使JTextArea的部分不可编辑（不是整个JTextArea！） [英] Make parts of a JTextArea non editable (not the whole JTextArea!)

问题描述

我目前正在使用Swing的控制台窗口。它基于JTextArea，就像一个常见的命令行。在一行中键入命令，然后按Enter键。在下一行中，显示输出，在该输出下，您可以编写下一个命令。

I'm currently working on a console window in Swing. It's based on a JTextArea and works like a common command line. You type a command in one line and press enter. In the next line, the output is shown and under that output, you could write the next command.

现在我想，您只能编辑当前行命令。上面的所有行（旧命令和结果）都应该是不可编辑的。我该怎么做？

Now I want, that you could only edit the current line with your command. All lines above (old commands and results) should be non editable. How can I do this?

推荐答案

您不需要创建自己的组件。

You do not need to create your own component.

这可以使用自定义 DocumentFilter 。

您可以从 textPane.getDocument（）获取文档并通过 document.setFilter（）在其上设置过滤器。在过滤器中，您可以检查提示位置，并且只有在位置在提示之后才允许修改。

You can get the document from textPane.getDocument() and set a filter on it by document.setFilter(). Within the filter, you can check the prompt position, and only allow modifications if the position is after the prompt.

例如：

private class Filter extends DocumentFilter {
    public void insertString(final FilterBypass fb, final int offset, final String string, final AttributeSet attr)
            throws BadLocationException {
        if (offset >= promptPosition) {
            super.insertString(fb, offset, string, attr);
        }
    }

    public void remove(final FilterBypass fb, final int offset, final int length) throws BadLocationException {
        if (offset >= promptPosition) {
            super.remove(fb, offset, length);
        }
    }

    public void replace(final FilterBypass fb, final int offset, final int length, final String text, final AttributeSet attrs)
            throws BadLocationException {
        if (offset >= promptPosition) {
            super.replace(fb, offset, length, text, attrs);
        }
    }
}

然而，这会阻止你以编程方式将内容插入终端的输出（不可编辑）部分。您可以做的是在您要添加输出时设置的过滤器上的直通标记，或者（我做了什么）在附加输出之前将文档过滤器设置为null，然后在您输出时重置它完成。

However, this prevents you from programmatically inserting content into the output (noneditable) section of the terminal. What you can do instead is either a passthrough flag on your filter that you set when you're about to add the output, or (what I did) set the document filter to null before appending the output, and then reset it when you're done.

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