如何从“(void)”中获取 NSString 值方法转换成“(BOOL)” Objective-C 中的方法？

Question

我想将“city”的值获取到“CurrentLocation”中。

- (void)reverseGeocoder:(MKPlacemark *)placemark {
    NSString *city = [myPlacemark.addressDictionary objectForKey:(NSString*) kABPersonAddressCityKey];
}

- (BOOL)fetchAndParseRSS {        
    NSString *currentLocation; // I want 'city' here.
    return YES;
}

Answer 1

为什么您的反向地理编码器消息返回无效？我会这样写：

- (NSString*)reverseGeocoder:(Placemark*)myPlacemark
{
    // assuming myPlacemark is holding a reference to the dictionary (so no need to retain)
    NSString *city = [myPlacemark.addressDictionary objectForKey:kABPersonAddressCityKey];
    return city;
}

-(BOOL)fetchAndParseRss
{
    // you need to get myPlacemark from somewhere, presumably from the geocode request?
    Placemark * myPlacemark = [self getPlacemark];

    NSString * CurrentLocation = [self reverseGeocoder:myPlacemark];
}

在这段代码中，我假设 Placemark 是一个类，其中一个 addressDictionary NSDictionary 定义为属性。

如果您确实需要该消息返回 void*，那么您可以从 NSString* 转换为 void*，然后再返回。

- (void*)reverseGeocoder:(Placemark*)myPlacemark
{
    // assuming myPlacemark is holding a reference to the dictionary (so no need to retain)
    NSString *city = [myPlacemark.addressDictionary objectForKey:kABPersonAddressCityKey];
    return (void*)city;
}

然后在分配它时将其转换回 NSString （不知道为什么要这样做）：

-(BOOL)fetchAndParseRss
{
    // you need to get myPlacemark from somewhere, presumably from the geocode request?
    Placemark * myPlacemark = [self getPlacemark];

    NSString * CurrentLocation = (NSString*)[self reverseGeocoder:myPlacemark];
}