This question is NOT a duplicate of this question: Why doesn't the .bind() method work with a frame widget in Tkinter?
As you can see, I set the focus to the current frame in my game_frame() method.
I'm writing a Chip-8 emulator in Python and using Tkinter for my GUI. The emulator is running, but I can't get Tkinter to recognize keypresses. Here is my code:
def game_frame(self):
self.screen = Frame(self.emulator_frame, width=640, height=320)
self.screen.focus_set()
self.canvas = Canvas(self.screen, width=640, height=320, bg="black")
self._root.bind("<KeyPress-A>", self.hello)
for key in self.CPU.KEY_MAP.keys():
print(key)
self.screen.bind(key, self.hello)
self.screen.pack()
self.canvas.pack()
def hello(self, event):
if event.keysym in self.CPU.KEY_MAP.keys():
self.CPU.keypad[self.CPU.KEY_MAP[event.keysym]] = 1
self.CPU.key_pressed = True
self.CPU.pc += 2
sys.exit()
def run_game(self, event):
self.game_frame()
self.CPU.load_rom("TANK")
while True:
self._root.update()
self.after(0, self.CPU.emulate_cycle)
Could you please help me figure out what's going wrong? I think it might have something to do with my game loop interfering with the key bindings, but I'm not sure. The hello method never gets called when I run the game because the program continues to run in an infinite loop and never exits, regardless of what key is pressed. Thank you!
The problem could be due to two things. Without seeing all your code it's impossible to say for sure.
For one, you are binding to a capital "A" rather than a lowercase "a" -- have you testing that the binding works or not when you press a capital A?
Also, you are using after and update incorrectly. You may be starving the event loop, preventing it from processing key presses. The right way to run a function periodically is to have a function that (re)schedules itself.
class CPU_Class():
...
def run_cycle(self):
self.emulate_cycle()
self._root.after(1, self.run_cycle)
Two things to note:
don't use after(0, ...) -- you need to give tkinter at least a ms or so to process other events.
the run_cycle function is responsible for running one cycle, and then scheduling the next cycle to run in the future.
Once you do that, you no longer need your while loop. You can simply call run_cycle once, and that will start the CPU running.
Related
I have decided to finally work on a project, as I've tried to code in python before, with at least some success. In my project, I am trying to build a menu that lets me "Auto-farm" in a game. It uses 3 modules, namely pynput, pause, and PySimpleGUI.
Whenever I run the code, it runs fine, until I click the button that starts the automation part. It runs completely fine, but I have to force close the GUI prompt that shows up as it just completely stops responding to input until you close it.
How I can make a stop button, and stop my program from freezing up?
I am using 2 files to keep this project slightly more organized, although I don't know if this is the best way to go around doing this. These 2 files are main.py and chand.py.
main.py
import PySimpleGUI as sg
import chand
loop = 0
layout = [[sg.Text("Welcome to RedGrowie's autofarm menu!")], [sg.Button("Chandeliers")]]
window = sg.Window("Autofarming Menu", layout)
while True:
event, values = window.read()
if event == sg.WIN_CLOSED:
break
if event == "Chandeliers":
loop = 1
if loop == 1:
chand.Chandeliers.start(self=chand.Chandeliers)
window.close
chand.py
from pynput.keyboard import Key, Controller
import pause
keyboard = Controller()
start = "0"
class Chandeliers:
def d_press(self):
keyboard.press("d")
pause.milliseconds(70)
keyboard.release("d")
pause.milliseconds(300)
keyboard.release(Key.space)
def space_press(self):
keyboard.press(Key.space)
pause.milliseconds(1)
#keyboard.release(Key.space)
def start(self):
start = "1"
while start == "1":
self.d_press(self)
self.space_press(self)
Your Chandeliers.start function loops indefinitely, so the call from the main loop in main.py never gets returned to. If you want both loops to be running at the same time, you probably need to use threading or some other means of concurrency. Or you might be able to interleave the two loops somehow, depending on the timing requirements for each one.
As a side note, you are using your Chandeliers class in a very odd way. You're never creating an instance of the class, but rather calling the methods it defines as if they were class methods (but with manual passing of the class, in the misleadingly named self argument.
You should probably not do that. Either treat the class as a normal one, and create an instance:
cha = chand.Chandeliers()
chat.start() # and change start to not manually pass self any more
Or you should do away with the unneeded class all together and just make the methods into top-level functions.
I have a python code that includes tkinter window and other running tasks.
I've been trying to bind "WM_DELETE_WINDOW" event to a function that exits my python code when I close the window but can't achieve that.
This is what I try:
def on_exit():
root.destroy()
sys.exit()
root.protocol('WM_DELETE_WINDOW', on_exit)
The window is destroyed successfully but the python code doesn't exit. Any possible reason for sys.exit() not to work?
What am I doing wrong? any alternative approach should I try?
Doing some testing I figured out what can be the problem.
Here's a small code that summarizes my code which is much bigger.
import tkinter as tk
import sys
root = tk.Tk()
submitted = tk.IntVar()
def on_exit():
root.destroy()
sys.exit()
root.protocol('WM_DELETE_WINDOW', on_exit)
def submit():
submitted.set(1)
print("submitted")
button= tk.Button(root, text="Submit",command=submit)
button.pack()
button.wait_variable(submitted)
root.mainloop()
I believe now that wait_variable is the source of the problem.
And the code actually exits when I added submitted.set(1) to on_exit() ( or if I clicked the button first before closing the window ) but if I tried closing the window without pressing the button, the code won't exit.
So does this mean that wait_variable not only makes tkinter app wait, but also prevents python code exiting?!
I tried os._exit(1) and it worked, but I think it's not clean.
As your updated question points out the problem is wait_variable(). Going off the documentation for this method wait_variable() enters a local event loop that wont interrupt the mainloop however it appears that until that local event loop is terminated (the variable is updated in some way) it will prevent the python instance from terminating as there is still an active loop. So in order to prevent this you have also correctly pointed out you need to update this variable right before you terminate the tk instance.
This might seam odd but it is the behavior I would expect. It is my understanding that an active loop needs to be terminated before a python instance can exit.
As Bryan has pointed out in the comments the wait_variable() method is "a function which calls the vwait command inside the embedded tcl interpreter. This tcl interpreter knows nothing about python exceptions which is likely why it doesn't recognize the python exception raised by sys.exit()"
Link to relevant documentation:
wait_variable()
Relevant text from link:
wait_variable(name)
Waits for the given Tkinter variable to
change. This method enters a local event loop, so other parts of the
application will still be responsive. The local event loop is
terminated when the variable is updated (setting it to it’s current
value also counts).
You can also set the variable to whatever it is currently set as to terminate this event loop.
This line should work for you:
submitted.set(submitted.get())
That said you do not actually need sys.exit(). You can simply use root.destroy().
You new function should look like this:
def on_exit():
submitted.set(submitted.get())
root.destroy()
The python instance will automatically close if there is no more code after the mainloop.
I started coding snake in python 3. As GUI i use Tkinter.
I got a timer which waits for a second an then calls the method again. Well now my question is how to i stop the self.wait?
I know i could work around this pretty easily, but i had this problem already somewhere else, so it would be nice to know how i can stop this.
This is the method which moves the snake around. (Only the timer is critical). The timer is here so it moves every second.
def move_snake(self):
self.after(1000, self.move_snake)
# code goes on
Now if i change the direction (by pressing a button) i do following:
def change_direction(self, event):
self.pressed = event.keysym
self.move_snake()
If i do this this way the "old" timer still is active and therefore the method gets called multiple times (it adds an additional timer when you press an button).
It would be nice that just the latest timer is activated.
Do you need more information?
Assuming that move_snake uses self.pressed, you don't need to call move_snake inside of change_direction.
However, if you really want to stop the old loop and start a new loop, you can save the id that is returned from after and give that to after_cancel:
def move_snake(self):
self.after_id = self.after(1000, self.move_snake)
# code goes on
def change_direction(self, event):
self.pressed = event.keysym
# cancel the old loop
self.after_cancel(self.after_id)
# start a new loop
self.move_snake()
I've searched for a simple animation code with Tkinter but I've found very different examples and I can't understand the correct way to write an animation.
Here my working code to display a simple moving circle:
import tkinter as tk
import time
root=tk.Tk()
canvas=tk.Canvas(root,width=400,height=400)
canvas.pack()
circle=canvas.create_oval(50,50,80,80,outline="white",fill="blue")
def redraw():
canvas.after(100,redraw)
canvas.move(circle,5,5)
canvas.update()
canvas.after(100,redraw)
root.mainloop()
In this code I can't correctly understand: how the after method works, where correctly put the update and the move method (before after method ?), is there another way to write an animation code? may you post me another example and comment the code please?
Thanks :)
Calling update
You should not call canvas.update(). As a general rule of thumb you should never call update. For a short essay on why, see this essay written by one of the original developers of the underlying tcl interpreter.
If you take out the call to canvas.update(), you have the proper way to do animation in a tkinter program.
Calling after to start the animation
You don't need to call after immediately before calling root.mainloop(). This works just as well:
...
redraw()
root.mainloop()
The choice to use or not use after in this specific case is dependent on if you want the animation to start immediately (possibly even before the widget is visible) or if you want it to happen after a short delay (possibly after the widget is made visible)
How after works
mainloop is nothing more than an infinite loop that checks the event queue for events. When it finds an event, it pops it off of the list and processes it. after is nothing more than making a request that says "in 100 ms, please add a new event to the queue". When the time limit expires, an event is added to the queue that says, in effect, "run this command". The next time the loop checks for events, it sees this event, pulls it off of the queue, and runs the command.
When you call after from within a method that itself was called by after, you're saying in effect "wait 100ms and do it again", creating an infinite loop. If you put the call to after before moving the object, you're saying "every 100ms run this function". If you put it after you're saying "run this function 100 ms after the last time it was run". The difference is very subtle and usually not perceptible unless your function takes a long time to run.
my code is:
from tkinter import *
import time
tk = Tk()
płótno = Canvas(tk, width=500, height=500)
płótno.pack()
płótno.create_polygon(10,10,10,70,70,10,fill="blue",outline="black")
for x in range(0,51):
płótno.move(1,5,0)
płótno.update()
rest(0.05)
płótno means canvas
I'm trying to learn how to use the thread module. I followed along with the instructions here: http://effbot.org/zone/tkinter-threads.htm
My hope is the test script will:
Print out the "count" every two seconds
Show a pop-up dialog window (also every 2 seconds)
The pop-ups should be allowed to accumulate (if I don't click "OK" for a while, there should be
multiple pop-ups)
However, when I run this script it will freeze the main window and after a while crash. I think I'm not implementing the thread module correctly.
Could someone please have a look and point out what I'm doing wrong?
Here is what I've tried so far:
from Tkinter import *
import thread
import Queue
import time
class TestApp:
def __init__(self, parent):
self.super_Parent = parent
self.main_container = Frame(parent)
self.main_container.pack()
self.top_frame = Frame(self.main_container)
self.top_frame.pack(side=TOP)
self.bottom_frame = Frame(self.main_container)
self.bottom_frame.pack(side=TOP)
self.text_box = Text(self.top_frame)
self.text_box.config(height=20, width=20)
self.text_box.pack()
self.queue = Queue.Queue()
self.update_me()
def show_popup(self):
self.my_popup = Toplevel(self.main_container)
self.my_popup.geometry('100x100')
self.popup_label = Label(self.my_popup, text="Hello!")
self.popup_label.pack(side=TOP)
self.pop_button = Button(self.my_popup, text="OK", command=self.my_popup.destroy)
self.pop_button.pack(side=TOP)
def write(self, line):
self.queue.put(line)
def update_me(self):
try:
while 1:
line = self.queue.get_nowait()
if line is None:
self.text_box.delete(1.0, END)
else:
self.text_box.insert(END, str(line))
self.text_box.see(END)
self.text_box.update_idletasks()
except Queue.Empty:
pass
self.text_box.after(100, self.update_me)
def pipeToWidget(input, widget):
widget.write(input)
def start_thread():
thread.start_new(start_test, (widget,))
def start_test(widget):
count = 0
while True:
pipeToWidget(str(count) + "\n", widget)
count += 1
time.sleep(2)
widget.show_popup()
root = Tk()
widget = TestApp(root)
start_button = Button(widget.bottom_frame, command=start_thread)
start_button.configure(text="Start Test")
start_button.pack(side=LEFT)
root.title("Testing Thread Module")
root.mainloop()
I can't reproduce your problem, but I can see why it would happen.
You're using the queue to pass messages from the background thread to the main thread for updating text_box, which is correct. But you're also calling widget.show_popup() from the background thread, which means it creates and displays a new Toplevel in the background thread. That's not correct.
All UI code must run in the same thread—not all UI code for each top-level window, all UI code period. On some platforms, you may get away with running each window in its own thread (or even free-threading everything), but that isn't supposed to work, and definitely will crash or do improper things on some platforms. (Also, that single UI thread has to be the initial thread on some platforms, but that isn't relevant here.)
So, to fix this, you need to do the same dance for creating the popups that you do for updating the textbox.
The obvious way to do that is to move the widget.show_popup() to the loop in update_me(). If you want it to happen 2 seconds after the textbox updates, just add self.top_frame.after(2000, self.show_popup) to the method.
But I'm guessing you're trying to teach yourself how to have multiple independent updating mechanisms, so telling you "just use a single update queue for everything" may not be a good answer. In that case, just create two queues, and a separate update method servicing each queue. Then, do your pipeToWidget, sleep 2 seconds, then pipeToPopup.
Another way around this is to use mtTkinter. It basically does exactly what you're doing, but makes it automatic, pushing each actual Tk GUI call onto a queue to be run later by the main loop. Of course your objects themselves have to be thread-safe, and this also means that you have to deal with the GUI calls from one thread getting interleaved with calls from another thread. But as long as neither of those is a problem (and they don't seem to be in your case), it's like magic.
If you want to know why this is freezing and/or crashing for you on Win7 and not for me on OS X 10.8… well, you really need to look into a mess of Tcl, C, and Python code, and also at how each thing is built. And, unless it's something simple (like your Tk build isn't free-threaded), it wouldn't tell you much anyway. The code isn't supposed to work, and if it seems to work for me… that probably just means it would work every time until the most important demo of my career, at which point it would fail.