How do I resolve this? TypeError: main.<locals>.<lambda>() missing 1 required positional-CodePudding

I'm using tkinter to make 2048 game gui, I created this function control_game I want to have it such that anytime I click these keys (up, down, left, right) on my keyboard the control_game function should be called from my main function. But anytime I run the code and press any of those keys this error is displayed: TypeError: main.<locals>.<lambda>() missing 1 required positional argument: 'gamepanel'

I have read about binding from this link

Main function

def main(gamepanel):
    won = False
    lost = False

    get_random(gamepanel)
    get_random(gamepanel)
    gamepanel.update_board()

    while not (won or lost):
        
        gamepanel.root.bind_all("<Key>", lambda event, gamepanel: control_game(event, gamepanel))
        gamepanel.root.focus_set()

        gamepanel.root.mainloop()

Control game function

def control_game(event, gamepanel):

    
    key_pressed = event.keysym

    if key_pressed == "Up": # Up
        transpose(gamepanel)
        compress(gamepanel)
        merge(gamepanel)
        compress(gamepanel)
        transpose(gamepanel)
    elif key_pressed == "Down": #Down
        transpose(gamepanel)
        reverse(gamepanel)
        compress(gamepanel)
        merge(gamepanel)
        compress(gamepanel)
        reverse(gamepanel)
        transpose(gamepanel)
    elif key_pressed == "Left": #Left
        compress(gamepanel)
        merge(gamepanel)
        compress(gamepanel)
    elif key_pressed == "Right": # Right
        reverse(gamepanel)
        compress(gamepanel)
        merge(gamepanel)
        compress(gamepanel)
        reverse(gamepanel)

This my board class:

class Board(Frame):
    def __init__(self):
        self.FOREGROUND_COLOR = {
            2: "#776e65",
            4: "#776e65",
            8: "#f9f6f2",
            16: "#f9f6f2",
            32: "#f9f6f2",
            64: "#f9f6f2",
            128: "#f9f6f2",
            256: "#f9f6f2",
            512: "#f9f6f2",
            1024: "#f9f6f2",
            2048: "#f9f6f2",
            4096: "#776e65",
            8192: "#f9f6f2",
            16384: "#776e65",
            32768: "#776e65",
            65536: "#f9f6f2",
        }

        self.BACKGROUND_COLOR = {
            2: "#eee4da",
            4: "#ede0c8",
            8: "#f2b179",
            16: "#f59563",
            32: "#f67c5f",
            64: "#f65e3b",
            128: "#edcf72",
            256: "#edcc61",
            512: "#edc850",
            1024: "#edc53f",
            2048: "#edc22e",
            4096: "#eee4da",
            8192: "#edc22e",
            16384: "#f2b179",
            32768: "#f59563",
            65536: "#f67c5f",
        }
        self.boardSize = 4

        self.moved = False
        self.merged = False
        self.compressed = False
        self.gameMatrix = []
        self.gameTile = [self.boardSize * [0] for _ in range(self.boardSize)]
        self.score = 0

        self.root = Tk()
        self.root.title("2048 by denstream-io")
   
        self.windowStyle = ttk.Style()
        self.windowStyle.configure(
            "Grid.TFrame",
            background="#92877D",  # BBADAO
            boderwidth=5,
            relief="raised",
            width="500p",
            height="500p",
        )

        self.cellStyle = ttk.Style()
        self.cellStyle.configure(
            "Cell.TFrame",
            # background="yellow",#EEE4DA
            boderwidth=5,
        )

        self.labelStyle = ttk.Style()
        self.labelStyle.configure(
            "Label.TLabel",
            anchor="center",
        )

        self.gameWindow = ttk.Frame(self.root, style="Grid.TFrame")
        self.gameWindow.grid(sticky=(N, W, E, S))

        for i in range(int(self.boardSize)):
            labeled_row = []
            for j in range(int(self.boardSize)):
                self.gameCell = ttk.Frame(
                    self.gameWindow, relief="raised", style="Cell.TFrame"
                )
                self.gameCell.grid(column=i, row=j, sticky=(N, W, E, S))
                self.eachLabel = ttk.Label(
                    self.gameWindow, text="", style="Label.TLabel"
                )
                self.eachLabel.grid(column=i, row=j, sticky=(N, W, E, S))
                labeled_row.append(self.eachLabel)
            self.gameMatrix.append(labeled_row)


        for child in self.gameWindow.winfo_children():
            child.grid_configure(padx=5, pady=5, ipadx="25p", ipady="25p")

    def update_board(self):

        for i in range(self.boardSize):
            for j in range(self.boardSize):
                if self.gameTile[i][j] == 0:
                    self.gameMatrix[i][j].configure(
                        text="", background="#9E948A"
                    ) 
                else:
                    self.gameMatrix[i][j].configure(
                        text=str(self.gameTile[i][j]),
                        background=self.BACKGROUND_COLOR[self.gameTile[i][j]],
                        foreground=self.FOREGROUND_COLOR[self.gameTile[i][j]],
                    )

Entire Traceback:

Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Users\dennis-lc\AppData\Local\Programs\Python\Python310\lib\tkinter\__init__.py", line 1921, in __call__
    return self.func(*args)
TypeError: main.<locals>.<lambda>() missing 1 required positional argument: 'gamepanel'

Anytime I exit the game frame, this error is displayed:

Traceback (most recent call last):
  File "C:\Users\dennis-lc\Desktop\denstream-io\games\2048\2048\project.py", line 363, in <module>
    main(gamepanel)
  File "C:\Users\dennis-lc\Desktop\denstream-io\games\2048\2048\project.py", line 143, in main
    gamepanel.root.bind_all("<Key>", lambda event, gamepanel: control_game(event, gamepanel))
  File "C:\Users\dennis-lc\AppData\Local\Programs\Python\Python310\lib\tkinter\__init__.py", line 1435, in bind_all
    return self._bind(('bind', 'all'), sequence, func, add, 0)
  File "C:\Users\dennis-lc\AppData\Local\Programs\Python\Python310\lib\tkinter\__init__.py", line 1375, in _bind
    self.tk.call(what   (sequence, cmd))
_tkinter.TclError: can't invoke "bind" command: application has been destroyed

My code at the end of the file:

if __name__ == '__main__':
    gamepanel = Board()
    main(gamepanel)

CodePudding user response：

When an event callback is triggered, tkinter passes one positional argument containing information about the event.

This is your lambda definition:

lambda event, gamepanel: control_game(event, gamepanel))

It is roughly equivalent to this:

def something(event, gamepanel):
    control_game(event, gamepanel)

Notice how it requires two parmeters: event and gamepanel. Since tkinter only passes a single parameter, you get the error missing 1 required positional argument: 'gamepanel' which accurately describes the problem.

The solution is to convert the positional argument to a keyword argument with a default value:

lambda event, gamepanel=gamepanel: control_game(event, gamepanel))
#                      ^^^^^^^^^^

Tkinter will pass a single positional parameter, event, and the other argument will be given the default value.

The error can't invoke "bind" command: application has been destroyed is again accurately describing the problem. Consider this code:

while not (won or lost):
    
    gamepanel.root.bind_all("<Key>", lambda event, gamepanel: control_game(event, gamepanel))
    gamepanel.root.focus_set()

    gamepanel.root.mainloop()

When the window is destroyed, gamepanel.root.mainloop() will exit. When it exits, the while loop will go to a second iteration. In that iteration you're trying to do a binding on the window that was just destroyed. Hence, can't invoke "bind" command: application has been destroyed.

The solution is to remove the loop. There is almost never a reason to call mainloop in a loop. If you feel you need to, then you need to make sure that each iteration recreates the window.