CLLocationManager 獲取 GPS 位置信息

 http://magicalboy.com/ios_gps_location/

 

在 iOS 平台上使用 CLLocationManager 獲取 GPS 位置信息，比如經度，緯度，海拔高度等是很簡單的事情。

步驟

1. 加入 CoreLocation.framework , 導入頭文件。

   #import <CoreLocation/CoreLocation.h>

2. 在 AppDelegate.m 中加入檢測是否啟用位置服務功能。
   
   CLLocationManager * manager = [[ CLLocationManager alloc ] init ];

        if ( manager . locationServicesEnabled == NO ) {

            UIAlertView * servicesDisabledAlert = [[ UIAlertView alloc ] initWithTitle: @"Location Services Disabled" message: @"You currently have all location services for this device disabled. If you proceed, you will be asked to confirm whether location services should be reenabled." delegate: nil cancelButtonTitle: @"OK" otherButtonTitles: nil ];

            [ servicesDisabledAlert show ];

            [ servicesDisabledAlert release ];

        }

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1. 打開位置管理器。
   
   - ( IBAction ) openGPS: ( id ) sender {

        if ( locationManager == nil ) {

            locationManager = [[ CLLocationManager alloc ] init ];

            locationManager . delegate = self ;

            locationManager . desiredAccuracy = kCLLocationAccuracyBest ; // 越精確，越耗電！

        }

       

        [ locationManager startUpdatingLocation ]; // 開始定位

   }

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2. 在 CLLocationManagerDelegate 中獲取 GPS 位置信息。
   
   #pragma mark - CLLocationManagerDelegate

   - ( void ) locationManager: ( CLLocationManager * ) manager didFailWithError: ( NSError * ) error {

        switch ( error . code ) {

            case kCLErrorLocationUnknown:

                NSLog ( @"The location manager was unable to obtain a location value right now." );

                break ;

            case kCLErrorDenied:

                NSLog ( @"Access to the location service was denied by the user." );

                break ;

            case kCLErrorNetwork:

                NSLog ( @"The network was unavailable or a network error occurred." );

                break ;

            default :

                NSLog ( @"未定義錯誤" );

                break ;

        }

   }

    

   - ( void ) locationManager: ( CLLocationManager * ) manager didUpdateToLocation: ( CLLocation * ) newLocation fromLocation: ( CLLocation * ) oldLocation

   {

        NSLog ( @"oldLocation.coordinate.timestamp:%@" , oldLocation . timestamp );

        NSLog ( @"oldLocation.coordinate.longitude:%f" , oldLocation . coordinate . longitude );

        NSLog ( @"oldLocation.coordinate.latitude:%f" , oldLocation . coordinate . latitude );

       

        NSLog ( @"newLocation.coordinate.timestamp:%@" , newLocation . timestamp );

        NSLog ( @"newLocation.coordinate.longitude:%f" , newLocation . coordinate . longitude );

        NSLog ( @"newLocation.coordinate.latitude:%f" , newLocation . coordinate . latitude );

       

        NSTimeInterval interval = [ newLocation . timestamp timeIntervalSinceDate: oldLocation . timestamp ];

        NSLog ( @"%lf" , interval );

       

        // 取到精確GPS位置后停止更新

        if ( interval < 3 ) {

            // 停止更新

            [ locationManager stopUpdatingLocation ];

        }

       

        latitudeLabel . text = [ NSString stringWithFormat: @"%f" , newLocation . coordinate . latitude ];

        longitudeLabel . text = [ NSString stringWithFormat: @"%f" , newLocation . coordinate . longitude ];

   }

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完整 Demo

GPS_iOS