iphone - 将 nsnumber 或 nsstring 放入 initWithLatitude：

Question

我也被卡住了，也很愚蠢，我正在尝试将一个或NSString一个NSNumber放入initWithLatitude. CLLocation如果有人可以提供帮助，那就太好了。

这是代码

CLLocation *location1 = [[CLLocation alloc] initWithLatitude:53.778702 longitude:-0.271887];
CLLocation *location2 = [[CLLocation alloc] initWithLatitude:53.683267 longitude:-0.011330];
label.text = [NSString stringWithFormat:@"Distance in miles: %4.1f", [location1 distanceFromLocation:location2]/1609.344]; 
[location1 release];

我正在尝试替换[[CLLocation alloc] initWithLatitude:53.778702 longitude:-0.271887]为[[CLLocation alloc] initWithLatitude:lat longitude:lon]

Answer 1

CLLocationDegrees是 a double，所以你做

[[CLLocation alloc] initWithLatitude:[someNSNumber doubleValue] longitude:[someNSString doubleValue]];

Answer 2

你为什么不使用CLLocationDegrees数据类型来操作你的位置值？该类型只是普通的双精度数据类型

/*
 *  CLLocationDegrees
 *  
 *  Discussion:
 *    Type used to represent a latitude or longitude coordinate in degrees under the WGS 84 reference
 *    frame. The degree can be positive (North and East) or negative (South and West).  
 */
typedef double CLLocationDegrees;

Answer 3

CLLocation *loc = [[CLLocation alloc] initWithLatitude: (CLLocationDegrees) [lat doubleValue] longitude: (CLLocationDegrees) [lon doubleValue]];

无论是 NSStrings 还是 NSNumbers lat，这都有效。lon