如何删除 Canvas 文本对象? [英] How do you delete a Canvas text object?

问题描述

例如，这是一个 create_text:

This is for example a create_text:

self.__canvas.create_text(350, lineVotes, text=str(likesPrinted),
                          font=("calibri", 30), fill="#66FF99", anchor=E)

我怎么能用按钮删除它?

How could I delete this with a button?

推荐答案

一种方法是使用 对象 ID 所有 Canvas 对象构造函数返回:>

One way to do it is by using the object ID that all Canvas object constructors return:

self.text_id = self.__canvas.create_text(350, lineVotes,
                                         text=str(likesPrinted),
                                         font=("calibri", 30),
                                         fill="#66FF99", anchor=E)

然后你可以使用 Canvas 对象的 delete() 方法如下:

Then afterwards you can use the Canvas object's delete() method like this:

self.__canvas.delete(self.text_id)

另一种方法是附加一个 tag 到 Canvas 对象，并使用它:

Another way is to attach a tag to the Canvas object, and use that:

self.__canvas.create_text(350, lineVotes,
                          text=str(likesPrinted),
                          font=("calibri", 30), fill="#66FF99", anchor=E,
                          tag="some_tag")

然后将标记传递给 delete() 方法而不是对象 ID:

And then pass the tag to the delete() method instead of the object ID:

self.__canvas.delete("some_tag")

标签的名称可以是任何不包含空格或句点的字符串.

The name of a tag can be any string that does not contain white space or periods.

标签更强大，因为您可以为多个对象提供相同的标签，然后作为一个组对它们进行操作.相反，一个对象可以通过指定一个元组来附加多个标签:即 tag=("1234", "@special", "posn:13,42") 在构造函数调用中.

Tags are more powerful because you can give the same one to multiple objects and then act on them as a group. Conversely, an object can have more than one tag attached to it by specifying a tuple of them: i.e. tag=("1234", "@special", "posn:13,42") in the constructor call.

要在单击 Button 时发生这种情况，您还需要定义一个函数或方法，当它被点击时调用上述 Canvas 方法之一.叫.然后，在创建按钮小部件时，通过 command= 配置选项指定其名称.

To make this happen when a Button is clicked, you would need to also define a function or method that makes a call to one of the above Canvas methods when it's called. Then, when creating the button widget, specify its name via the command= configuration option.

例如(在 class 定义中):

For example (within a class definition):

class Class:
    ...

    def create_widgets(self):
        self.text_id = self.__canvas.create_text(350, lineVotes, text=str(likesPrinted),
                                                 font=("calibri", 30), fill="#66FF99", 
                                                 anchor=E)
        self.delete_btn = Button(root, text="Delete text", command=self.delete_text)
        self.delete_btn.pack()
    
    def delete_text(self):
        """ Delete the canvas text object. """
        if self.text_id:
            self.__canvas.delete(self.text_id)
            self.text_id = None  # To avoid multiple deletions.

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