NSTextStorage的子类导致访问链路崩溃

Question

我正在构建一个自定义NSTextStorage类来查找&匹配自定义用户输入并在我的应用程序中处理它。所以我遵循了几个教程，最值得注意的是objc。创建了一个子类，并将layoutManager设置为与通过nib:

创建的UITextView相同。

-(void)setCustomTextStorage:(NSTextStorage *)customTextStorage
{
    if (_customTextStorage != customTextStorage)
    {
        _customTextStorage = customTextStorage;
        [_customTextStorage addLayoutManager:self.textView.layoutManager];
    }
}

然后为NSTextStorage子类重写processEditing，并在适当的地方添加NSLinkAttributeName。

BTW，样例应用程序在这里可用，确保签出custom-text-storage分支或只是阅读这个问题的差异在这里

现在，当用户点击实际链接时，我得到一个异常，导致应用程序崩溃:

2014-08-20 23:06:45.223 JSQMessages[63170:60b] *** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[NSConcreteTextStorage attribute:atIndex:effectiveRange:]: Range or index out of bounds'
*** First throw call stack:
(
    0   CoreFoundation                      0x00000001025d2495 __exceptionPreprocess + 165
    1   libobjc.A.dylib                     0x00000001021a999e objc_exception_throw + 43
    2   CoreFoundation                      0x00000001025d22ad +[NSException raise:format:] + 205
    3   UIFoundation                        0x000000010558273f -[NSConcreteTextStorage attribute:atIndex:effectiveRange:] + 115
    4   UIKit                               0x00000001013d401b -[UITextView(LinkInteraction) _interactableItemAtPoint:] + 789
    5   UIKit                               0x00000001013d59a4 -[UITextView(LinkInteraction) willInteractWithLinkAtPoint:] + 17
    6   UIKit                               0x000000010108801b -[UITextInteractionAssistant(UITextInteractionAssistant_Internal) gestureRecognizerShouldBegin:] + 305
    7   UIKit                               0x000000010107fc7b -[UIGestureRecognizer _shouldBegin] + 1026
    8   UIKit                               0x000000010107cdfd -[UIGestureRecognizer setState:] + 183
    9   UIKit                               0x0000000100ebcd3f -[UIDelayedAction timerFired:] + 68
    10  Foundation                          0x0000000101d93e14 __NSFireTimer + 83
    11  CoreFoundation                      0x0000000102594c34 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 20
    12  CoreFoundation                      0x00000001025947b2 __CFRunLoopDoTimer + 962
    13  CoreFoundation                      0x000000010257d7be __CFRunLoopRun + 1614
    14  CoreFoundation                      0x000000010257cd83 CFRunLoopRunSpecific + 467
    15  GraphicsServices                    0x0000000103c2ef04 GSEventRunModal + 161
    16  UIKit                               0x0000000100d56e33 UIApplicationMain + 1010
    17  JSQMessages                         0x0000000100014ea3 main + 115
    18  libdyld.dylib                       0x000000010339f5fd start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

这很奇怪，因为我在那里设置了一个断点，backingStore返回一个完全有效的NSDictionary的属性。

谁能帮我解决这个令人抓狂的问题，我很乐意请他喝杯啤酒。

注意:在iOS 8上也可以复制，所以我不认为这是iOS的bug

Answer 1

遇到了同样的问题。我现在找到的唯一解决方案是通过编程方式创建一个完整的堆栈，而不是使用nib:

self.textStorage = [[CustomTextStorage alloc] init];
NSLayoutManager *layoutManager = [[NSLayoutManager alloc] init];
[self.textStorage addLayoutManager:layoutManager];
NSTextContainer *textContainer = [[NSTextContainer alloc] init];
[layoutManager addTextContainer:textContainer];
UITextView *textView = [[UITextView alloc] initWithFrame:frame textContainer:textContainer];
textView.delegate = self;