ios - <__NSCFDictionary : 0x1557f400> was mutated while being enumerated.'

Question

我有在 iphone 4 上运行的 ios 7 应用程序。我有一个奇怪的问题，由于标题中的错误，应用程序在 for 循环内崩溃。我检查了 SO，它说当您更改要迭代的对象时会发生错误。所以我复制了我用来临时变量的两个变量，但问题仍然存在。第一次迭代完成时出现问题。

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    NSMutableDictionary * badges = [defaults objectForKey:@"badges"];
    NSMutableDictionary *newBadges = badges;
    for(NSString* key in badges)
    {
        NSDictionary* badge = [badges objectForKey:key];
        if([[badge objectForKey:@"achived"]  isEqual: @"NO"])
        {
            if([self checkBadgeCondition:badge])
            {
                NSMutableDictionary *tempBadge = [badge mutableCopy];
                [self showAlertBadge:badge];
                [tempBadge setObject:@"YES" forKey:@"achived"];
                [newBadges setObject:tempBadge forKey:[tempBadge objectForKey:@"name"]];
            }
        }
    }

Answer 1

newBadges = badges

这不是副本，它只是对同一事物的另一种引用。您还应该期望来自用户默认值的字典(或数组)是可变的。所以，在这里制作一个可变副本

newBadges = [badges mutableCopy]