2016-04-16 29 views
7

我試圖在我的應用程序內的谷歌地圖上顯示用戶的當前位置,但我不想隨着用戶移動而不斷更新位置。他的初始位置應該記錄並顯示,直到他關閉應用程序。我寫了下面的代碼是:使用谷歌地點在android中獲取onMapReady中的當前位置API

private GoogleMap mMap; 
protected GoogleApiClient mGoogleApiClient; 
Location mLastLocation; 
double lat =0, lng=0; 

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

    // Obtain the SupportMapFragment and get notified when the map is ready to be used. 
    SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager() 
      .findFragmentById(R.id.map); 
    mapFragment.getMapAsync(this); 


} 

private void buildGoogleApiClient() { 
    mGoogleApiClient = new GoogleApiClient.Builder(this) 
      .addConnectionCallbacks(this) 
      .addOnConnectionFailedListener(this) 
      .addApi(LocationServices.API) 
      .build(); 
} 


/** 
* Manipulates the map once available. 
* This callback is triggered when the map is ready to be used. 
* This is where we can add markers or lines, add listeners or move the camera. In this case, 
* we just add a marker near Sydney, Australia. 
* If Google Play services is not installed on the device, the user will be prompted to install 
* it inside the SupportMapFragment. This method will only be triggered once the user has 
* installed Google Play services and returned to the app. 
*/ 
@Override 
public void onMapReady(GoogleMap googleMap) { 
    mMap = googleMap; 

    // Add a marker in Sydney and move the camera 
    mMap.setMyLocationEnabled(true); 

    LatLng loc = new LatLng(lat, lng); 
    mMap.addMarker(new MarkerOptions().position(loc).title("New Marker")); 
    mMap.moveCamera(CameraUpdateFactory.newLatLng(loc)); 
} 

@Override 
public void onConnected(Bundle bundle) { 
    mLastLocation = LocationServices.FusedLocationApi.getLastLocation(
      mGoogleApiClient); 
    if (mLastLocation != null) { 
     lat = mLastLocation.getLatitude(); 
     lng = mLastLocation.getLongitude(); 
    } 
} 

@Override 
protected void onStart() { 
    super.onStart(); 

    mGoogleApiClient.connect(); 
} 

這段代碼的問題是,我得到了lat, lngonMapReady功能已執行完畢。我認爲解決此問題的方法之一是創建一個AsyncTask以確保在地圖之前檢索位置數據。但是,我試圖以不會使用AsyncTask的方式實現此功能。

回答

6

只是移動創建的標記從onMapReady()onConnected()代碼,以及呼叫buildGoogleApiClient()呼叫轉移從onCreate()onMapReady()

​​

雖然,注意,你經常會得到空從呼叫getLastLocation()。您可以使用requestLocationUpdates(),並在第一個位置進入時致電removeLocationUpdates()。 看一看this answer,它有一個完全示例,顯示您正在嘗試執行的操作。

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