I am trying to create a program, that simply reads 2 pins in this case pin 17 and pin 27 using the BCM setmode. Depending inthe value of each pin ( 0 or 1 ) the program will show on a screen a different image.
My problem is, the first time i run the program the image it shows is the correct one, but if meanwhile i set any pin a different state (ON/OFF), the program don't upload the right image on the screen, showing me a error message.
If i just try to run "prints", it works fine, but with images i have always this problem. I never pass right after the first image. Being stuck with the initial image all program long. I get an error in create_image return self._create.
EDIT:Error message image in the link below
error i get https://i.sstatic.net/q6qgp.png
import Tkinter as tk
import RPi.GPIO as GPIO
import time
GPIO.setmode(GPIO.BCM)
GPIO.setup(17,GPIO.IN)
GPIO.setup(27,GPIO.IN)
app = tk.Tk()
app.attributes("-fullscreen", True)
app.title('Presence State')
screen_width = app.winfo_screenwidth()
screen_height = app.winfo_screenheight()
emptyP = tk.PhotoImage(file = "./images/emptyPresence.jpg")
leftP = tk.PhotoImage(file = "./images/leftPresence.jpg")
rightP = tk.PhotoImage(file = "./images/rightPresence.jpg")
bothP = tk.PhotoImage(file = "./images/bothSidesPresence.jpg")
fname = tk.Canvas(app, bg = "black" , width = screen_width, height =
screen_height)
def empty():
image = fname.create_image(screen_width/2, screen_height/2, anchor =
tk.CENTER, image = emptyP)
def left():
image = fname.create_image(screen_width/2, screen_height/2, anchor =
tk.CENTER, image = leftP)
def right():
image = fname.create_image(screen_width/2, screen_height/2, anchor =
tk.CENTER, image = rightP)
def both():
image = fname.create_image(screen_width/2, screen_height/2, anchor =
tk.CENTER, image = bothP)
while(1):
if GPIO.input(17) == 0 and GPIO.input(27) == 0:
empty()
time.sleep(.5)
elif GPIO.input(17) == 1 and GPIO.input(27) == 0:
left()
time.sleep(.5)
elif GPIO.input(17) == 0 and GPIO.input(27) == 1:
right()
time.sleep(.5)
else:
both()
time.sleep(.5)
fname.pack()
app.mainloop()
I don't have a RaspberryPi so I've created two Checkbuttons to simulate the IO pins. I've shown the result in a Label. Amending the result to show images shouldn't be too difficult. The function on_after calls itself every 500 milliseconds in place of the original sleep(0.5)s
import tkinter as tk
from tkinter import ttk
root = tk.Tk()
root.geometry('400x100')
root.title('"After" Demonstation')
# Set up fake GPIO Pins as Checkbuttons
# IntVars to easily read the state.
gpio17 = tk.IntVar()
gpio27 = tk.IntVar()
# Initialise to zero
gpio17.set(0)
gpio27.set(0)
ttk.Checkbutton(root, variable = gpio17, text = 'GPIO 17', width = 20).grid( row = 0, column = 0)
ttk.Checkbutton(root, variable = gpio27, text = 'GPIO 27', width = 20).grid( row = 0, column = 2)
# I'm using a label for simplicity. Amendments required
# below to cope with images.
result = tk.StringVar()
ttk.Label(root, textvariable = result, width = 20 ).grid(row=1, column=1)
DELAY = 500 # in milliseconds
def on_after():
""" Reads the state of the io pins and sets the result
to the appropriate value. """
# Code to fetch the IO states will be different with real pins.
io17 = gpio17.get() # Get the button states
io27 = gpio27.get()
# Set the result. Will be different with images.
if io17:
if io27:
result.set('Both')
else:
result.set('Left')
else:
if io27:
result.set('Right')
else:
result.set('None')
id = root.after( DELAY, on_after) # This implements the loop by calling on_after again.
id = root.after( 1, on_after) # Start the loop.
root.mainloop()