从片段初始化时AndroidXMapFragment返回null

<fragment
    android:id="@+id/map"
    android:name="com.google.android.gms.maps.SupportMapFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

dependencies {
    implementation 'com.google.android.gms:play-services-maps:18.0.0'
}

<meta-data
    android:name="com.google.android.geo.API_KEY"
    android:value="YOUR_API_KEY"/>

SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
if (mapFragment == null) {
    FragmentManager fragmentManager = getSupportFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    mapFragment = SupportMapFragment.newInstance();
    fragmentTransaction.replace(R.id.map, mapFragment).commit();
}
mapFragment.getMapAsync(new OnMapReadyCallback() {
    @Override
    public void onMapReady(GoogleMap googleMap) {
        // 地图准备好了，可以进行操作
    }
});