问题
According to documentation, I try to subclass NSTextStorage and use it in text view:
/*
NSTextStorage is a semi-abstract subclass of NSMutableAttributedString. It
implements change management (beginEditing/endEditing), verification of
attributes, delegate handling, and layout management notification. The one
aspect it does not implement is the actual attributed string storage --- this is
left up to the subclassers, which need to override the two
NSMutableAttributedString primitives:
- (void)replaceCharactersInRange:(NSRange)range withString:(NSString *)str;
- (void)setAttributes:(NSDictionary *)attrs range:(NSRange)range;
*/
So I try to use delegate, to handle all needed events with same functionality:
@implementation MyTextStorage
- (id) init {
self = [super init];
if (self != nil) {
storage = [[NSMutableAttributedString alloc] init];
}
return self;
}
- (void) dealloc {
[storage release];
[super dealloc];
}
- (NSString *) string {
return [storage string];
}
- (void) replaceCharactersInRange:(NSRange)range withString:(NSString *)str {
[storage replaceCharactersInRange:range withString:str];
}
- (void)setAttributes:(NSDictionary *)attrs range:(NSRange)range {
[storage setAttributes:attrs range:range];
}
@end
It is no matter what I'm use as delegate: NSTextStorage or NSMutableAttributedString, The result is the same:
An uncaught exception was raised * NSRunStorage, _NSBlockNumberForIndex(): index (18446744073709551615) beyond array bounds (0) * Terminating app due to uncaught exception 'NSRangeException', reason: '*** NSRunStorage, _NSBlockNumberForIndex(): index (18446744073709551615) beyond array bounds (0)'
Stack trace:
0 CoreFoundation 0x00007fff840cd7b4 __exceptionPreprocess + 180
1 libobjc.A.dylib 0x00007fff885390f3 objc_exception_throw + 45
2 CoreFoundation 0x00007fff840cd5d7 +[NSException raise:format:arguments:] + 103
3 CoreFoundation 0x00007fff840cd564 +[NSException raise:format:] + 148
4 AppKit 0x00007fff86cc6288 _NSBlockNumberForIndex + 86
5 AppKit 0x00007fff86cc71d5 -[NSLayoutManager textContainerForGlyphAtIndex:effectiveRange:] + 364
6 AppKit 0x00007fff86d1f121 -[NSTextView(NSSharing) didChangeText] + 340
7 AppKit 0x00007fff86d44b68 -[NSTextView insertText:replacementRange:] + 2763
8 CocoaCalculator 0x0000000100002312 -[CalcTextView insertText:] + 65
9 CocoaCalculator 0x00000001000027ac -[CalcTextContainer initWithFrame:] + 1176
10 AppKit 0x00007fff86c23d44 -[NSCustomView nibInstantiate] + 646
11 AppKit 0x00007fff86b7be17 -[NSIBObjectData instantiateObject:] + 259
12 AppKit 0x00007fff86b7b202 -[NSIBObjectData nibInstantiateWithOwner:topLevelObjects:] + 336
13 AppKit 0x00007fff86b7988d loadNib + 226
14 AppKit 0x00007fff86b78d9a +[NSBundle(NSNibLoading) _loadNibFile:nameTable:withZone:ownerBundle:]
Termination start when I try to call
[textView insertText:@"123"];
But in standard NSTextStorage version all works properly.
What I need to do to extend this class ?
回答1:
In addition to the NSAttributedString primitive methods that need implemented, I believe you also need to make a call to edited:range:changeInLength:
inside your overrides of replaceCharactersInRange:withString:
and setAttributes:range:
respectively.
Something like:
- (void) replaceCharactersInRange:(NSRange)range withString:(NSString *)str {
[storage replaceCharactersInRange:range withString:str];
[self edited:NSTextStorageEditedCharacters range:range changeInLength:[str length] - range.length];
}
- (void)setAttributes:(NSDictionary *)attrs range:(NSRange)range {
[storage setAttributes:attrs range:range];
[self edited:NSTextStorageEditedAttributes range:range changeInLength:0];
}
回答2:
The NSTextStorage
documentation is a little bit vague in this area. The comment you quote in your question, about only needing to override 2 of the NSMutableAttributedString
primitives only means that you don't have to override the other NSMutableAttributedString
primitives.
You still have to override the primitives for the NSAttributedString
superclass. Which means you need to implement -attributesAtIndex:effectiveRange:
, -length
and -string
. I notice you did include an implementation of -string
, so the two remaining ought to do it.
If you add:
- (NSUInteger)length
{
return [storage length];
}
- (NSDictionary *)attributesAtIndex:(NSUInteger)location effectiveRange:(NSRangePointer)range
{
return [storage attributesAtIndex:location effectiveRange:range];
}
... then hopefully it will fix this problem.
来源:https://stackoverflow.com/questions/5960550/how-to-extend-nstextstorage