Question

我正在尝试在地图上添加标记。但.search()返回null。

可能是什么问题？

ActivityPlace.java

initializeMap()

activity_place.xml

public class ActivityPlace  extends AppCompatActivity {

    GoogleMap mMap;
    LatLng latlng;

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


        if (initializeMap() && checkServices()) {
                latlng = new LatLng(latitude, longitude);
                MarkerOptions options = new MarkerOptions().position(latlng);
                Marker marker = mMap.addMarker(options);
                CameraUpdate update = CameraUpdateFactory.newLatLngZoom(latlng, 12);
                mMap.animateCamera(update);
                mMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
                    @Override
                    public void onMapClick(LatLng latLng) {
                        //Launch Map Page
                    }
                });
        }
    }

    /*
    Method to check Google services before initiating map
 */
    public boolean checkServices() {
        int isAvailable = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
        if (isAvailable == ConnectionResult.SUCCESS){
            return true;
        }else if (GooglePlayServicesUtil.isUserRecoverableError(isAvailable)){
            Dialog dialog = GooglePlayServicesUtil.getErrorDialog(isAvailable, this, ERROR_DIALOG_REQUEST);
            dialog.show();
        }else {
            Toast.makeText(this, "Cant connect to mapping service", Toast.LENGTH_SHORT).show();
        }
        return false;
    }

    /*
        Initialize the map and get a handle to the map to set its location
     */
    private boolean initializeMap() {
        if (mMap == null) {
            SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map_fragment);

            mapFragment.getMapAsync(new OnMapReadyCallback() {
                @Override
                public void onMapReady(GoogleMap googleMap) {
                    mMap = googleMap;
                }
            });
        }
        return (mMap != null);
    }
}

activity_map_embedded_fragment.xml

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

    <ScrollView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent">

        <LinearLayout
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:orientation="vertical"
            android:id="@+id/place_layout">

            <TextView
                style="@style/txtPrimaryHeading"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:padding="8dp"
                android:id="@+id/place_name"/>

            <include
                android:id="@+id/map"
                layout="@layout/activity_map_embedded_fragment"
                android:layout_width="match_parent"
                android:layout_height="200dp" />
        </LinearLayout>
    </ScrollView>

</RelativeLayout>

Answer 1

getMapAsync是异步调用，它将在后台运行，您的方法将仅返回false值。

我的建议是在调用onMapReady时执行其他操作。

mapFragment.getMapAsync(new OnMapReadyCallback() {
    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;

        latlng = new LatLng(latitude, longitude);
        MarkerOptions options = new MarkerOptions().position(latlng);
        Marker marker = mMap.addMarker(options);
        CameraUpdate update = CameraUpdateFactory.newLatLngZoom(latlng, 12);
        mMap.animateCamera(update);
        mMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
            @Override
            public void onMapClick(LatLng latLng) {
                //Launch Map Page
            }
        });
    }
});

Answer 2

在初始化地图之前调用它。

GoogleApiClient mGoogleApiClient ;


synchronized void buildGoogleApiClient() {
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();
if (mGoogleApiClient != null) {
            mGoogleApiClient.connect();
        }

}

Answer 3

试试这个。它确实有效。

GoogleApiClient mGoogleApiClient ;


synchronized void buildGoogleApiClient() {
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();
if (mGoogleApiClient != null) {
            mGoogleApiClient.connect();
        }

}

GoogleMap对象为空

3 个答案: