擅长:python、mysql、java
<p>使用布尔值检查矩形是否已创建,如下所示:</p>
<pre><code>rectangleCreated = False
def create(event):
if rectangleCreated:
return
x1, y1 = (event.x - 5), (event.y - 5)
x2, y2 = (event.x + 5), (event.y + 5)
canvas.create_rectangle(x1,y1,x2,y2,fill='red')
rectangleCreated = True
</code></pre>