Question

代码：

CLLocationCoordinate2D coordinate = CLLocationCoordinate2DMake([[[NSUserDefaults standardUserDefaults] objectForKey:@"lat"] floatValue], [[[NSUserDefaults standardUserDefaults] objectForKey:@"lon"] floatValue]);
CLLocation *currentLocation = [[CLLocation alloc] initWithCoordinate:coordinate altitude:1 horizontalAccuracy:1 verticalAccuracy:-1 timestamp:nil];
[objects enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
    CLLocationCoordinate2D coordinate = CLLocationCoordinate2DMake([self.photos[idx][@"lat"] floatValue], [self.photos[idx][@"lon"] floatValue]);
    CLLocation *location = [[CLLocation alloc] initWithCoordinate:coordinate altitude:1 horizontalAccuracy:1 verticalAccuracy:-1 timestamp:nil];
    CLLocationDistance distance = [location distanceFromLocation:currentLocation]/1000;
}];

如果我NSLog当前位置和位置我得到相同的坐标，因为它们是相同的，有细微差别。位置为：lat：37.331581 lon：-122.030708，当前位置为：“lat”：“37.33154”，“lon”：“ - 122.0307”。如你所知，如果我从这两个地方得到距离，我应该得到0公里。但我得到的是12781.989811。这是为什么？我正在运行模拟器。如果是这种情况，或者我的代码错了？

Answer 1

减少问题，使问题变得尽可能简单有人试图回答的邮政编码可以运行我们没有您的userDefauts，这使问题无法再现添加显示问题的NSLog语句。

我怀疑如果你做这些事情，你将自己解决问题。

如何提出问题的示例：

CLLocationCoordinate2D coordinate1 = CLLocationCoordinate2DMake(37.331581, -122.030708);
CLLocation *location1 = [[CLLocation alloc] initWithCoordinate:coordinate1 altitude:1 horizontalAccuracy:1 verticalAccuracy:-1 timestamp:nil];

CLLocationCoordinate2D coordinate2 = CLLocationCoordinate2DMake(37.331581, -122.030708);
CLLocation *location2 = [[CLLocation alloc] initWithCoordinate:coordinate2 altitude:1 horizontalAccuracy:1 verticalAccuracy:-1 timestamp:nil];

CLLocationDistance distance1 = [location1 distanceFromLocation:location2]/1000;
NSLog(@"distance: %f", distance1);

CLLocationCoordinate2D coordinate3 = CLLocationCoordinate2DMake(37.33154, -122.0307);
CLLocation *location3 = [[CLLocation alloc] initWithCoordinate:coordinate3 altitude:1 horizontalAccuracy:1 verticalAccuracy:-1 timestamp:nil];

CLLocationDistance distance2 = [location1 distanceFromLocation:location3]/1000;
NSLog(@"distance: %f", distance2);

NSLog输出：

2013-11-06 09:28:17.661 Test-iOS[45090:70b] distance: 0.000000
2013-11-06 09:28:17.663 Test-iOS[45090:70b] distance: 0.004605

哦，没有错误！

最好的猜测是用户默认值不是您所期望的，或者枚举的输入不是您所期望的。

为什么相同的坐标使用distanceFromLocation获得更大的距离

1 个答案: