2017-07-29 138 views
-1

我試圖從here建立一個應用程序,其中用戶點擊button並獲取當前的經度和緯度,但問題是我得到0.0緯度和經度。我在我的應用程序中有一個activity和一個service。對於activityservice的代碼下面給出:Toast消息顯示0經緯度

GpsActivity.java

public class GpsActivity extends AppCompatActivity { 

    Button show; 
    private static final int REQUEST_CODE_PERMISSION = 2; 
    String mPermission = Manifest.permission.ACCESS_FINE_LOCATION; 

    GPSTracker gps; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_gps); 

     try { 
      if (ActivityCompat.checkSelfPermission(this, mPermission) 
        != PackageManager.PERMISSION_GRANTED) { 

       ActivityCompat.requestPermissions(this, new String[]{mPermission}, 
         REQUEST_CODE_PERMISSION); 

//    If any permission above not allowed by user, this condition will 
//    execute every time, else your else part will work 
      } 
     } catch (Exception e) { 
      e.printStackTrace(); 
     } 

     show=(Button)findViewById(R.id.showLocation); 

     show.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       gps=new GPSTracker(GpsActivity.this); 

       // check if GPS enabled 
       if(gps.canGetLocation()){ 

        double latitude = gps.getLatitude(); 
        double longitude = gps.getLongitude(); 

        // \n is for new line 
        Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " 
          + latitude + "\nLong: " + longitude, Toast.LENGTH_LONG).show(); 
       }else{ 
        // can't get location 
        // GPS or Network is not enabled 
        // Ask user to enable GPS/network in settings 
        gps.showSettingsAlert(); 
       } 
      } 
     }); 
    } 
} 

GPSTracker.java

public class GPSTracker extends Service implements LocationListener { 
    private Context mContext; 

    // flag for GPS status 
    boolean isGPSEnabled = false; 

    // flag for network status 
    boolean isNetworkEnabled = false; 

    // flag for GPS status 
    boolean canGetLocation = false; 

    Location location; // location 
    double latitude; // latitude 
    double longitude; // longitude 

    // The minimum distance to change Updates in meters 
    private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters 

    // The minimum time between updates in milliseconds 
    private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute 

    protected LocationManager locationManager; 

    public GPSTracker() { 
     //mContext = null; 
    } 

    public GPSTracker(Context mContext) { 
     this.mContext = mContext; 
     getLocation(); 
    } 

    public Location getLocation() { 


     try { 
      locationManager = (LocationManager) mContext.getSystemService(LOCATION_SERVICE); 

      // getting GPS status 
      isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER); 

      // getting network status 
      isNetworkEnabled = locationManager 
        .isProviderEnabled(LocationManager.NETWORK_PROVIDER); 

      if (!isGPSEnabled && !isNetworkEnabled) { 
       // no network provider is enabled 
      } else { 
       this.canGetLocation = true; 
       // First get location from Network Provider 
       if (isNetworkEnabled) { 
        if (ActivityCompat.checkSelfPermission(this, 
          Manifest.permission.ACCESS_FINE_LOCATION) 
          != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, 
          Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) { 
         // TODO: Consider calling 
         // ActivityCompat#requestPermissions 
         // here to request the missing permissions, and then overriding 
         // public void onRequestPermissionsResult(int requestCode, String[] permissions, 
         //           int[] grantResults) 
         // to handle the case where the user grants the permission. See the documentation 
         // for ActivityCompat#requestPermissions for more details. 
         return location; 
        } 
        locationManager.requestLocationUpdates(
          LocationManager.NETWORK_PROVIDER, 
          MIN_TIME_BW_UPDATES, 
          MIN_DISTANCE_CHANGE_FOR_UPDATES, this); 

        Log.d("Network", "Network"); 
        if (locationManager != null) { 
         location = locationManager 
           .getLastKnownLocation(LocationManager.NETWORK_PROVIDER); 

         if (location != null) { 
          latitude = location.getLatitude(); 
          longitude = location.getLongitude(); 
         } 
        } 
       } 

       // if GPS Enabled get lat/long using GPS Services 
       if (isGPSEnabled) { 
        if (location == null) { 
         locationManager.requestLocationUpdates(
           LocationManager.GPS_PROVIDER, 
           MIN_TIME_BW_UPDATES, 
           MIN_DISTANCE_CHANGE_FOR_UPDATES, this); 

         Log.d("GPS Enabled", "GPS Enabled"); 
         if (locationManager != null) { 
          location = locationManager 
            .getLastKnownLocation(LocationManager.GPS_PROVIDER); 

          if (location != null) { 
           latitude = location.getLatitude(); 
           longitude = location.getLongitude(); 
          } 
         } 
        } 
       } 
      } 

     } catch (Exception e) { 
      e.printStackTrace(); 
     } 

     return location; 
    } 

    /** 
    * Stop using GPS listener 
    * Calling this function will stop using GPS in your app 
    * */ 

    public void stopUsingGPS(){ 
     if(locationManager != null){ 
      locationManager.removeUpdates(GPSTracker.this); 
     } 
    } 

    /** 
    * Function to get latitude 
    * */ 

    public double getLatitude(){ 
     if(location != null){ 
      latitude = location.getLatitude(); 
     } 

     // return latitude 
     return latitude; 
    } 

    /** 
    * Function to get longitude 
    * */ 

    public double getLongitude(){ 
     if(location != null){ 
      longitude = location.getLongitude(); 
     } 

     // return longitude 
     return longitude; 
    } 

    /** 
    * Function to check GPS/wifi enabled 
    * @return boolean 
    * */ 

    public boolean canGetLocation() { 
     return this.canGetLocation; 
    } 

    /** 
    * Function to show settings alert dialog 
    * On pressing Settings button will lauch Settings Options 
    * */ 

    public void showSettingsAlert(){ 
     AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext); 

     // Setting Dialog Title 
     alertDialog.setTitle("GPS is settings"); 

     // Setting Dialog Message 
     alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?"); 

     // On pressing Settings button 
     alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() { 
      public void onClick(DialogInterface dialog,int which) { 
       Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS); 
       mContext.startActivity(intent); 
      } 
     }); 

     // on pressing cancel button 
     alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() { 
      public void onClick(DialogInterface dialog, int which) { 
       dialog.cancel(); 
      } 
     }); 

     // Showing Alert Message 
     alertDialog.show(); 
    } 


    @Override 
    public IBinder onBind(Intent intent) { 
     // TODO: Return the communication channel to the service. 
     return null; 
    } 

    @Override 
    public void onLocationChanged(Location location) { 

    } 

    @Override 
    public void onStatusChanged(String s, int i, Bundle bundle) { 

    } 

    @Override 
    public void onProviderEnabled(String s) { 

    } 

    @Override 
    public void onProviderDisabled(String s) { 

    } 
} 

我所提到的所有的位置更新所需的permissionsmanifest文件。這裏唯一的問題是latitudelongitude在點擊按鈕時顯示0.0

一個人可以幫忙嗎?謝謝:)

+0

是U運行在Android模擬器的應用程序?在實際設備上運行 –

+0

應用程序,開啓GPS –

+0

我已經做到了,但它顯示0 –

回答

0

你也沒有告訴getLocation()方法

if(gps.canGetLocation()) 
{ 
    gps.getLocation(); 
    double latitude = gps.getLatitude(); 
    double longitude = gps.getLongitude(); 

    // \n is for new line 
    Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " 
      + latitude + "\nLong: " + longitude, Toast.LENGTH_LONG).show(); 
} 
+0

完成,但仍顯示'0.0'爲'latitude'和'longitude' –

+0

檢查logcat中是否有 – Ali

+0

例外印刷不,也不例外印刷的 –

0

功能getLastKnownLocation()將返回null。我建議等待一個新的位置在onLocationChanged()中被調用並使用該位置對象。

而且,你沒有正確使用Service類。你基本上創建了一個圍繞LocationManager的包裝。如果你想知道如何正確使用Service,看看這個tutorial