I would start with a meeting with the student and his family, to find out: a) What his interests are and b) What his IEP goals are. It is important to implement a curriculum that will best meet the student's needs, and he is likely behaving this way because he dislikes, or has not interest in the current curriculum.

I would look to take into account the students goal on his IEP and use this goals as a guiding factor to determine what exactly you should be focusing on within the curriculum during instruction. I would use his interest in working with computers or the I-pad as a positive reward for him completing the required work during instruction.

Let him earn the reward of working on the computer or I-pad. Tell him that when he works for a certain amount of time off the computer, then he can earn a certain amount of time on the computer. Use a timer so that he understands that his time is up when the timer goes off. Work with him to see what strategies you could use that are meaningful off the computer. For example, find out if he really likes to do science experiments or really likes to read, and incorporate those in his work.

I would be sure to not use the computers and iPads as a negative reinforcement. Taking away time from the technology should not be an answer. Some teachers would probably just assume say "Then you can not go on the computers at all" and they should not be used as a punishment. But perhaps more time when he completes the other tasks, etc.

The teacher can connect the I Pad lessons to different classwork. If he enjoys a character on the I Pad, have the character present on other work. Also, wean him into other classwork slowly and with a timer. Start with 5 minutes and build up to longer sessions to keep disruptions limited.

Start making your lessons available to him online, such as power points or worksheets can be done online.

Allowing the student to complete his work only at the computer station or on the iPad is not only unfair to the rest of the class who have to complete some of their work away from the computers, but is also unfair to John in the long run. Students need to have experience competing work using multiple sources. Developing skills with other sources will prepare them for future education setting as well as the real world. I would sit down with John and tell him that he cannot complete all of his work using these technological items. I would remind him that using the computer and iPad are privileges, and that if he continues to not complete his work he will not be allowed to use these items at all. Using the iPad and computer as a reward system may help get John back on track.