如何使用GPS獲取用戶的位置

Question

我有一個活動，其中我有一個文本視圖，我想要顯示用戶的當前位置和特定地址之間的距離。我有地址的緯度和經度，但我的問題是獲取用戶的位置。我的目標是當活動創建時，我想要得到他的位置'沒有按任何按鈕。我已經嘗試了多種方式：getLastKnownLocation，onLocation已更改等，但返回的值始終爲空。

請務必注意，我正在模擬器上運行應用程序。

示例代碼：

protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_business_list); 

     Bundle bundleUser = getIntent().getExtras(); 
     final String owneruser = bundleUser.getString("username"); 

     Bundle bundleType = getIntent().getExtras(); 
     String type = bundleType.getString("type"); 

     locationManager = (LocationManager) getSystemService(LOCATION_SERVICE); 

     final TextView t = (TextView) findViewById(R.id.textView2); 
     listener = new LocationListener() { 
      @Override 
      public void onLocationChanged(Location location) { 
       longitude = location.getLongitude(); 
       latitude = location.getLatitude(); 
       t.append("\n " + location.getLongitude() + " " + location.getLatitude()); 
      } 

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

      } 

      @Override 
      public void onProviderEnabled(String s) { 

      } 

      @Override 
      public void onProviderDisabled(String s) { 

       Intent i = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS); 
       startActivity(i); 
      } 
     }; 
     final Location userLocation = new Location(""); 
     userLocation.setLatitude(latitude); 
     userLocation.setLongitude(longitude); 
} 

@Override 
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) { 
     switch (requestCode){ 
      case 10: 
       update(); 
       break; 
      default: 
       break; 
     } 
    } 

    void update(){ 
     // first check for permissions 
     if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) { 
      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) { 
       requestPermissions(new String[]{Manifest.permission.ACCESS_COARSE_LOCATION,Manifest.permission.ACCESS_FINE_LOCATION,Manifest.permission.INTERNET} 
         ,10); 
      } 
     } 
     else { 
      locationManager.requestLocationUpdates("gps", 5000, 0, listener); 
     } 
    } 

Answer 1

實現您的活動LocationListener的：

public class MyActivity extends AppCompatActivity implements LocationListener { 
private Location userLocation = new Location(""); 


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

     @Override 
public void onLocationChanged(Location location) { 
    if(location != null){ 
     userLocation.setLatitude(location.getLatitude()); 
     userLocation.setLongitude(location.getLongitude()); 
    } 
} 

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

} 

@Override 
public void onProviderEnabled(String provider) { 

} 

@Override 
public void onProviderDisabled(String provider) { 

} 
} 

嘗試使用此方法授予權限：

 if (ContextCompat.checkSelfPermission(context, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) { 
     // Should we show an explanation? 
     if (ActivityCompat.shouldShowRequestPermissionRationale(getActivity(), Manifest.permission.ACCESS_FINE_LOCATION)) { 
      // Show an expanation to the user *asynchronously* -- don't block this thread waiting for the user's response! After the user sees the explanation, try again to request the permission. 
     } else { 
      // No explanation needed, we can request the permission. 
      ActivityCompat.requestPermissions(getActivity(), new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, RC_ACCESS_FINE_LOCATION); 
      // MY_PERMISSIONS_REQUEST_READ_CONTACTS is an app-defined int constant. The callback method gets the result of the request. 
     } 
    } 

，並在您的清單補充一點：

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