Page 396 -

custom widgets and classes

Test Drive

With the code typed into IDLE, take this latest version of the DJ’s program
for a quick spin by pressing F5.

These check buttons
start and stop each
of the tracks.

These scales control
the volume.

The program has created a checkbox and a volume slider for each track.
The program called the create_gui() function twice, creating two sets
of widgets. Of course, you can call it as many times as you like and the
create_gui() function will create the two widgets for each track.
When you click on the two checkboxes, the two tracks both play at the
same time! You can start and stop each of them independently by selecting
and deselecting the checkboxes. But more than that, the volume sliders
independently change the volume of the tracks, allowing you to mix them
together.
This is a big deal. The create_gui() function is not only creating the
separate widgets and adding them to the interface, but it is also creating the
event handlers that allow each pair of widgets to control each separate track.
Here the program is controlling just two tracks, but if you added more calls
to create_gui() in the code, there’s no reason why you couldn’t get the
interface to work with as many tracks as you like.

Let’s see what the DJ thinks.

you are here 4 361