feel that it should not be executed in a For loop. Putting it in a For loop will upload all pictures. You can consider it. Add an upload success event listener. After each picture is uploaded successfully or fails, the next picture is uploaded.

Answer 2

I still don’t understand why