尝试通过onConnected()方法获取当前位置 [英] Trying to get current location through onConnected() method

问题描述

我正在尝试通过onConnected()方法获取当前位置.但是不幸的是onMapReady()被更早调用.因此，如下面的日志所示，我的变量currentLatitude和currentLongitude包含值0.0:

I'm trying to get my current location through the onConnected() method. But unfortunately onMapReady() gets called earlier. Because of that my variables currentLatitude and currentLongitude contains the value 0.0 as you can see in the logs below:

I/System.out: currentLatitude : 0.0
I/System.out: currentLongitude : 0.0
D/: HostConnection::get() New Host Connection established 0xeec39820, tid 23599
I/System.out: onConnected

我已经尝试过使用AsyncTask，但这不起作用，因为onPreExecute()在onConnected()之前执行.在这里，您可以看到它的屏幕截图:

I had already tried to use AsyncTask but that doesn't work because onPreExecute() gets executed before the onConnected(). Here you can see a screenshot of it:

链接: http://i.imgur.com/Ur1ZGbb.png

在下面，您可以看到我的代码:

Here below you can see my code:

public class BreakDownOnMaps extends FragmentActivity implements
        GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener,
        LocationListener,
        OnMapReadyCallback {
    protected GoogleApiClient mGoogleApiClient;
    private LocationRequest mLocationRequest =  new LocationRequest();
    double currentLatitude;
    double currentLongitude;
    LatLng latLng;

    @TargetApi(Build.VERSION_CODES.M)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_break_down_on_maps);
        buildApi();
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }

    @Override
    protected void onStart() {
        super.onStart();
        mGoogleApiClient.connect();
    }

    @Override
    protected void onResume() {
        super.onResume();
        mGoogleApiClient.connect();
    }

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

    public void handleNewLocation(Location loc) {
        currentLatitude = loc.getLatitude();
        currentLongitude = loc.getLongitude();
        latLng = new LatLng(currentLatitude, currentLongitude);
        System.out.println("handleNewLocation ");
    }

    @Override
    public void onConnected(Bundle bundle) {
        System.out.println("onConnected");
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
                && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        }
        Location location = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
        if (location == null) {
            LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, (com.google.android.gms.location.LocationListener) this);
        }
        else {
            handleNewLocation(location);
        }
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        System.out.println("currentLatitude : " + currentLatitude);
        System.out.println("currentLongitude : " + currentLongitude);
        latLng = new LatLng(currentLatitude, currentLongitude);
        MarkerOptions options = new MarkerOptions()
                .position(latLng)
                .title("I am here!");
        googleMap.addMarker(options);
        googleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
    }

推荐答案

我通过对名为gMap的全局GoogleMap变量使用了setter方法来解决此问题.在handleNewLocation()内部，我使用变量gMap通过标记来确定我的位置.

I have fixed it by using a a setter method for my global GoogleMapvariable called gMap. Inside the handleNewLocation() I'm using the variable gMap to pinpoint where I am through using a marker.

这是完整的代码:

public class BreakDownOnMaps extends FragmentActivity implements
        GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener,
        LocationListener,
        OnMapReadyCallback {
    protected GoogleApiClient mGoogleApiClient;
    private LocationRequest mLocationRequest =  new LocationRequest();
    double currentLatitude;
    double currentLongitude;
    LatLng latLng;
    GoogleMap gMap;


    @TargetApi(Build.VERSION_CODES.M)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_break_down_on_maps);
        buildApi();
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }

    @Override
    protected void onStart() {
        super.onStart();
        mGoogleApiClient.connect();
    }
    @Override
    protected void onResume() {
        super.onResume();
        mGoogleApiClient.connect();
    }

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

    public void handleNewLocation(Location loc) {
        currentLatitude = loc.getLatitude();
        currentLongitude = loc.getLongitude();
        latLng = new LatLng(currentLatitude, currentLongitude);
        System.out.println("handleNewLocation ");
        MarkerOptions options = new MarkerOptions()
                .position(latLng)
                .title("I am here!");
        gMap.addMarker(options);
        gMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
    }

    @Override
    public void onConnected(Bundle bundle) {
        System.out.println("onConnected");
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
                && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        }
        Location location = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
        if (location == null) {
            LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, (com.google.android.gms.location.LocationListener) this);
        }
        else {
            handleNewLocation(location);
        };
    }

    @Override
    public void onConnectionSuspended(int i) {}

    @Override
    public void onLocationChanged(Location location) {
        handleNewLocation(location);
    }

    @Override
    public void onConnectionFailed(ConnectionResult connectionResult) {}

    @Override
    public void onMapReady(GoogleMap googleMap) {
        System.out.println("currentLatitude : " + currentLatitude);
        System.out.println("currentLongitude : " + currentLongitude);
        latLng = new LatLng(currentLatitude, currentLongitude);
        setgMap(googleMap);
        if(currentLatitude != 0 || currentLongitude != 0) {
            MarkerOptions options = new MarkerOptions()
                    .position(latLng)
                    .title("I am here!");
            googleMap.addMarker(options);
            googleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
        }
    }

    public GoogleMap getgMap() {
        return gMap;
    }

    public void setgMap(GoogleMap gMap) {
        this.gMap = gMap;
    }
}

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