ios - MKCoordinateRegionMakeWithDistance 抛出 "Thread 1: signal SIGABRT"

Question

我遇到了一个新问题，我不知道为什么...我进一步的解决方案是 Rob 发布的 here。我喜欢他的作品，在更新到 iOS 6.1 之前，它工作得很好。

- (void)loadKml:(NSURL *)url
{
    // parse the kml

    Parser *parser = [[Parser alloc] initWithContentsOfURL:url];
    parser.rowElementName = @"Placemark";
    parser.elementNames = @[@"name", @"Snippet", @"coordinates", @"description"];
    parser.attributeNames = @[@"img src="];
    [parser parse];

    // add annotations for each of the entries

    for (NSDictionary *locationDetails in parser.items)
    {
        MKPointAnnotation *annotation = [[MKPointAnnotation alloc] init];
        annotation.title = locationDetails[@"name"];
        annotation.subtitle = locationDetails[@"Snippet"];
        NSArray *coordinates = [locationDetails[@"coordinates"] componentsSeparatedByString:@","];
        annotation.coordinate = CLLocationCoordinate2DMake([coordinates[1] floatValue], [coordinates[0] floatValue]);
        [self.mapView addAnnotation:annotation];
    }

    // update the map to focus on the region that encompasses all of your annotations

    MKCoordinateRegion region;
    if ([self.mapView.annotations count] > 1)
    {
        region = [self regionForAnnotations:self.mapView.annotations];
        region = MKCoordinateRegionMake(region.center, MKCoordinateSpanMake(region.span.latitudeDelta * 1.05, region.span.longitudeDelta * 1.05));  // expand the region by 5%
    }
    else
    {
        id<MKAnnotation> annotation = self.mapView.annotations[0];
        region = MKCoordinateRegionMakeWithDistance(annotation.coordinate, 100.0, 100.0); // >>>this line throws: "Thread 1: signal SIGABRT"<<<
    }
    [self.mapView setRegion:region animated:YES];
}

自从更新到 iOS 6.1 Simulator 后，它就不能用了。

编辑:我得到这个错误:

*** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArrayM objectAtIndex:]: index 0 beyond bounds for empty array'

Answer 1

几个想法:

1. 您检查过以确保您的 IBOutlet给你的mapView连接了吗？如果self.mapView是nil ，应用可能会崩溃。

2. 你看过annotation.coordinate了吗？以确保您在那里获得有效结果？也许有一个 MKUserLocation还没有有效值；

3. 我知道是我给了你这个例程，但我注意到我们没有检查没有位置的情况。你可能想要这样的东西:

   if ([self.mapView.annotations count] > 0)
   {
       MKCoordinateRegion region;
       if ([self.mapView.annotations count] > 1)
       {
           region = [self regionForAnnotations:self.mapView.annotations];
           region = MKCoordinateRegionMake(region.center, MKCoordinateSpanMake(region.span.latitudeDelta * 1.05, region.span.longitudeDelta * 1.05));  // expand the region by 5%
       }
       else
       {
           id<MKAnnotation> annotation = self.mapView.annotations[0];
           region = MKCoordinateRegionMakeWithDistance(annotation.coordinate, 100.0, 100.0);
       }
       [self.mapView setRegion:region animated:YES];
   }
   

4. 顺便说一句，我注意到您正在使用:

   parser.attributeNames = @[@"img src="];
   

   这是在检索您的图片网址吗？我原以为那应该是:

   parser.attributeNames = @[@"src"];
   

   也许您对解析器做了一些更改，但是 attributeDict的 didStartElement永远不会有一个由 img src= 键控的对象.如果 XML 标记是 <img src="http://blah.blah.blah/0.jpg"> ，您要查找的属性名称就是 src .