谷歌地图片段内的片段可以操纵我的地图

Question

我正在尝试在另一个片段中显示一个谷歌地图片段，但是我无法操纵地图，我已经把我看到的所有步骤都放在了上面 the documentation，但我无法操作我的地图。

XML 代码：

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".FragmentoPrincipalUsuario">

<!-- TODO: Update blank fragment layout -->


<LinearLayout
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal|top">

    <fragment
        android:id="@+id/map"
        android:layout_width="match_parent"
        android:layout_height="391dp"
        class="com.google.android.gms.maps.MapFragment"
        android:layout_alignParentBottom="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="60dp" />

</LinearLayout>

<LinearLayout
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="149dp"
    android:layout_gravity="center_horizontal|bottom">

    <Button
        android:layout_width="117dp"
        android:layout_height="wrap_content"
        android:text="pedir taxi"
        android:id="@+id/pedirTaxi"
        android:layout_gravity="center_horizontal" />

</LinearLayout>

类片段代码：

public class FragmentoPrincipalUsuario extends Fragment implements OnMapReadyCallback  {

    private OnFragmentInteractionListener mListener;
    private List<ParseUser> mChoferes;
    private ParseUser       mUsuarioActual;
    private Button          mPedido;
    private GoogleMap map;


    public FragmentoPrincipalUsuario() {
        // Required empty public constructor
    }


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

        //conseguir usuario actual
       // mUsuarioActual = ParseUser.getCurrentUser();

        View x = inflater.inflate(R.layout.fragmento_principal_usuario, container, false);




        //evento boton pedir taxi
        mPedido.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                ParseQuery<ParseUser> query = ParseUser.getQuery();
                query.whereEqualTo("tipoUsuario", "chofer");
                query.findInBackground(new FindCallback<ParseUser>() {
                    public void done(List<ParseUser> choferes, com.parse.ParseException e) {
                        if (e == null) {

                            mChoferes = choferes;
                            String nombreChofer;

                            for (ParseUser chofer : mChoferes) {

                                nombreChofer = chofer.getUsername();

                                ParseObject gameScore = new ParseObject("Viaje");
                                gameScore.put("cliente", "hola");
                                gameScore.put("chofer", nombreChofer);
                                gameScore.put("tomado", false);
                                gameScore.saveInBackground();


                            }
                        } else {
                            // Something went wrong.
                        }
                    }
                });

            }
        });



        // Inflate the layout for this fragment
        return x;

    }


    // TODO: Rename method, update argument and hook method into UI event
    public void onButtonPressed(Uri uri) {
        if (mListener != null) {
            mListener.onFragmentInteraction(uri);

        }
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        if (context instanceof OnFragmentInteractionListener) {
            mListener = (OnFragmentInteractionListener) context;
        } else {
            throw new RuntimeException(context.toString()
                    + " must implement OnFragmentInteractionListener");
        }
    }

    @Override
    public void onDetach() {
        super.onDetach();
        mListener = null;
    }

    @Override
    public void onMapReady(GoogleMap map) {
        LatLng sydney = new LatLng(-27.7933121, -64.2574857);
        map.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
        map.moveCamera(CameraUpdateFactory.newLatLng(sydney));

    }


    /**
     * This interface must be implemented by activities that contain this
     * fragment to allow an interaction in this fragment to be communicated
     * to the activity and potentially other fragments contained in that
     * activity.
     * <p/>
     * See the Android Training lesson <a href=
     * "http://developer.android.com/training/basics/fragments/communicating.html"
     * >Communicating with Other Fragments</a> for more information.
     */
    public interface OnFragmentInteractionListener {
        // TODO: Update argument type and name
        void onFragmentInteraction(Uri uri);
    }

主要活动类代码：

public class DrawerPrincipal extends AppCompatActivity
    implements NavigationView.OnNavigationItemSelectedListener,FragmentoPrincipalUsuario.OnFragmentInteractionListener {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_drawer_principal);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    //cargar fragment principal usuario


    Fragment fragmento= null;
    fragmento = new FragmentoPrincipalUsuario();
   getSupportFragmentManager().beginTransaction()
           .replace(R.id.content_main, fragmento)
           .commit();



    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.setDrawerListener(toggle);
    toggle.syncState();

    NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);



}

@Override
public void onBackPressed() {
    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);
    } else {
        super.onBackPressed();
    }
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.pantalla_principal_usuario, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
    // Handle navigation view item clicks here.
    int id = item.getItemId();

    if (id == R.id.cuenta) {
        // Handle the camera action
    } else if (id == R.id.historial_viajes) {

    } else if (id == R.id.contacto) {

    } else if (id == R.id.compartir) {

    } else if (id == R.id.version) {

    } else if (id == R.id.salir) {

    }

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    drawer.closeDrawer(GravityCompat.START);
    return true;
}

@Override
public void onFragmentInteraction(Uri uri) {

}

}

编辑，调用 getMapAsync() 后，这里是堆栈跟踪：

空指针错误：

12-18 19:51:50.056 11265-11265/ar.com.taxiexpress.taxiexpress E/AndroidRuntime: 致命异常: main java.lang.RuntimeException: 无法开始活动 组件信息{ar.com.taxiexpress.taxiexpress/ar.com.taxiexpress.taxiexpress.DrawerPrincipal}： java.lang.NullPointerException 在 android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 在 android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 在 android.app.ActivityThread.access$600(ActivityThread.java:141) 在 android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 在 android.os.Handler.dispatchMessage(Handler.java:99) 在 android.os.Looper.loop(Looper.java:137) 在 android.app.ActivityThread.main(ActivityThread.java:5041) 在 java.lang.reflect.Method.invokeNative(Native Method) 在 java.lang.reflect.Method.invoke(Method.java:511) 在 com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 在 com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 在 dalvik.system.NativeStart.main(Native Method) 原因： java.lang.NullPointerException 在 ar.com.taxiexpress.taxiexpress.FragmentoPrincipalUsuario.onCreateView(FragmentoPrincipalUsuario.java:61) 在 android.support.v4.app.Fragment.performCreateView(Fragment.java:1962) 在 android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1067) 在 android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1248) 在 android.support.v4.app.BackStackRecord.run(BackStackRecord.java:738) 在 android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1613) 在 android.support.v4.app.FragmentController.execPendingActions(FragmentController.java:330) 在 android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:547) 在 android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1164) 在 android.app.Activity.performStart(Activity.java:5114) 在 android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2153) 在 android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 在 android.app.ActivityThread.access$600(ActivityThread.java:141) 在 android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 在 android.os.Handler.dispatchMessage(Handler.java:99) 在 android.os.Looper.loop(Looper.java:137) 在 android.app.ActivityThread.main(ActivityThread.java:5041) 在 java.lang.reflect.Method.invokeNative(Native Method) 在 java.lang.reflect.Method.invoke(Method.java:511) 在 com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 在 com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 在 dalvik.system.NativeStart.main(Native Method)

Answer 1

看起来主要问题是您没有调用 getMapAsync()。

由于您在 Fragment 中使用嵌套的 SupportMapFragment，因此您需要使用 getChildFragmentManager() 来获取 Map Fragment，然后调用 getMapAsync()。

SupportMapFragment mapFragment = ((SupportMapFragment) getChildFragmentManager()
            .findFragmentById(R.id.map));
mapFragment.getMapAsync(this);

不过，虽然这样可行，但最好让 Fragment 扩展 SupportMapFragment，这样就不需要嵌套 Fragments：

public class MyMapFragment extends SupportMapFragment 
                                    implements OnMapReadyCallback {

    private GoogleMap mMap;
    private Marker marker;


    public MyMapFragment () {
    }

    @Override
    public void onResume() {
        super.onResume();

        setUpMapIfNeeded();
    }

    private void setUpMapIfNeeded() {

        if (mMap == null) {

            getMapAsync(this);
        }
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {

        mMap = googleMap;
        setUpMap();
    }

    private void setUpMap() {

        mMap.setMyLocationEnabled(true);
        mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
        mMap.getUiSettings().setMapToolbarEnabled(false);


        mMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {

            @Override
            public void onMapClick(LatLng point) {

                //remove previously placed Marker
                if (marker != null) {
                    marker.remove();
                }

                //place marker where user just clicked
                marker = mMap.addMarker(new MarkerOptions().position(point).title("Marker")
                        .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_MAGENTA)));

            }
        });

    }

}