如何在 R 中访问和修改 Tcl/Tk 对象的同级对象 [英] How to access and modify a sibling of a Tcl/Tk object in R

问题描述

简而言之:

我在 R 中使用 tcltk 包.但非 R 用户也可能会提出想法并提供 R 以外的其他语言的示例.我在 R 中有一个 Tcl/Tk 对象列表..1.1.1.1 .1.1.1.2 .1.1.1.3 并且想分别访问和修改每个对象.我该怎么做?

I use tcltk package in R. But non-R users may suggest ideas too and provide examples in other language than R. I have a list of Tcl/Tk objects in R <Tcl> .1.1.1.1 .1.1.1.2 .1.1.1.3 and want to access and modify each object separately. How can I do it?

或者如果我有按钮 A 对象，我如何访问和修改按钮 B 对象?

Or If I have button A object, how can I access and modify button B object?

详情:

我有以下小部件:

创建它的代码:

library(tcltk)

top <- tktoplevel()

frame_1 <- tkframe(top)
tkgrid(frame_1)

frame_n <- tkframe(frame_1)
tkgrid(frame_n)

b1 <- ttkbutton(frame_n,  text = "button A")
b2 <- ttkbutton(frame_n,  text = "button B")
b3 <- ttkbutton(frame_n,  text = "button c")
tkgrid(b1, b2, b3)

假设我只能访问 b1:

class(b1)
# [1] "tkwin"

我想访问和修改 b1 的兄弟，就好像我有对象 b2 等(例如):

I want to access and modify the siblings of b1 as if I had objects b2, etc. (for example):

tkcget(b2, "-text")             # Get text
tkconfigure(b2, text = "New B") # Change text

通过使用 tkwinfo，我设法访问了 b1 的父级并获得了兄弟姐妹列表(我不确定从技术上讲它是否是一个列表")，但我不知道，如何一一访问/修改它们:

By using tkwinfo, I managed to access the parent of b1 and get a list of siblings (I'm not sure if technically it is a "list"), but I don't know, how to access/modify each of them one by one:

(parent_of_b1 <- tkwinfo("parent", b1))
# <Tcl> .1.1.1 

(siblings_of_b1 <- tkwinfo("children", parent_of_b1))
# <Tcl> .1.1.1.1 .1.1.1.2 .1.1.1.3 

class(siblings_of_b1)
# "tclObj"

我的尝试导致错误:

tkcget(siblings_of_b1, "-text")
# Error in structure(.External(.C_dotTclObjv, objv), class = "tclObj") : 
#   [tcl] invalid command name ".1.1.1.1 .1.1.1.2 .1.1.1.3".

很可能我不知道对对象进行子集化的方法.我该怎么做?

Most probably I don't know the way to subset the object. How can I do it?

更新:根据@Donal Fellows 的评论，我找到了解决方案.

UPDATE: based on the comments of @Donal Fellows, I found the solution.

函数 as.character() 完成这项工作.

Function as.character() does the job.

(my_tcl_object <- tkwinfo("children", parent_of_b1))
# <Tcl> .1.1.1.1 .1.1.1.2 .1.1.1.3 

as.character(my_tcl_object)
## [1] ".1.1.1.1" ".1.1.1.2" ".1.1.1.3"

在这种情况下，tclvalue() + strsplit() 同样有效:

In this situation, tclvalue() + strsplit() works as well:

strsplit(tclvalue(my_tcl_object), " ", fixed = TRUE)[[1]]
## [1] ".1.1.1.1" ".1.1.1.2" ".1.1.1.3"

但是，一般来说(对于其他问题)，as.character() vs. tclvalue() + strsplit() 可能会给出不同的结果.

But, in general (for other problems), as.character() vs. tclvalue() + strsplit() may give different results.

推荐答案

问题在于 winfo children 子命令(使用底层 Tcl 名称)返回一个 Tcl 小部件标识符列表.一般来说，从其他语言处理这有点麻烦(因为处理引用规则的潜在问题)但因为生成的小部件标识符只包含 ASCII 数字和 . 字符和分隔符只是单个空格，只需按空格分割会给你正确的东西.

The issue is that the winfo children subcommand (using the underlying Tcl name) returns a Tcl list of widget identifiers. In general, this is a bit messy to deal with from other languages (because of potential issues with handling quoting rules) but because the generated widget identifiers just contain ASCII digits and . characters and the separators are just single spaces, simply splitting by space will give you the right thing.

(siblings_of_b1 <- strsplit(tkwinfo("children", parent_of_b1), " ", fixed = TRUE))

当然，您需要遍历结果列表.多个兄弟姐妹是多个兄弟姐妹.(另外，不要忘记这 包括 b1 本身；你没有要求实际的兄弟姐妹，而是父母的孩子.)

You'll need to iterate over the resulting list, of course. Multiple siblings are multiple siblings. (Also, don't forget that this includes b1 itself; you've not asked for the actual siblings, but rather the children of the parent.)

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