Pyglet步行動畫。錯誤：'無類型'對象沒有'繪製'屬性

Question

此代碼在黑色背景上顯示圖像assassin1.png。這個想法是，只要我按下<right-direction>鍵，角色就會移動並使用assassin2.png和assassin3.png顯示動畫。我已經能夠移動角色併成功顯示動畫，而不是同時顯示動畫。

下面的代碼，只要我不按<right direction>鍵運行：一旦

import pyglet 

def sprite_type(type_ = "standing"): 
    if type_ == "moving-forward": 
     moving_forward_image_list = [pyglet.image.load('assassin2.png'), pyglet.image.load('assassin3.png')] 
     moving_forward_animation = pyglet.image.Animation.from_image_sequence(moving_forward_image_list, 0.3) 
     return moving_forward_animation 
    if type_ == "standing": 
     standing_animation = pyglet.image.load("assassin1.png") 
     return standing_animation 

class Assassin(pyglet.sprite.Sprite): 
    def __init__(self, batch, img): 
     pyglet.sprite.Sprite.__init__(self, img, x = 50, y = 30) 

    def stand(self, batch, img): 
     self.batch = batch 
     self.img = img 

    def move(self, batch, img): 
     self.batch = batch 
     self.img = img  

class Game(pyglet.window.Window): 
    def __init__(self): 
     pyglet.window.Window.__init__(self, width = 315, height = 220) 
     self.batch_draw = pyglet.graphics.Batch() 
     self.player = Assassin(batch = self.batch_draw, img = sprite_type()) 
     self.fps_display = pyglet.clock.ClockDisplay() 
     self.keys_held = []  
     self.schedule = pyglet.clock.schedule_interval(func = self.update, interval = 1/60.) 

    def on_draw(self): 
     self.clear()   
     self.fps_display.draw() 
     self.batch_draw.draw() 
     self.player.draw() 

    def on_key_press(self, symbol, modifiers): 
     self.keys_held.append(symbol) 
     if symbol == pyglet.window.key.RIGHT: 
      self.player = self.player.move(batch = self.batch_draw, img = sprite_type("moving-forward")) 
      print "The 'RIGHT' key was pressed" 

    def on_key_release(self, symbol, modifiers): 
     self.keys_held.pop(self.keys_held.index(symbol)) 
     self.player = self.player.stand(batch = self.batch_draw, img = sprite_type("standing")) 

    def update(self, interval): 
     if pyglet.window.key.RIGHT in self.keys_held: 
      self.player.x += 50 * interval 

if __name__ == "__main__": 
    window = Game() 
    pyglet.app.run() 

我按<right-direction>鍵會出現以下錯誤：

Traceback (most recent call last): 
    File "ircex.py", line 55, in <module> 
    pyglet.app.run() 
    File "/usr/local/lib/python2.7/dist-packages/pyglet/app/__init__.py", line 264, in run 
    EventLoop().run() 
    File "/usr/local/lib/python2.7/dist-packages/pyglet/app/xlib.py", line 93, in run 
    sleep_time = self.idle() 
    File "/usr/local/lib/python2.7/dist-packages/pyglet/app/__init__.py", line 193, in idle 
    window.dispatch_event('on_draw') 
    File "/usr/local/lib/python2.7/dist-packages/pyglet/window/__init__.py", line 1219, in dispatch_event 
    EventDispatcher.dispatch_event(self, *args) 
    File "/usr/local/lib/python2.7/dist-packages/pyglet/event.py", line 349, in dispatch_event 
    return getattr(self, event_type)(*args) 
    File "pyglet-walk.py", line 37, in on_draw 
    self.player.draw() 
AttributeError: 'NoneType' object has no attribute 'draw' 

Answer 1

在您的代碼move()方法返回None：

class Assassin(pyglet.sprite.Sprite): 
    (...) 


    def move(self, batch, img): 
     self.batch = batch 
     self.img = img  

然後在該線下方設置self.player返回的player.move()價值，這是None：

self.player = self.player.move(batch = self.batch_draw, img = sprite_type("moving-forward")) 

導致AttributeError: 'NoneType' object has no attribute 'draw'，因爲self.player爲None，並試圖調用draw()就可以了。