在片段中映射片段V2

Question

我在Google Map Fragments中面临一些问题"getmap()中的空指针Expcepttion".我想在片段中插入mapfragment请查看代码并告诉我是否正在使用正确的appraoch ..并让我知道我需要对我的代码做些什么来使其工作

我的布局文件:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent" 
  android:orientation="vertical"
  android:background="@drawable/bg2"
  android:weightSum="100">

<Button
    android:id="@+id/perx_button"
    android:layout_marginTop="70dip"
    android:layout_gravity="center"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/perx_card_btn" />

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

</LinearLayout>


public class PerxDetailedFragment extends SupportMapFragment {

  static final LatLng HAMBURG = new LatLng(53.558, 9.927);
  static final LatLng KIEL = new LatLng(53.551, 9.993);
 GoogleMap map;
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {

     FragmentTransaction ft = getFragmentManager().beginTransaction();

    map = ((SupportMapFragment) getFragmentManager().findFragmentById(R.id.map))
            .getMap();

    SupportMapFragment fmap = (SupportMapFragment) getFragmentManager().findFragmentById(R.id.map);

    if (fmap == null) {
        fmap = SupportMapFragment.newInstance();
        ft.add(R.id.map, fmap);
    }

    ft.commit();

    Marker hamburg = map.addMarker(new MarkerOptions().position(HAMBURG)
            .title("Hamburg"));
        Marker kiel = map.addMarker(new MarkerOptions()
            .position(KIEL)
            .title("Kiel")
            .snippet("Kiel is cool")
            .icon(BitmapDescriptorFactory
                .fromResource(R.drawable.ic_launcher)));

        // Move the camera instantly to hamburg with a zoom of 15.
        map.moveCamera(CameraUpdateFactory.newLatLngZoom(HAMBURG, 15));

        // Zoom in, animating the camera.
        map.animateCamera(CameraUpdateFactory.zoomTo(10), 2000, null);


     return inflater.inflate(R.layout.perx_detailed, null, false);
}
public void onActivityCreated(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);       


    }


}

Answer 1

您需要先扩充布局.问题是你在onCreateView结束时这样做,所以当你调用findFragmentById时,地图片段就不存在了.

此外,PerxDetailedFragment应该扩展Fragment,而不是SupportMapFragment.

public class PerxDetailedFragment extends Fragment {
    // ...

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

        View v = inflater.inflate(R.layout.perx_detailed, null, false);

        map = ((SupportMapFragment) getFragmentManager().findFragmentById(R.id.map))
            .getMap();

        //...

        return v;
    }