ios - MKMapView addAnnotation 不起作用

Question

我需要一些帮助，因为 addAnnotations 不适用于以下代码:

NSString *postString = [[NSString alloc]initWithFormat:@"MM_act=%@",@"test"];
NSData *returnData = [requestURLData:@"location.php" postString:postString];
NSString *result = [[NSString alloc]initWithData:returnData encoding:NSUTF8StringEncoding];
//return JSON
if (![result isEqualToString:@""]) {
    NSMutableArray *ann_array = [[NSMutableArray alloc] init];
    NSError *error = nil;
    id object = [NSJSONSerialization JSONObjectWithData:returnData options:NSJSONReadingMutableContainers error:&error];
    if ([object isKindOfClass:[NSDictionary class]]) {
        NSDictionary *jsonDictF = object;
        NSArray *arrayId = [jsonDictF objectForKey:@"Id"];
        NSArray *arrayLati = [jsonDictF objectForKey:@"Latitude"];
        NSArray *arrayLong = [jsonDictF objectForKey:@"Longitude"];
        for (int i=0; i<[arrayId count]; i++) {
            CLLocationCoordinate2D currentLocation = CLLocationCoordinate2DMake([[[NSString alloc] initWithFormat:@"%@",[arrayLati objectAtIndex:i]] floatValue], [[[NSString alloc] initWithFormat:@"%@",[arrayLong objectAtIndex:i]] floatValue]);
            NSString *ID = [[NSString alloc] initWithFormat:@"%@",[arrayId objectAtIndex:i]];
            MyAnnotation *annotation = [[MyAnnotation alloc] initWithCoordinate:currentLocation Title:@"test" AndSubtitle:@"" annIdentifier:ID];
            [ann_array addObject:annotation];
        }
        [m_mapView addAnnotations:ann_array];
    }
}

但是我在调​​试区可以看到注释数据，怎么了？请帮助我。

Answer 1

您确定您设置的位置在 map 的当前可见区域中吗？您是否滚动查看它是否已添加？

简单地向 map 添加注释并不会放大该注释。您可以使用以下方法放大新添加的注释:

-(void)zoomInOnLocation:(CLLocationCoordinate2D)location
{
    MKCoordinateRegion region = MKCoordinateRegionMakeWithDistance(location, 200, 200);
    [self.map setRegion:[self.map regionThatFits:region] animated:YES];
}