iphone - 获取异常为 "Collection was mutated while being enumerated"

Question

当我使用这段代码时，我得到了 Collection was mutated while being enumerated 异常，任何人都可以建议我如何摆脱这种情况。

PaymentTerms * currentElement;
for (currentElement in termsArray)
{
    printf("\n currentElement Value........%s",[currentElement.days UTF8String]);
    printf("\n Str value...%s",[Str UTF8String]);
    NSRange range = [currentElement.days rangeOfString:Str options:NSCaseInsensitiveSearch];
    if(!(range.location != NSNotFound))
    {
        PaymentTerms *pTerm1 = [[PaymentTerms alloc]init];
        pTerm1.days = Str;
        printf("\n  pTerm1.days...%s",[ pTerm1.days UTF8String]);
        [termsArray addObject:pTerm1];
    }   
}

希望我能从你这边得到快速回复。预先感谢，莫尼什。

Answer 1

在枚举数组时不能更改它。作为解决方法，您应该在临时数组中累积新对象并在枚举后添加它们:

PaymentTerms * currentElement;
NSMutableArray* tempArray = [NSMutableArray array];
for (currentElement in termsArray)
{
    NSRange range = [currentElement.days rangeOfString:Str options:NSCaseInsensitiveSearch];
    if(!(range.location != NSNotFound))
    {
       PaymentTerms *pTerm1 = [[PaymentTerms alloc]init];
       pTerm1.days = Str;
       [tempArray addObject:pTerm1];
       [pTerm1 release];
    }   
}
[termsArray addObjectsFromArray: tempArray];

附言不要忘记释放您创建的 pTerm1 对象 - 您的代码包含内存泄漏

回应发布者的评论(和实际任务)- 我认为最简单的方法是制作 bool 标志，指示是否在循环中找到日值。如果不是 - 在循环结束后添加新对象:

PaymentTerms * currentElement;
BOOL dayFound = NO;
for (currentElement in termsArray)
{
    NSRange range = [currentElement.days rangeOfString:Str options:NSCaseInsensitiveSearch];
    if(range.location != NSNotFound)
        dayFound = YES;
}
if (!dayFound)
     // Create and add new object here