This example shows how you can increase or decrease the number in a number box each time the up or down arrow keys are pressed. The incdec object is made to be connected to the integer number box in the manner shown here. The messages inc and dec to incdec will increment and decrement the attached number box.
This example show 2 ways to increase and decrease a value on a number box. One uses a set of trigger, textbutton, int, and + objects, the other simply uses the incdec object.
The incdec object is a user interface object with an up arrow and a down arrow. It stores a number, and it also has an internal step size (increment attribute), which is 1 by default. When you click on the up or down arrow, incdec will increase or decrease its internal value by the increment, and send out the number.
The up-down arrow keys seem like reasonable keys to use for incrementing or decrementing a number box or a slider. But rather than require a new key press for each step up or down, you can use a fast metro to trigger messages continuously as long as the key is pressed. There are several ways one could implement this in Max; here's one example.