1. Express gratitude: If you have helped this friend before, such as answering some questions or providing some help, he may want to express his gratitude in this way.

2. Enhance friendship: This friend may want to establish a better relationship with you and enhance friendship in this way.

3. Pursuit of goodwill: If this friend has a goodwill towards you, he may want to win your goodwill in this way.

4. What do you want from you? This friend may want to win your trust in this way and then ask you for some help or advice.

In either case, if you don't want to accept takeout, you can politely refuse, for example, to show that you have already eaten or that you don't like it very much. If you want to accept this takeaway, you can make an appointment with this friend and enjoy the food.