Many superiors take it for granted that their direct reports are always available for their issues and don’t consider that their calls or sudden visits might interrupt someone else. If such behavior is typical for your boss, you can try to change it actively by talking to him and proposing a regular meeting or briefing.
1) Talk to your boss
Your boss might not be aware of how much he is disturbing you. The first step is to tell him in an appropriate manner that you wish to structure the way you interact in a different way. Please check my article on how to criticize other people. You can also tell him that he is disturbing himself too each time he come to you. If you had a regular meeting it would not only save your time but also his time.
2) Ask for a regular meeting
Ask your boss for a regular meeting. Depending on how closely you work together a weekly meeting or daily briefing is appropriate. This meetings purpose is to quickly exchange information on what is coming up, receive tasks from your boss and return deliverables from previous meetings. This meeting ideally takes place early in the morning, so that there are less surprises for the rest of the day.
3) Carry something to work on with you
If you regularly are called to your boss or to a meeting and often have to wait outside until it is your turn, take something to work on with you. You can convert this waiting time into productive time. It also makes a good impression and improves your image in the company.
Of course there always will be some sudden and urgent matters coming up. Depending on what kind of business your company is in you will have to cope with a certain amount of interruptions from your boss. However, the above mentioned items should help you to significantly reduce such interruptions. If there is no change in the behavior of your boss you might have to consider changing position or company.