2. Class = object factory¶

2.1. Class SoundPanel¶

from browser import document, html

class SoundPanel:
   def __init__(self, sound_file):
     self.sound_file = sound_file  # Add this line
     self.track = html.AUDIO(src=sound_file)
     self.track_playing = False
     self.volume = 1.0

def track_toggle(self, ev):
      if self.track_playing:
         self.track.pause()
         print("Stopping:", self.sound_file)
      else:
         self.track.play()
         print("Playing:", self.sound_file)
      self.track_playing = not self.track_playing

def change_volume(self, ev):
      self.volume = float(ev.target.value)
      self.track.volume = self.volume
      print("Volume changed to:", self.volume)

app_div = html.DIV(id='app')

sound_panel = SoundPanel('https://bigsoundbank.com/UPLOAD/mp3/0751.mp3')

track_button = html.INPUT(type='checkbox')
track_button.bind('change', sound_panel.track_toggle)

track_label = html.LABEL('Play Sound')
track_label <= track_button

volume_slider = html.INPUT(type='range', min='0', max='1', step='0.1')
volume_slider.bind('input', sound_panel.change_volume)

volume_label = html.LABEL('Volume')
volume_label <= volume_slider

app_div <= sound_panel.track
app_div <= track_label
app_div <= volume_label

document <= app_div

2.2. Main program¶

Try running this code in your PC and see the code dynamically generate soundpanels for wav files in your directory.

from tkinter import *
from sound_panel import *
import pygame.mixer
import os

app = Tk()
app.title("Head First Mix")

mixer = pygame.mixer
mixer.init()

dirList = os.listdir(".")
for fname in dirList:
   if fname.endswith(".wav") and fname[0] in '345':
      SoundPanel(app,mixer,fname).pack()

def shutdown():
   mixer.stop()
   app.destroy()

app.protocol("WM_DELETE_WINDOW",shutdown)
app.mainloop()

Congratulations! Now you know how to create complex programs with little code.

2.3. Remember¶

Classes are object factories
Class = methods + data
Create objects = instantiate a class
class - begins the definition of a class
self - assigned to the current object
__init__() - called when the object is created