如何通过双击使NSTextView余额定界符? [英] How to make NSTextView balance delimiters with a double-click?
问题描述
通常有一个文本编辑器来处理代码或其他结构化内容，以平衡某种定界符.当您双击{时，它会选择匹配的}，或者类似地用于()对，[]对等.如何在Cocoa/Obj-C的NSTextView中实现此行为?
It's common to have a text editor for code or other structured content that balances delimiters of some sort; when you double click on a { it selects to the matching }, or similarly for ( ) pairs, [ ] pairs, etc. How can I implement this behavior in NSTextView in Cocoa/Obj-C?
(我将暂时发布一个答案，因为我对此一无所获，并花费了今天实施解决方案.欢迎提供更好的答案.)
(I will be posting an answer momentarily, since I found nothing on SO about this and spent today implementing a solution. Better answers are welcome.)
附录:
这与此问题不同.有关NSTextField的信息，主要涉及NSTextField和字段编辑器的问题. 如果通过将自定义NSTextView子类替换为字段编辑器来解决该问题，那么该自定义子类当然可以使用此处提供的解决方案；但是可能还有许多其他方法可以解决NSTextField的问题，并且将自定义NSTextView子类替换为字段编辑器显然不是解决该问题的正确方法，无论如何，程序员在NSTextView(这可能是更常见的问题)可能不太关心所有这些NSTextField和字段编辑器问题.因此，这是一个不同的问题–尽管我将添加该问题的链接到该问题，以作为可能的方向.
This is not the same as this question, which is about NSTextField and is primarily concerned with NSTextField and field editor issues. If that question is solved by substituting a custom NSTextView subclass into the field editor, then that custom subclass could use the solution given here, of course; but there might be many other ways to solve the problem for NSTextField, and substituting a custom NSTextView subclass into the field editor is not obviously the right solution to that problem, and in any case a programmer concerned with delimiter balancing in NSTextView (which is presumably the more common problem) could care less about all of those NSTextField and field editor issues. So that is a different question – although I will add a link from that question to this one, as one possible direction it could go.
这也与此问题不同，双击时在NSTextView中单词"的定义.根据 Apple的文档 ，这些是采用不同解决方案的不同问题；对于定界符平衡(此问题)，Apple特别建议使用NSTextView的selectionRangeForProposedRange:granularity:方法，而对于更改单词的定义(该问题)，Apple特别声明selectionRangeForProposedRange:granularity:方法不应 .
This is also not the same as this question, which is really about changing the definition of a "word" in NSTextView when a double-click occurs. As per Apple's documentation, these are different problems with different solutions; for delimiter-balancing (this question) Apple specifically recommends the use of NSTextView's selectionRangeForProposedRange:granularity: method, whereas for changing the definition of a word (that question) Apple specifically states that the selectionRangeForProposedRange:granularity: method should not be used.
推荐答案
In their Cocoa Text Architecture Guide (https://developer.apple.com/library/prerelease/mac/documentation/TextFonts/Conceptual/CocoaTextArchitecture/TextEditing/TextEditing.html), Apple suggests subclassing NSTextView and overriding selectionRangeForProposedRange:granularity: to achieve this sort of thing; they even say "For example, in a code editor you can provide a delegate that extends a double click on a brace or parenthesis character to its matching delimiter." However, it is not immediately clear how to achieve this, since you want the delimiter match to happen only at after a simple double-click on a delimiter, not after a double-click-drag or even a double-click-hold-release.
我能想到的最好的解决方案包括覆盖mouseDown:，并做一些关于事务状态的记账工作.也许有一种更简单的方法.我省略了实际上计算分隔符匹配的代码的核心部分.这取决于您要匹配的分隔符，可能存在的语法复杂性(字符串，注释)等等.在我的代码中，我实际上调用了一个令牌生成器来获取令牌流，然后使用它来查找匹配的定界符. YMMV.所以，这就是我所拥有的:
The best solution I could come up with involves overriding mouseDown: as well, and doing a little bookkeeping about the state of affairs. Maybe there is a simpler way. I've left out the core part of the code where the delimiter match actually gets calculated; that will depend on what delimiters you're matching, what syntactical complexities (strings, comments) might exist, and so forth. In my code I actually call a tokenizer to get a token stream, and I use that to find the matching delimiter. YMMV. So, here's what I've got:
在您的NSTextView子类界面(或更好的类扩展)中:
In your NSTextView subclass interface (or class extension, better yet):
// these are used in selectionRangeForProposedRange:granularity:
// to balance delimiters properly
BOOL inEligibleDoubleClick;
NSTimeInterval doubleDownTime;
在您的NSTextView子类实现中:
- (void)mouseDown:(NSEvent *)theEvent
{
// Start out willing to work with a double-click for delimiter-balancing;
// see selectionRangeForProposedRange:proposedCharRange granularity: below
inEligibleDoubleClick = YES;
[super mouseDown:theEvent];
}
- (NSRange)selectionRangeForProposedRange:(NSRange)proposedCharRange
granularity:(NSSelectionGranularity)granularity
{
if ((granularity == NSSelectByWord) && inEligibleDoubleClick)
{
// The proposed range has to be zero-length to qualify
if (proposedCharRange.length == 0)
{
NSEvent *event = [NSApp currentEvent];
NSEventType eventType = [event type];
NSTimeInterval eventTime = [event timestamp];
if (eventType == NSLeftMouseDown)
{
// This is the mouseDown of the double-click; we do not want
// to modify the selection here, just log the time
doubleDownTime = eventTime;
}
else if (eventType == NSLeftMouseUp)
{
// After the double-click interval since the second mouseDown,
// the mouseUp is no longer eligible
if (eventTime - doubleDownTime <= [NSEvent doubleClickInterval])
{
NSString *scriptString = [[self textStorage] string];
...insert delimiter-finding code here...
...return the matched range, or NSBeep()...
}
else
{
inEligibleDoubleClick = false;
}
}
else
{
inEligibleDoubleClick = false;
}
}
else
{
inEligibleDoubleClick = false;
}
}
return [super selectionRangeForProposedRange:proposedCharRange
granularity:granularity];
}
这有点脆弱，因为它依赖于NSTextView的跟踪以特定的方式工作并以特定的方式调用selectionRangeForProposedRange:granularity:，但是假设并不大.我认为它非常健壮.
It's a little fragile, because it relies on NSTextView's tracking working in a particular way and calling out to selectionRangeForProposedRange:granularity: in a particular way, but the assumptions are not large; I imagine it's pretty robust.
这篇关于如何通过双击使NSTextView余额定界符?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
