我如何从WxHaskell面板中移除小部件 [英] How can I remove widgets from WxHaskell panel

问题描述

我的google-fu让我失望了。我如何删除已添加到 Panel（）的小部件？例如，在下面，我希望控件 - 面板再次变空。

My google-fu has failed me. How can I remove widgets that I've added to a Panel () ? For example, in the following, I want the controls-panel to become empty again.

buildGUI = do
  f <- frame [ text := "Hello" ]

  controls <- panel f []
  ctext <- staticText controls [ text := "Foo" ]
  set controls [ layout := margin 5 (widget ctext) ]

  set f [ layout := widget controls ]
  {- delete ctext ? How? -}
  return ()

（我试图构建一个动态GUI，当它更新时，我需要摆脱旧的控件）。

(I'm trying to build a dynamic GUI, and I need to get rid of the old controls when it updates).

推荐答案

您可以使其不可见并将其从布局。这实际上并没有将其删除，但会动态更改用户界面：

You could make it not visible and remove it from the layout. This doesn't actually remove it but does change the UI dynamically:

import Graphics.UI.WX

buildGUI = do
  f <- frame [ text := "Hello" ]

  controls <- panel f []
  ctext <- staticText controls [ text := "Foo" ]
  butn <- button controls [text := "Remove the Foo"]        -- I've added a button to remove Foo
  set controls [ layout := row 0 [margin 5 (widget ctext),
                                  margin 5 (widget butn) ]]

  set f [ layout := widget controls ]

  set butn [on command := do
      set ctext [visible := False]                          -- so ctext doesn't show
      set controls [layout := margin 5 (widget butn) ]]     -- so ctext doesn't take up space
  return ()

main = start buildGUI

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