NSMutableArray设置值，使用时注意问题

NSArray *selected_data = [dataManager dataForKey:HOME_DATA_KEY_SELECTED_DECORATES withDomain:HOME_DATA_DOMN_DECORATES];

NSLog(@"DragableDecorate: saveNewPosition, selected_data=%@", selected_data);

NSMutableArray * mutableArray = [[NSMutableArray alloc] initWithCapacity:[selected_data count]];

NSMutableDictionary * mDict;

//要用另一个可变的数组接收一下
for(NSDictionary *dict in selected_data)
{
mDict = [dict mutableCopy];
NSString *d_id = [dict objectForKey:HOME_DATA_KEY_SELECTED_DECORATES_ID];
if ([d_id compare:self.uuid]==NSOrderedSame) {
NSString *posi = [NSString stringWithFormat:@"{%f,%f}",self.position.x,self.position.y];
[mDict setObject:@"ss" forKey:@"dd"];
[mDict setObject:posi forKey:CONFIG_META_POSITION_TAG];

//            break;
}
[mutableArray addObject:mDict];
}

[dataManager saveData:mutableArray forKey:HOME_DATA_KEY_DARGABLE_DECORATES withDomain:HOME_DATA_DOMN_DECORATES];

[mutableArray release];