通过GPS数据反向地理信息编码, 得到当前位置信息
检查可用性
这属于基础知识, 不赘述, 总的来说,你的设备的支持要打开, 添加CoreLocation的framework, 引用头文件, 添加委托,然后, 好的实践是在使用前编程检查相关可用性:
- (CLLocationManager *)locationManager
{
if(!_locationManager){
if([CLLocationManager locationServicesEnabled]){
_locationManager = [[CLLocationManager alloc] init];
_locationManager.delegate = self;
_locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters;
CLAuthorizationStatus status = [CLLocationManager authorizationStatus];
if (status == kCLAuthorizationStatusNotDetermined) {
NSLog(@" not determined");
if([_locationManager respondsToSelector:@selector(requestWhenInUseAuthorization)]){
[_locationManager requestAlwaysAuthorization];
}
}else if (status == kCLAuthorizationStatusDenied) {
NSLog(@"denied");
}else if (status == kCLAuthorizationStatusRestricted) {
NSLog(@"restricted");
}else if (status == kCLAuthorizationStatusAuthorizedAlways) {
NSLog(@"always allowed");
}else if (status == kCLAuthorizationStatusAuthorizedWhenInUse) {
NSLog(@"when in use allowed");
}else{
}
}else _locationManager = nil;
}
return _locationManager;
}
注意kCLAuthorizationStatusNotDetermined状态, iOS8以后, 需要手动编辑info.plist文件, 添加两个请求用户授权时的文案, 才能正常使用, 这里觉得匪夷所思:
<key>NSLocationWhenInUseUsageDescription</key>
<string>请授权使用地理位置服务</string>
<key>NSLocationAlwaysUsageDescription</key>
<string>请授权使用地理位置服务</string>
以上, 可随便参考网上任何一篇教程
请求地理位置并反向编码
这里需要注意的是, 苹果的CLGeocoderAPI并不允许你频繁调用, 一分钟一次为宜, 所以你千万不要[self.locationManager startUpdatingLocation], 然后在locationManager:didChangeAuthorizationStatus:方法里去decode, 因为只是为了获取城市, 精度要求不高, 并且不需要持续更新, 所以我们就不update了, 只request一次, 然后在获取位置失败的时候再手动request一次:
+ (void)locationManager:(nonnull CLLocationManager *)manager didFailWithError:(nonnull NSError *)error{
NSLog(@"fail with error:\n %@", error);
[self.locationManager requestLocation];
}
相关解释参考这篇文章
语言的问题
因为习惯用英文系统, 就碰到请求回来的信息是英文的原因, 这里苹果是固化起来的, 暂时不支持用参数来指定返回数据的显示语言, 借鉴这篇文章的思路, 在请求前把当前语言设置保存起来, 临时改成中文, 请求结束后再修改回来:
+ (void)locationManager:(nonnull CLLocationManager *)manager didUpdateLocations:(nonnull NSArray *)locations{
CLLocation *location = [locations lastObject];
CLGeocoder *geocoder = [CLGeocoder new];
// 修改语言为中文
NSArray *currentLanguageArray = [[NSUserDefaults standardUserDefaults] objectForKey:@"AppleLanguages"];
[[NSUserDefaults standardUserDefaults] setObject: [NSArray arrayWithObjects:@"zh_Hans", nil] forKey:@"AppleLanguages"];
[geocoder reverseGeocodeLocation:location completionHandler:^(NSArray<CLPlacemark *> * __nullable placemarks, NSError * __nullable error) {
// 恢复语言
[[NSUserDefaults standardUserDefaults] setObject:currentLanguageArray forKey:@"AppleLanguages"];
if(error){
NSLog(@"reverse error:%@", [error localizedDescription]);
}else{
if([placemarks count] > 0){
CLPlacemark *mark = [placemarks firstObject];
NSLog(@"%@", mark);
NSLog(@"城市名:%@", mark.locality);
}
}
}];
}