异常＆＃34;发送到不可变对象的变异方法＆＃34;

Question

我在下面的方法中的行[array removeObjectsInArray:toRemove];中有例外，无法理解它的错误..

- (void) handleDearchForTerm:(NSString *)searchTerm
{
    NSMutableArray *sectionsToRemove = [[NSMutableArray alloc] init];
    [self resetSearch];
    for (NSString *key in _keys)
    {
        NSMutableArray *array = [_names valueForKey:key];
        NSMutableArray *toRemove = [[NSMutableArray alloc] init];
        for (NSString *name in array)
        {
            if ([name rangeOfString:searchTerm options:NSCaseInsensitiveSearch].location == NSNotFound)
                [toRemove addObject:name];
        }
        if ([array count] == [toRemove count])
            [sectionsToRemove addObject:key];
        [array removeObjectsInArray:toRemove];
    }
    [_keys removeObjectsInArray:sectionsToRemove];
    [_table reloadData];
}

Answer 1

可能数组只是NSArray的实例，而不是NSMutableArray的实例，您应该检查_names setObject:forKeys:

Answer 2

变化：

 NSMutableArray *array = [_names valueForKey:key];

要：

 NSMutableArray *array = [[NSMutableArray alloc] initWithArray:[_names valueForKey:key]];

或者：

 NSMutableArray *array = [[_names valueForKey:key] mutableCopy];