How to get Control back from NSOperationQueue
<p>Can you please tell me How can I get Control back from NSOperationQueue</p>

<p>Following is my real question which I asked earlier:</p>

<p>Hi friends , I made an app which plays the song on clicking on the image of artist.(see image attached). Each artist image is implemented on button and on clicking this button, a function is being called which first downloads and then plays the song. I passed this method(function) in a thread but problem is that every time when I click on the image of artist(button) new threads starts running and then multiple songs gets started playing concurrently. How can I use "NSOperation and NSOperationQueue" so that only one song will run at a time . Please help.</p>

<p><img src="http://i.stack.imgur.com/suCLn.png" alt="alt text">
Thanks in advance</p>

<p>Now I am able to play song by adding them in queue but when songs starts playing i m not able to do anything on my Screen until song is finished or I scroll the table. </p>
