目标c - 解析PFObject ID以映射注释标题和副标题

Question

我正在使用解析框架来收集类中的对象，并将它们显示在地图上。目前，注释标题显示"CreatedAt"字符串，字幕显示"坐标"。如何将标题和副标题更改为我设置的另一个PFObject ID？我的很多代码都基于Parse提供的GeoLocations应用程序。代码如下：

@interface GeoPointAnnotation()
@property (nonatomic, strong) PFObject *object;
@end
@implementation GeoPointAnnotation
- (id)initWithObject:(PFObject *)aObject {
    self = [super init];
    if (self) {
        _object = aObject;
        PFGeoPoint *geoPoint = self.object[@"coordinates"];
        [self setGeoPoint:geoPoint];
    }
    return self;
}

- (void)setGeoPoint:(PFGeoPoint *)geoPoint {
    _coordinate = CLLocationCoordinate2DMake(geoPoint.latitude, geoPoint.longitude);
    static NSDateFormatter *dateFormatter = nil;
    if (dateFormatter == nil) {
        dateFormatter = [[NSDateFormatter alloc] init];
        dateFormatter.timeStyle = NSDateFormatterMediumStyle;
        dateFormatter.dateStyle = NSDateFormatterMediumStyle;
    }
    static NSNumberFormatter *numberFormatter = nil;
    if (numberFormatter == nil) {
        numberFormatter = [[NSNumberFormatter alloc] init];
        numberFormatter.numberStyle = NSNumberFormatterDecimalStyle;
        numberFormatter.maximumFractionDigits = 3;
    }
    _title = [dateFormatter stringForObjectValue:self.object.createdAt];
    _subtitle = [NSString stringWithFormat:@"%@, %@", [numberFormatter stringFromNumber:[NSNumber numberWithDouble:geoPoint.latitude]],
                 [numberFormatter stringFromNumber:[NSNumber numberWithDouble:geoPoint.longitude]]];    
}
@end

Answer 1

通过用以下代码替换部分代码来修复它：

 static NSString *dateFormatter = nil;
if (dateFormatter == nil) {
    dateFormatter = [[NSString alloc] init];
}

然后这个：

_title = [dateFormatter stringByAppendingString:self.object[@"Name"]];
_subtitle = [dateFormatter stringByAppendingString:self.object[@"Location"]];