Python / Tkinter-识别点击对象 [英] Python/Tkinter - Identify object on click

问题描述

我正在尝试创建一个程序，将单击时的对象颜色从白色更改为黑色，或者将单击之前的颜色从白色更改为黑色。我希望程序仅在对象是矩形时才更改颜色。我该如何实现呢？

I am trying to create a program that changes the object colour on click from white to black or from white to black depending of the previous colour. I would want the program change the colour only if the object is a rectangle. How can I make the this happen?

这是我的代码：

import tkinter as tk

root = tk.Tk()

cv = tk.Canvas(root, height=800, width=800)
cv.pack()

def onclick(event):
    item = cv.find_closest(event.x, event.y)

    current_color = cv.itemcget(item, 'fill')

    if current_color == 'black':
        cv.itemconfig(item, fill='white')

    else:
        cv.itemconfig(item, fill='black')


cv.bind('<Button-1>', onclick)

cv.create_line(50, 50, 60, 60, width=2)

cv. create_rectangle(80, 80, 100, 100)

root.mainloop()

在此代码中，程序将更改任何对象的填充颜色。我希望它仅对矩形进行更改。

In this code the program changes the fill colour for any object. I would want it to change it only for rectangles.

感谢帮助。

推荐答案

以下是此问题的三种常见解决方案：

Here are three common solutions to this problem:

您可以向画布询问对象的类型：

You can ask the canvas for the type of the object:

item_type = cv.type(item)
if item_type == "rectangle":
    # this item is a rectangle
else:
    # this item is NOT a rectangle

使用标签

另一种解决方案是给每个项目一个或多个标签。然后，您可以查询当前项目的标签。

Using tags

Another solution is to give each item one or more tags. You can then query the tags for the current item.

首先，在要点击的项目上包含一个或多个标签：

First, include one or more tags on the items you want to be clickable:

cv. create_rectangle(80, 80, 100, 100, tags=("clickable",))

下一步，检查您感兴趣的商品上的标签，并查看您的标签是否在该商品的标签集中：

Next, check for the tags on the item you're curious about, and check to see if your tag is in the set of tags for that item:

tags = cv.itemcget(item, "tags")
if "clickable" in tags:
    # this item has the "clickable" tag
else:
    # this item does NOT have the "clickable" tag

在标签上创建绑定

第三个选择是将绑定附加到标签，而不是整个画布。执行此操作时，仅在单击带有给定标签的项目时才调用函数，从而无需进行任何运行时检查：

Create bindings on tags

A third option is to attach the bindings to the tags rather than the canvas as a whole. When you do this, your function will only be called when you click on item with the given tag, eliminating the need to do any sort of runtime check:

cv.tag_bind("clickable", "<1>", onclick)

这篇关于Python / Tkinter-识别点击对象的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！