[Based aandroid] Android uses GPS to retrieve users' geographical locations and listen for location changes

1 Locationactivity. Java
 2   /*  Locationactivity. Java
  3   * @ Author octobershiner
  4   * 2011 7 22
  5   * Se. Hit
  6   * One demonstration is to locate the user's location and listen for location changesCode 
  7   * */   
 8   Package Uni. location;
 9    
 10   Import Android. App. activity;
 11   Import Android. content. context;
 12   Import Android. Location. location;
 13   Import Android. Location. locationlistener;
14   Import Android. Location. locationmanager;
 15   Import Android. OS. Bundle;
 16   Import Android. OS. vibrator;
 17   Import Android. util. log;
 18   Import Android. widget. textview;
 19    
 20  Public   Class Locationactivity Extends Activity {
 21       /**  Called when the activity is first created.  */   
 22       //  Create an lcoationmanager object  
  23         Private Locationmanager manager;
24       Private   Static   Final String tag = "location Demo ";
 25 @ Override
 26       Public   Void Oncreate (bundle savedinstancestate ){
 27           Super . Oncreate (savedinstancestate );
 28 Setcontentview (R. layout. Main );
 29          //  Obtain system services,  
  30    Manager = (locationmanager) getsystemservice (context. location_service );
 31 Location = manager. getlastknownlocation (locationmanager. gps_provider );
 32           //  Obtain the device location for the first time  
  33    Updatelocation (location );
34           //  Important functions, listening for Data Testing  
  35    Manager. requestlocationupdates (locationmanager. gps_provider, 6000, 10,
 36 Locationlistener );
 37                           
 38 }
 39    /*  Update here to cancel GPS listening when the activity is not active  */   
 40         Public   Void Onpause (){
 41          Super . Onpause ();
 42 Locationmanager. removelistener (locationlistener );
 43 }
 44    
 45       //  Create an event listener  
  46       Private   Final Locationlistener = New Locationlistener (){
 47               Public   Void Onlocationchanged (location ){
 48 Updatelocation (location );
 49 }
 50               Public   Void Onproviderdisabled (string provider ){
 51 Updatelocation ( Null );
 52 Log. I (TAG, "provider now is disabled ..");
 53 }
 54               Public   Void Onproviderenabled (string provider ){
 55 Log. I (TAG, "provider now is enabled ..");
 56 }
 57               Public   Void Onstatuschanged (string provider, Int Status, bundle extras ){}
 58 };
 59        
 60   //  Obtain the user location function and use Log display.  
  61         Private   Void Updatelocation (location ){
 62 String latlng;
 63               If (Location! = Null ){
 64               Double Lat = location. getlatitude ();
 65               Double Lng = location. getlong.pdf ();
 66                
 67 Latlng = "latitude:" + lat + "longpolling:" + LNG;
 68 } Else {
 69 Latlng = "can't access your location ";
 70 }
 71 Log. I (TAG, "the location has changed ..");
 72 Log. I (TAG, "Your location:" + latlng );
 73 }
 74        
 75 }

Modifying only the activity file is not enough. Because the Android system is secure and the service is authorized, You need to modify the manifest. xml file.

 1   <?  XML version = "1.0" encoding = "UTF-8"  ?>   
 2   <  Manifest  Xmlns: Android  = "Http://schemas.android.com/apk/res/android"  
  3   Package  = "Uni. Location" 
  4   Android: versioncode  = "1"  
  5   Android: versionname  = "1.0"  >   
 6       <  Uses-SDK  Android: minsdkversion  = "8"     />   
7    
 8       <  Application  Android: icon  = "@ Drawable/icon"  Android: Label  = "@ String/app_name"  >   
 9           <  Activity  Android: Name  = ". Locationactivity"  
  10  Android: Label  = "@ String/app_name"  >   
 11               <  Intent-Filter  >   
 12                   <  Action  Android: Name  = "Android. Intent. Action. Main"     />   
 13                  <  Category  Android: Name  = "Android. Intent. Category. launcher"     />   
 14               </  Intent-Filter  >   
 15           </  Activity  >   
 16    
17       </  Application  >   
 18           <  Uses-Permission  Android: Name  = "Android. Permission. access_fine_location"     />    
 19   </  Manifest  >   

Many friends may have questions, that is, the debugging problem of GPS positioning on the android virtual machine. In fact, it can be simulated. You can start the virtual machine and then open the ddms interface, the device column on the left will dynamically display the startup status of various services on the Virtual Machine. After the virtual machine is unlocked, the emulator line under the Single-host device column will be displayed, at this time, you will find that the following emulator control has a location control. Open the manual label in it. Haha, I believe you have seen the longitude and latitude, and you can change it. Run yourProgramThen, click the send button set for the longitude and latitude to simulate the acceptance of the new geographic location.

In this demo, I used the log display status. We recommend this method for ease of use. If you want to know more, please refer to my other article.ArticleLearn how to use Log skillfully and search for sundyzlh's teaching video.

 

Click on log usage

Final Effect