Tkinter...太空入侵者...敌人移动

Question

我正在用Tkinter开发一个简单的太空入侵者游戏。目前我在想办法让敌人以一定的速度向下移动一整行……当我把move_enemy()里的速度设置为1000毫秒时，游戏就开始卡顿了。非常感谢大家的帮助。

from tkinter import *
# creates window
window = Tk()
size = window.winfo_screenheight()
window.title("This is a window")
# set up geometry using string formatting operator %
window.geometry("%dx%d+%d+%d" % (1000, 1000, 10, 10))
window.update()
# creates canvas
global canvas
canvas = Canvas(window, bg='green')
# pack is a layout manager
canvas.pack(fill=BOTH, expand=1)
canvas.update()
canvas.create_rectangle(0, 1000, 1000, 0, fill="orange", width=10, outline="white",     tag="border")

def shooting():
    global loaded_gun

    c = canvas.coords("player")
    canvas.create_line(c[0],c[1] + 20,c[2],c[3],width=5,fill="yellow",tag="shot")
    loaded_gun = 0


def move_shot(name):
    canvas.after(50)
    canvas.move(name,0,-20)
    canvas.update()

def on_key_press(event):

    global canvas,loaded_gun


    c = canvas.coords("player")

    if event.keysym == 'Left' and c[0] > 0:
        canvas.move("player", -20,0)
    elif event.keysym == 'Right' and c[2] < 1000:
        canvas.move("player", 20, 0)
    elif event.keysym == 'space':
        if loaded_gun == 1:
            shooting()
    elif event.keysym == 'Shift_L':
        loaded_gun = 1
        canvas.delete("shot")

def draw_enemy():
    c = [100,100,170,170]
    inc = 100

    for x in range(0,8):
        for y in range(0,4):
            canvas.create_rectangle(c[0] + inc * x,c[1] + inc * y,c[2] + inc * x,c[3] + inc * y,fill="red",tag="enemy")

def move_enemy():
    canvas.after(1000)
    canvas.move("enemy",0,20)


canvas.create_line(500, 950,500,1000, width=15, fill="red",tag="player")

loaded_gun = 1

draw_enemy()


while True:
    move_shot("shot")
    move_enemy()
    canvas.bind_all('<Key>', on_key_press)


window.mainloop()

Answer 1

Tkinter书籍: Widget的after方法

你也可以不写回调函数。如果不写，这个方法就会等待你指定的毫秒数，而不会处理任何事件（这和使用time.sleep(delay_ms*0.001)是一样的）。

所以 canvas.after(1000)（没有第二个参数）就像 time.sleep(1) 一样，会让整个程序暂停1秒钟（1000毫秒）。

---

编辑:

from tkinter import *
# creates window
window = Tk()
size = window.winfo_screenheight()
window.title("This is a window")
# set up geometry using string formatting operator %
window.geometry("%dx%d+%d+%d" % (1000, 1000, 10, 10))
window.update()
# creates canvas
global canvas
canvas = Canvas(window, bg='green')
# pack is a layout manager
canvas.pack(fill=BOTH, expand=1)
canvas.update()
canvas.create_rectangle(0, 1000, 1000, 0, fill="orange", width=10, outline="white",     tag="border")

def shooting():
    global loaded_gun

    c = canvas.coords("player")
    canvas.create_line(c[0],c[1] + 20,c[2],c[3],width=5,fill="yellow",tag="shot")
    loaded_gun = 0
    move_shot("shot") # furas

def move_shot(name):
    canvas.move(name,0,-20)
    canvas.update()
    window.after(50, move_shot, "shot") # furas

def on_key_press(event):

    global canvas, loaded_gun

    c = canvas.coords("player")

    if event.keysym == 'Left' and c[0] > 0:
        canvas.move("player", -20,0)
    elif event.keysym == 'Right' and c[2] < 1000:
        canvas.move("player", 20, 0)
    elif event.keysym == 'space':
        if loaded_gun == 1:
            shooting()
    elif event.keysym == 'Shift_L':
        loaded_gun = 1
        canvas.delete("shot")

def draw_enemy():
    c = [100,100,170,170]
    inc = 100

    for x in range(0,8):
        for y in range(0,4):
            canvas.create_rectangle(c[0] + inc * x,c[1] + inc * y,c[2] + inc * x,c[3] + inc * y,fill="red",tag="enemy")

def move_enemy():
    canvas.move("enemy",0,20)
    window.after(1000, move_enemy) # furas


canvas.create_line(500, 950,500,1000, width=15, fill="red",tag="player")

loaded_gun = 1

draw_enemy()

window.bind_all('<Key>', on_key_press) # furas

#move_shot() # furas
move_enemy() # furas


window.mainloop()