CLLocationManager定位经纬度

CLLocationManager 

CLLocationManager使用步骤 
1.创建一个CLLocationManager实例 
CLLocationManager *locationManager = [[CLLocationManager alloc] init]; 
2.设置CLLocationManager实例委托和精度 
locationManager.delegate = self; 
locationManager.desiredAccuracy = kCLLocationAccuracyBest; 
3.设置距离筛选器distanceFilter，下面表示设备至少移动1000米，才通知delegate 
locationManager.distanceFilter = 1000.0f; 
或者没有筛选器的默认设置： 
locationManager.distanceFilter = kCLDistanceFilterNone; 
4.启动请求 
[locationManager startUpdatingLocation]; 
5.停止请求 
[locationManager stopUpdatingLocation]; 
罗盘功能 
1.通过CLLocationManagerDelegate的- (void)locationManager:(CLLocationManager *)manager 
didUpdateHeading:(CLHeading *)newHeading 获取当前用户手机与地磁北极或者地理北极的夹角。 
夹角范围[0, 360) 
0-north 90-east 180-south 
2.将罗盘上的指南针旋转一定角度 
CGFloat heading = (-1.0f*M_PI*newHeading.trueHeading)/180.f; 
self.circleView.transform = CGAffineTransformMakeRotation(heading); 
注意事项： 
1.CLLocationManager用于获取当前位置，定位有相当大的误差。如果app不需要实时的获取位置信息且 
使用了MKMapView, 则使用MKMapView获取当前位置，这个位置比较准确 
2.desiredAccuracy适合需求就可以了，并不是都需要最佳的精度。 
3.当不需要更新位置信息的时候，一定要停止。 
MKReverseGeocoder查询地理位置信息，包括国家、城市、区域等等 
1.实例MKReverseGeocoder 
MKReverseGeocoder *geocoder = [[MKReverseGeocoder alloc] initWithCoordinate:coordinate]; 
geocoder.delegate = self; 
[geocoder start]; 
2.在MKReverseGeocoderDelegate方法中获取placemark信息 
- (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFindPlacemark:(MKPlacemark *)placemark 成功查询出了地理位置信息 
- (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFailWithError:(NSError *)error 获取失败 
注意事项: 
不需要的时候一定要调用cancel方法，停止查询 
MKMapView MapKit地图控件 
可以使用在map上显示圆. 点, 大头针,画路径等。 
1.MKMapViewDelegate的常用回掉方法 
- (void)mapView:(MKMapView *)mapView regionWillChangeAnimated:(BOOL)animated; 
- (void)mapView:(MKMapView *)mapView regionDidChangeAnimated:(BOOL)animated; 
- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation; 
- (void)mapView:(MKMapView *)mapView didAddAnnotationViews:(NSArray *)views; 
// mapView:annotationView:calloutAccessoryControlTapped: is called when the user taps on left & right callout accessory UIControls. 
- (void)mapView:(MKMapView *)mapView annotationView:(MKAnnotationView *)view calloutAccessoryControlTapped:(UIControl *)control; 
- (void)mapView:(MKMapView *)mapView didSelectAnnotationView:(MKAnnotationView *)view; 
- (void)mapView:(MKMapView *)mapView didDeselectAnnotationView:(MKAnnotationView *)view; 
- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay; 
// Called after the provided overlay views have been added and positioned in the map. 
- (void)mapView:(MKMapView *)mapView didAddOverlayViews:(NSArray *)overlayViews __OSX_AVAILABLE_STARTING(__MAC_NA,__IPHONE_4_0); 
2.mapview缩小的时候, 有时后不会回掉regionDidChangeAnimated这个方法，可以通过添加gesturerecognizer检测这个时间。 
但必须实现UIGestureRecognizerDelegate的 
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer方法 
以添加大头针为例 
1.创建一个自定义的MKPinAnnotation类，必须遵守MKAnnotation协议 
2.在mapview上添加一个MKPinAnnotation是实例 
MKPintAnnotation *pinAnnotation = [[MKPintAnnotation alloc] initWithCoordinate:_currentCoordinate]; 
pinAnnotation.title = @"PIN-TITLE"; 
pinAnnotation.subtitle = @"PIN_SUBTITLE"; 
[_mapView addAnnotation:pinAnnotation]; 
3.实现- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation { 
MKPinAnnotationView *pinView = [[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:pinIdentifier] autorelease]; 
pinView.animatesDrop = TRUE; 
pinView.pinColor = MKPinAnnotationColorRed;//MKPinAnnotationColorGreen; 
pinView.canShowCallout = TRUE; 
UIButton *button = [UIButton buttonWithType:UIButtonTypeDetailDisclosure]; 
button.frame = CGRectMake(0, 0, 25, 25); 
pinView.rightCalloutAccessoryView = button; 
} 
注意事项: 
实际使用的时候在添加overlay和annotation的时候需要先移除mapview上已经有的overlays和annotations，避免叠加在一起了。 
使用Google API在mapview上画路径 
在mapview画指定两点之间的路径的原理和在地图上添加一个overlayview是相同的,关键是获取路径的数据. 
一般路径数据是经纬度的数据，需要转化成mapview上的的mkmappoint数据类型的。 
1.调用Google API获取两点之间的路径数据,详见http://code.google.com/apis/maps/documentation/directions/ 
2.解析路径数据(json格式)，将经纬度的点转化为mkmapoint 
3.在mapview上加个polygon line overlay 
MKPolyline *routeLine = [MKPolyline polylineWithPoints:points count:numberOfPoints; 
[_mapView addOverlay:routeLine]; 
[_mapView setVisibleMapRect:routeVisableRegion animated:YES]; 
4.实现 
- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay { 
MKPolygonView *overlayPolygonView = nil; 
if ([overlay isKindOfClass:[MKPolyline class]]) { 
CGFloat lineWidth = 6; 
UIColor *fillColor = [UIColor redColor]; 
UIColor *strokeColor = [UIColor greenColor]; 
overlayPolygonView = [[[MKPolylineView alloc] initWithPolyline:overlay] autorelease]; 
overlayPolygonView.fillColor = fillColor; 
overlayPolygonView.strokeColor = strokeColor; 
overlayPolygonView.lineWidth = lineWidth; 
} 
return overlayPolygonView; 
}