从未在Fragment中调用MapView.onMapReady以在MapView中加载Google Map

Question

我将尝试在我的Android应用程序中显示一个名为的片段的地图RoeteFragment.如果我调试我的代码,我发现onMapReady永远不会调用该方法,因此不会加载地图.

片段实现了OnMapReadyCallback所需的,在onCreateView我得到MapView和调用getMapAsync.如果我在该方法上放置断点,它将始终被击中,内部的断点onMapReady从未被击中.没有异常抛出.

我还在该文件中提供了有效的Google Maps API密钥res/values/google_maps_api.xml.

这是我的代码:

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

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

</RelativeLayout>

public class RoeteFragment extends Fragment implements OnMapReadyCallback {

    private MapView mapView;
    private static Roete _roete;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_roete, container, false);
        mapView = (MapView) view.findViewById(R.id.map);
        mapView.getMapAsync(this);
        return view;
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {

        if (_roete != null && _roete.getAankomstLocatie() != null && _roete.getVertrekLocatie() != null) {
            LatLng aankomst = new LatLng(_roete.getAankomstLocatie().getLatitude(), _roete.getAankomstLocatie().getLongitude());
            googleMap.addMarker(new MarkerOptions().position(aankomst).title("aankomst"));
            googleMap.moveCamera(CameraUpdateFactory.newLatLng(aankomst));

            LatLng vertrek = new LatLng(_roete.getVertrekLocatie().getLatitude(), _roete.getVertrekLocatie().getLongitude());
            googleMap.addMarker(new MarkerOptions().position(vertrek).title("vertrek"));
            googleMap.moveCamera(CameraUpdateFactory.newLatLng(vertrek));
        }
    }

    public static Fragment newInstance() {
        return new RoeteFragment ();
    }

    public static Fragment newInstance(Roete roete) {
        _roete = roete;
        return newInstance();
    }
}

你可以在我的代码中提交错误吗？

Answer 1

阅读MapView文档.特别:

这个类的用户必须转发来自所有生命周期方法Activity或Fragment含有此视图在这个类的相应的一些.特别是,您必须转发以下方法:

• onCreate(Bundle)
• onResume()
• onPause()
• onDestroy()
• onSaveInstanceState()
• onLowMemory()

Answer 2

地图片段是您扩展到另一个片段的布局的一部分（我们称之为父片段）。膨胀的片段成为父片段的活动而非活动的子片段。您必须询问父片段的子片段管理器：

注意：只需扩展简单的片段 public class MapsFragments extends Fragment implements OnMapReadyCallback {} XML 文件

<fragment xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:map="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/map"
    android:name="com.google.android.gms.maps.SupportMapFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="net.elektrasoft.Test.MapsFragments" />

和

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    Log.d("check","onCreateView");
    // Inflate the layout for this fragment
    View view= inflater.inflate(R.layout.fragment_maps_fragments, container, false);
    // Gets the MapView from the XML layout and creates it
    final SupportMapFragment myMAPF = (SupportMapFragment) getChildFragmentManager()
            .findFragmentById(R.id.map);
    myMAPF.getMapAsync(this);
    return  view;
}`