使用android檢索GPS位置

Question

我想要使用簡單的android程序獲取當前位置的GPS位置。我爲此使用了onLocationChanged()方法。但它返回的座標爲0.0。用戶權限部分是正確的。這是主要的代碼。

public class MainActivity extends Activity { 

GPSTracker gps; 

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

    Button btn = (Button) findViewById(R.id.button1); 
    final TextView tv = (TextView) findViewById(R.id.textView1); 

    btn.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View v) { 
      // TODO Auto-generated method stub 

      gps = new GPSTracker(MainActivity.this); 

      double lat = gps.latitude; 

      String mlat = String.valueOf(lat); 

      tv.setText(mlat); 
     } 
    }); 
} 



} 

這是使用，即時通訊GPS定位類...

public class GPSTracker extends Service implements LocationListener{ 

private final Context mContext; 
boolean isGPSEnabled = false; 
boolean canGetLocation = false; 

Location location; 
double latitude; 
double longtitude; 

protected LocationManager locationManager; 

public GPSTracker(Context context){ 

    this.mContext = context; 
    getLocation(); 

} 

public Location getLocation(){ 


     locationManager = (LocationManager) mContext.getSystemService(LOCATION_SERVICE); 
     locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this); 

     return null; 
} 

protected void onStart() { 

} 

protected void onPause(){ 

    locationManager.removeUpdates(this); 
} 


@Override 
public void onLocationChanged(Location location) { 
    // TODO Auto-generated method stub 

    latitude = location.getLatitude(); 
    longtitude = location.getLongitude(); 
} 

@Override 
public void onProviderDisabled(String provider) { 
    // TODO Auto-generated method stub 

} 

@Override 
public void onProviderEnabled(String provider) { 
    // TODO Auto-generated method stub 

} 

@Override 
public void onStatusChanged(String provider, int status, Bundle extras) { 
    // TODO Auto-generated method stub 

} 

@Override 
public IBinder onBind(Intent arg0) { 
    // TODO Auto-generated method stub 
    return null; 
} 

} 

Answer 1

你可以找到位置要麼GPS_PROVIDER或Android的

位置服務NETWORK_PROVIDER

概述

這裏使用GPS查找位置的一個示例，如果您的GPS不可用，則嘗試使用網絡查找位置

GPSTracker.java

public class GPSTracker extends Service implements LocationListener { 

private final 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 

// Declaring a Location Manager 
protected LocationManager locationManager; 

public GPSTracker(Context context) { 
    this.mContext = context; 
    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; 
      if (isNetworkEnabled) { 
       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 void onLocationChanged(Location location) { 
} 

@Override 
public void onProviderDisabled(String provider) { 
} 

@Override 
public void onProviderEnabled(String provider) { 
} 

@Override 
public void onStatusChanged(String provider, int status, Bundle extras) { 
} 

@Override 
public IBinder onBind(Intent arg0) { 
    return null; 
} 
} 

活動-AndroidGPSTrackingActivity.java

public class AndroidGPSTrackingActivity extends Activity { 

Button btnShowLocation; 

// GPSTracker class 
GPSTracker gps; 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 

    btnShowLocation = (Button) findViewById(R.id.btnShowLocation); 

    // show location button click event 
    btnShowLocation.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View arg0) {   
      // create class object 
      gps = new GPSTracker(AndroidGPSTrackingActivity.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(); 
      } 

     } 
    }); 
} 
} 

佈局 - main.xml中

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    android:orientation="vertical" > 

    <Button android:id="@+id/btnShowLocation" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="Show Location" 
     android:layout_centerVertical="true" 
     android:layout_centerHorizontal="true"/> 

</RelativeLayout> 


<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> 
    <uses-permission android:name="android.permission.INTERNET" />