在 scala.swing 中，如何从容器中删除组件？

发布于 2024-11-04 04:08:27 字数 415 浏览 0 评论 0原文

在 scala.swing 中，我可以像这样向容器添加组件：

new Frame {
  contents += label
}

但有时我想清除容器的内容并用新组件替换它们。根据文档，我应该能够执行以下操作：

frame.contents.remove(0)

或者

frame.contents.clear

但是这些都不能编译（“清除/删除不是 Seq[scala.swing.Component] 的成员”）。

我该如何解决这个问题？另外，初始化后我似乎无法调用 frame.contents += blah 。如果是这样，如何将新组件添加到容器中？

原文

In scala.swing, I can add a component to a container like so:

new Frame {
  contents += label
}

but sometimes I'd like to clear the contents of a container and replace them with new components. Based on the docs, I should be able to do:

frame.contents.remove(0)

frame.contents.clear

but neither of those compile ("clear/remove is not a member of Seq[scala.swing.Component]").

How can I resolve this? Also, it seems that I can't call frame.contents += blah after intialization. If this is so, how do I add a new component to a Container?

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飘然心甜 2024-11-11 04:08:27

如果您具体讨论的是Frame，则只能添加一项，因此使用该方法

def contents_= (c: Component) : Unit

应该会很好。在 REPL 中尝试一下（一次一行，这样您就可以看到发生了什么）：

import scala.swing._
val f = new Frame { contents = new Label("Hi") }
f.visible = true
f.contents = new Label("Hey there")

如果您使用的东西旨在包含多个项目，例如 BoxPanel、contents< /code> 是一个 Buffer，因此您可以向其中添加或从中删除：

val bp = new BoxPanel(Orientation.Vertical)
val (label1,label2) = (new Label("Hi"), new Label("there"))
bp.contents += label1
bp.contents += label2
f.contents = bp    // Now you see "Hi" "there" stacked
bp.contents -= label1
f.pack             // "Hi" disappears--need pack not repaint to fix layout
bp.contents += label1
f.pack             // "Hi" is back, but at the end

如果您有其他东西，例如要扩展的 Component，那么您的工作就是使用缓冲区覆盖 contents 或使用其他方式修改它（或如 J-16 所说从 SequentialContainer 继承）。

If you're talking about Frame specifically, you can only add one item, so use the method

def contents_= (c: Component) : Unit

and you should be good. Try this out in the REPL (one line at a time so you can see what's going on):

import scala.swing._
val f = new Frame { contents = new Label("Hi") }
f.visible = true
f.contents = new Label("Hey there")

If you're using something that is intended to have multiple items like a BoxPanel, contents is a Buffer so you can add to it and remove from it:

val bp = new BoxPanel(Orientation.Vertical)
val (label1,label2) = (new Label("Hi"), new Label("there"))
bp.contents += label1
bp.contents += label2
f.contents = bp    // Now you see "Hi" "there" stacked
bp.contents -= label1
f.pack             // "Hi" disappears--need pack not repaint to fix layout
bp.contents += label1
f.pack             // "Hi" is back, but at the end

If you have something else like a Component that you're extending, it is your job to override contents with a buffer or have some other way of modifying it (or inherit from SequentialContainer as J-16 said).

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