objective-c – 如何扩展NSTextStorage？

发布时间：2020-12-16 06:02:27 所属栏目：百科来源：网络整理

导读：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 la

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];
}

（编辑：李大同）

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