Objective c doubleValue上的选择器无效

对Objective-C有点陌生，所以请容忍我

首先，我使用FMDB库进行SQLite管理

我正在使用以下方法填充NSMutableDictionary：

//....
while([effectivenessResults next]) //this loops through the results of a query (verified that this works)
    {
        NSMutableArray *dFactors = [[NSMutableArray alloc]init];
        if([resultDict objectForKey:[effectivenessResults stringForColumn:@"tName"]])
        {
            dFactors = [resultDict objectForKey:[effectivenessResults stringForColumn:@"tName"]];
        }
        NSNumber *effectivenessValToAdd = [NSNumber numberWithDouble:[effectivenessResults doubleForColumn:@"dFactor"]/100];
        [dFactors addObject:[NSMutableString stringWithFormat:@"%@",effectivenessValToAdd]];
        [resultDict setObject:dFactors forKey:[effectivenessResults stringForColumn:@"tName"]];
    }

for(id type in tEffect) //tEffect is the NSMutableDictionary, returned from the previous code (there known as resultDict)
{
    effectivenessString = [self getEffectivenessString:[tEffect objectForKey:type]];

    tInfo = [NSMutableString stringWithFormat:@"%@", [tInfo stringByAppendingFormat:@"%@: %@\n", type, effectivenessString]];

}

我正在正确返回数组（我已经验证了这一点）。然后，我在别处使用以下方法访问此NSMutableDictionary：

//....
while([effectivenessResults next]) //this loops through the results of a query (verified that this works)
    {
        NSMutableArray *dFactors = [[NSMutableArray alloc]init];
        if([resultDict objectForKey:[effectivenessResults stringForColumn:@"tName"]])
        {
            dFactors = [resultDict objectForKey:[effectivenessResults stringForColumn:@"tName"]];
        }
        NSNumber *effectivenessValToAdd = [NSNumber numberWithDouble:[effectivenessResults doubleForColumn:@"dFactor"]/100];
        [dFactors addObject:[NSMutableString stringWithFormat:@"%@",effectivenessValToAdd]];
        [resultDict setObject:dFactors forKey:[effectivenessResults stringForColumn:@"tName"]];
    }

for(id type in tEffect) //tEffect is the NSMutableDictionary, returned from the previous code (there known as resultDict)
{
    effectivenessString = [self getEffectivenessString:[tEffect objectForKey:type]];

    tInfo = [NSMutableString stringWithFormat:@"%@", [tInfo stringByAppendingFormat:@"%@: %@\n", type, effectivenessString]];

}

它调用以下两种方法：

-(NSMutableString *)getEffectivenessString:(NSNumber *) numberPassedIn
{
    double dFactor = [numberPassedIn doubleValue];
    //adds the above value to a string, this will not affect anything
}

及

重要注意事项：此错误发生在检索时，而不是在填充NSMutableDictionary时。这意味着这本词典的数量不是问题，但可能与检索数据时遇到问题有关

---

那么是什么导致了这个错误呢？

您的代码很难理解。以后请发布一个编译过的最小样本，或者至少是一个可理解的代码块

话虽如此，我相信你的问题在于这一点：

for(id type in tEffect) //tEffect is the NSMutableDictionary, returned from the previous code (there known as resultDict)
{
    effectivenessString = [self getEffectivenessString:[tEffect objectForKey:type]];

resultdct

包含什么

[resultDict setObject:dFactors ...

但是

dfacts

是一个

NSMutableArray

。Well

getEffectivenessString

需要一个

NSNumber

，而不是

NSMutableArray

。它抱怨道。此外，我认为您打算让该方法采用字符串，而不是数字，尽管我不明白为什么在加载它们时（而不是在使用它们时）不进行强制转换

---

由于Objective C不支持强类型数组或字典，因此将来最好的防御方法是更合理地命名变量。当你试图调用一个需要一个带数组的数字的方法时，它应该很突出。

我好像忘记调用我在问题中提供的

listProduct

方法了。这是一个非常愚蠢的疏忽。另外，为了提供一个易于阅读的问题，我试图缩短代码，但这可能会使您更难理解。非常感谢。