Source Code for Module ButtonLib

  1  # ButtonLib.py 
  2   
  3  import RPi.GPIO as GPIO 
  4  import time 
  5  from threading import Thread 
  6   
  7  DEBUG = False 
  8   
  9  # Button event constants 
 10  BUTTON_PRESSED = 1 
 11  BUTTON_RELEASED = 2 
 12  BUTTON_LONGPRESSED = 3 
 13  BUTTON_CLICKED = 4 
 14  BUTTON_DOUBLECLICKED = 5 
 15  BUTTON_LONGPRESS_DURATION = 2 # default (in s) the button must be pressed to be a long press 
 16  BUTTON_DOUBLECLICK_TIME = 1 # default time (in s) to wait for a double click event 
 17   
 18 -def delay(interval): 
 19      time.sleep(interval / 1000.0) 
 20   
 21 -class ClickThread(Thread): 
 22 -    def __init__(self): 
 23          Thread.__init__(self) 
 24          self.start() 
 25   
 26 -    def run(self): 
 27          if DEBUG: 
 28              print "===>ClickThread started" 
 29          global clickThread 
 30          self.isRunning = True 
 31          startTime = time.time() 
 32          while self.isRunning and (time.time() - startTime < BUTTON_DOUBLECLICK_TIME): 
 33              time.sleep(0.1) 
 34          if clickCount == 1 and not isLongPressEvent: 
 35              if xButtonListener != None: 
 36                  xButtonListener(BUTTON_CLICKED) 
 37              clickThread = None 
 38          self.isRunning  = False 
 39          if DEBUG: 
 40              print "===>ClickThread terminated" 
 41   
 42 -    def stop(self): 
 43          self.isRunning = False 
 44   
 45 -class ButtonThread(Thread): 
 46 -    def __init__(self): 
 47          Thread.__init__(self) 
 48          self.isRunning = False 
 49   
 50 -    def run(self): 
 51          if DEBUG: 
 52              print "===>ButtonThread started" 
 53          self.isRunning = True 
 54          startTime = time.time() 
 55          while self.isRunning and (time.time() - startTime < BUTTON_LONGPRESS_DURATION): 
 56              time.sleep(0.1) 
 57          if self.isRunning: 
 58              if buttonListener != None: 
 59                  buttonListener(BUTTON_LONGPRESSED) 
 60          if DEBUG: 
 61              print "===>ButtonThread terminated" 
 62   
 63 -    def stop(self): 
 64          self.isRunning = False 
 65   
 66 -def onXButtonEvent(event): 
 67      global clickThread, clickCount, isLongPressEvent 
 68      if event == BUTTON_PRESSED: 
 69          if xButtonListener != None: 
 70              xButtonListener(BUTTON_PRESSED) 
 71          isLongPressEvent = False 
 72          if clickThread == None: 
 73              clickCount = 0 
 74              clickThread = ClickThread() 
 75   
 76      elif event == BUTTON_RELEASED: 
 77          if xButtonListener != None: 
 78              xButtonListener(BUTTON_RELEASED) 
 79          if isLongPressEvent and clickThread != None: 
 80              clickThread.stop() 
 81              clickThread = None 
 82              return 
 83          if clickThread != None and clickThread.isRunning: 
 84              clickCount += 1 
 85              if clickCount == 2: 
 86                  clickThread.stop() 
 87                  clickThread = None 
 88                  if xButtonListener != None: 
 89                      xButtonListener(BUTTON_DOUBLECLICKED) 
 90          else: 
 91              clickThread = None 
 92   
 93      elif event == BUTTON_LONGPRESSED: 
 94          isLongPressEvent = True 
 95          if xButtonListener != None: 
 96              xButtonListener(BUTTON_LONGPRESSED) 
 97   
 98  # Hardware callback 
 99 -def onButtonEvent(channel): 
100      global buttonThread, inCallback 
101      if inCallback: # inhibit reentrance 
102          return 
103      inCallback = True 
104      # switch may bounce: down-up-up, down-up-down, down-down-up etc. in fast sequence 
105      if GPIO.input(buttonPin) == GPIO.LOW: 
106          if buttonThread == None: # down-down is suppressed 
107              if DEBUG: 
108                  print "->ButtonDown" 
109              buttonThread = ButtonThread() 
110              buttonThread.start() 
111              if buttonListener != None: 
112                  buttonListener(BUTTON_PRESSED) 
113      else: 
114          if buttonThread != None: # up-up is suppressed 
115              if DEBUG: 
116                  print "->ButtonUp" 
117              buttonThread.stop() 
118              buttonThread.join(200) # wait until finished 
119              buttonThread = None 
120              if buttonListener != None: 
121                  buttonListener(BUTTON_RELEASED) 
122      inCallback = False 
123       
124 -def addXButtonListener(listener): 
125      global xButtonListener 
126      addButtonListener(onXButtonEvent) 
127      xButtonListener = listener 
128   
129 -def addButtonListener(listener): 
130      global buttonListener 
131      buttonListener = listener 
132   
133 -def setButtonPin(pin): 
134      global buttonPin 
135      buttonPin = pin 
136      GPIO.setup(buttonPin, GPIO.IN, GPIO.PUD_UP) 
137      GPIO.add_event_detect(buttonPin, GPIO.BOTH, onButtonEvent) 
138   
139  buttonThread = None 
140  clickThread = None 
141  inCallback = False 
142   
143  # Use physical pin numbers 
144  GPIO.setmode(GPIO.BOARD) 
145  GPIO.setwarnings(False) 
146