Android MapView display empty

Question

Manifest:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.yu.lbs"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

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

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <uses-library android:name="com.google.android.maps" />

        <activity
            android:name="com.yu.lbs.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

main.xml:

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

    <com.google.android.maps.MapView
        android:id="@+id/mapView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:apiKey=".........."
        android:clickable="true"
        android:enabled="true" />

</LinearLayout>

MainActivity.java:

import android.os.Bundle;
import android.view.Menu;

import com.google.android.maps.MapActivity;

public class MainActivity extends MapActivity {

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

    @Override
    protected boolean isRouteDisplayed() {
        // TODO Auto-generated method stub
        return false;
    }

}

The Activity can be started. But in the MapView there is nothing. The small grid of map can be show, I think that comes with MapView, but no map is loaded. What could be wrong? I am using Google API v3. But this code is from a text book using API v1.

Answer 1

The way I got mine resolved, I had to do this:

final MapView mapView = (MapView)fragmentView.findViewById(R.id.map_fieldLocation);

mapView.onCreate(savedInstanceState);
mapView.getMapAsync(new OnMapReadyCallback() {

    @Override
    public void onMapReady(GoogleMap googleMap) {
        LatLng coordinates = new LatLng(match.match.LocationLatitude, match.match.LocationLongitude);
        googleMap.addMarker(new MarkerOptions().position(coordinates).title(match.match.LocationAddress));
        googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(coordinates, 15));
        mapView.onResume();
    }
});

The important part that I was missing is that you have to call the onCreate() method before you call getMapAsync() and once the callback is called, you need to call onResume() on the MapView object.

That totally solved it for me.

Here's what it would look like in your own class:

public class MainActivity extends MapActivity {

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

        if (getView() != null) {

            final MapView mapView = (MapView)getView().findViewById(R.id.mapView);

            mapView.onCreate(savedInstanceState);
            mapView.getMapAsync(new OnMapReadyCallback() {

                @Override
                public void onMapReady(GoogleMap googleMap) {
                    LatLng coordinates = new LatLng(match.match.LocationLatitude, match.match.LocationLongitude);
                    googleMap.addMarker(new MarkerOptions().position(coordinates).title(match.match.LocationAddress));
                    googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(coordinates, 15));
                    mapView.onResume();
                }
            }
        }
    }

    @Override
    protected boolean isRouteDisplayed() {
        // TODO Auto-generated method stub
        return false;
    }

}

Hope this helps!