根据文档,我尝试子类NSTextStorage并在文本视图中使用它：
/* 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; */
所以我尝试使用delegate来处理所有需要的事件,具有相同的功能：
@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
不管我用什么代理：NSTextStorage或NSMutableAttributedString,结果是一样的：
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)’
堆栈跟踪：
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:]
当我打电话时终止开始
[textView insertText:@"123"];
但在标准的NSTextStorage版本中,所有功能都正常工作.
我需要做什么来扩展这个类？
解决方法
除了需要实现的NSAttributedString原始方法之外,我相信还需要调用编辑：range：changeInLength：在replaceCharactersInRange：withString：和setAttributes：range中分别覆盖：
就像是：
- (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];
}
