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我是 OSX Lion 下 Cocoa 编程的新手，所以这是一个我找不到答案的问题。我需要修改用户通过NSTextView. 编辑可能包括替换字符串中的某些部分NSTextStorage以及添加NSTextAttachment对象。我实现了协议并将其NSTextView作为委托提供。我还以以下方式实现了该方法textView:shouldChangeTextInRanges:replacementStrings:：

- (BOOL)textView:(NSTextView *)textView shouldChangeTextInRanges:(NSArray *)affectedRanges replacementStrings:(NSArray *)replacementStrings{
    NSTextStorage* ts=[textView textStorage];
    [ts beginEditing];
    NSMutableString* buf=[ts mutableString];
    //make some completions
    NSRange rng;
    rng.location=0;
    rng.length=[buf length];
    [buf replaceOccurrencesOfString:@"(." withString:@"(0." options:0 range:rng];
    rng.location=0;
    rng.length=[buf length];
    [buf replaceOccurrencesOfString:@"-+" withString:@"-" options:0 range:rng];
    rng.location=0;
    rng.length=[buf length];
    [buf replaceOccurrencesOfString:@"+-" withString:@"-" options:0 range:rng];

    [ts endEditing];
    return YES;
}

因此我尝试了下一个场景：当应用程序启动时，用户在NSTextView一些文本中键入。如果他输入“（。”一切顺利。但是当他输入“-+”（减号、加号、空格）时，该方法崩溃并产生此转储：

[NSConcreteTextStorage attributesAtIndex:effectiveRange:]: Range or index out of bounds
 (
    0   CoreFoundation                      0x00007fff95963286 __exceptionPreprocess + 198
    1   libobjc.A.dylib                     0x00007fff8c32bd5e objc_exception_throw + 43
    2   CoreFoundation                      0x00007fff959630ba +[NSException raise:format:arguments:] + 106
    3   CoreFoundation                      0x00007fff95963044 +[NSException raise:format:] + 116
    4   AppKit                              0x00007fff90acb5bd -[NSConcreteTextStorage attributesAtIndex:effectiveRange:] + 121
    5   AppKit                              0x00007fff90f4cde6 -[NSTextView insertText:replacementRange:] + 840
    6   AppKit                              0x00007fff910fc891 -[NSTextInputContext handleTSMEvent:] + 2289
    7   AppKit                              0x00007fff910fe4fe _NSTSMEventHandler + 165
    8   HIToolbox                           0x00007fff89745308 _ZL23DispatchEventToHandlersP14EventTargetRecP14OpaqueEventRefP14HandlerCallRec + 1263
    9   HIToolbox                           0x00007fff89744914 _ZL30SendEventToEventTargetInternalP14OpaqueEventRefP20OpaqueEventTargetRefP14HandlerCallRec + 446
    10  HIToolbox                           0x00007fff8975b6c7 SendEventToEventTarget + 76
    11  HIToolbox                           0x00007fff89930a4d SendTSMEvent + 35
    12  HIToolbox                           0x00007fff89930dd4 SendUnicodeTextAEToUnicodeDoc + 452
    13  HIToolbox                           0x00007fff8993095e TSMKeyEvent + 629
    14  HIToolbox                           0x00007fff8976f81a TSMProcessRawKeyEvent + 2350
    15  AppKit                              0x00007fff910fbade -[NSTextInputContext handleEvent:] + 639
    16  AppKit                              0x00007fff90fc7eaf -[NSView interpretKeyEvents:] + 248
    17  AppKit                              0x00007fff90f40c65 -[NSTextView keyDown:] + 691
    18  AppKit                              0x00007fff90a20544 -[NSWindow sendEvent:] + 7430
    19  AppKit                              0x00007fff909b868f -[NSApplication sendEvent:] + 5593
    20  AppKit                              0x00007fff9094e682 -[NSApplication run] + 555
    21  AppKit                              0x00007fff90bcd80c NSApplicationMain + 867
    22  myapp                           0x0000000100001302 main + 34
    23  myapp                           0x00000001000012d4 start + 52

似乎缩短的字符串会导致一些越界溢出。

我做错了什么，我该如何解决这个问题？请帮忙。

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1 回答 1

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The -length method returns the quantity of characters in a NSString. The problem is that the first character is in the index 0. Try using [buf length] - 1. This should work.

于 2012-01-22T15:07:54.563 回答