修复清单和代码后，MapFragment返回null

Question

我的activity_locateus文件有

<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/map"
    android:name="com.google.android.gms.maps.SupportMapFragment"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="1" />

清单文件

   <uses-sdk
        android:minSdkVersion="12"
        android:targetSdkVersion="21" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
    <uses-permission android:name="android.permission.GET_ACCOUNTS" />
    <uses-permission android:name="android.permission.CALL_PHONE" />
    <uses-permission android:name="android.permission.SEND_SMS" />
    <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <permission
        android:name="mypackage.permission.MAPS_RECEIVE"
        android:protectionLevel="signature" />

    <uses-permission android:name="mypackage.permission.MAPS_RECEIVE" />
    <uses-feature
        android:glEsVersion="0x00020000"
        android:required="true" />
    <application>
        <meta-data
            android:name="com.google.android.gms.version"
            android:value="@integer/google_play_services_version" />
        <meta-data
            android:name="com.google.android.maps.v2.API_KEY"
            android:value="myapikey" />
    </application>

活动代码

public class LocateUs extends FragmentActivity {
    private Double latitude, longitude;
    private String storeName, contactNumber;
    private LatLng location;
    private GoogleMap map;

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

    MapsInitializer.initialize(getApplicationContext());

    latitude = (Double) getIntent().getDoubleExtra("latitude",
        God.INVALID_GPS);
    longitude = (Double) getIntent().getDoubleExtra("longitude",
        God.INVALID_GPS);
    location = new LatLng(latitude, longitude);
    storeName = (String) getIntent().getStringExtra("storeName");
    contactNumber = (String) getIntent().getStringExtra("contactNumber");
    map = ((SupportMapFragment) getSupportFragmentManager()
        .findFragmentById(R.id.map)).getMap();
    if (map != null) {
        map.addMarker(new MarkerOptions()
            .position(location)
            .title(storeName)
            .snippet(contactNumber)
            .icon(BitmapDescriptorFactory
                .fromResource(R.drawable.app_logo)));
        map.moveCamera(CameraUpd"ateFactory.newLatLngZoom(location, 15));
        map.animateCamera(CameraUpdateFactory.zoomTo(10), 2000, null);
    } else
        Log.e(God.LOG_TAG, "Map is null");
    }
}