Question

我正在开发一个应用程序，该应用程序的顶部有一个菜单，并且菜单内有一些按钮。我正在尝试将Google Maps添加到按钮之一，我尝试了以下代码，但没有显示地图。我也尝试调试我的代码，但找不到任何问题。

这是主要活动：

    private DrawerLayout dr;
    private ActionBarDrawerToggle toggle;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_ACTION_BAR);
        setContentView(R.layout.activity_main2);

       //drawerLayout
        dr=(DrawerLayout)findViewById(R.id.draw);
       toggle=new ActionBarDrawerToggle(this,dr,R.string.Open,R.string.Close);

       dr.addDrawerListener(toggle);
       NavigationView navigationView =(NavigationView)findViewById(R.id.navigate);
       toggle.syncState();
       getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        SetUpDrawer(navigationView);
}

菜单：

    @Override
    public boolean onOptionsItemSelected(MenuItem item)
    {
        if(toggle.onOptionsItemSelected(item))
        {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
    public void selectDrawer(MenuItem menu)
    {
        Fragment myfragmenet =null;
        Class FragmentClass = null;
        switch (menu.getItemId())
        {
            case R.id.VoirHotel:
                FragmentClass=Hotels.class;
                break;
            case R.id.filter:
                FragmentClass=Filter.class;
                break;
            case R.id.carte:
                FragmentClass=Maps.class;
        }
        try {
            myfragmenet=(Fragment)FragmentClass.newInstance();
        } catch (Exception e) {
            e.printStackTrace();
        }
        FragmentManager fragmentManager=getSupportFragmentManager();
        fragmentManager.beginTransaction().replace(R.id.fcontent,myfragmenet).commit();
        menu.setChecked(true);
        setTitle(menu.getTitle());
        dr.closeDrawers();
    }
    private void SetUpDrawer(NavigationView navigater)
    {
        navigater.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
                selectDrawer(menuItem);
                return true;
            }
        });
    }

}

地图片段：

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        mView=inflater.inflate(R.layout.fragment_maps, container, false);
        return mView;
    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        MapFragment  mapFragment=(MapFragment) getChildFragmentManager().findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        MapsInitializer.initialize(getContext());
        mGoogleMap = googleMap;
        googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
        googleMap.addMarker(new MarkerOptions().position(new LatLng(36.7331,3.1567)).title("Hotel Hilton").snippet("Babez"));
        CameraPosition lib = CameraPosition.builder().target(new LatLng(36.7194,3.1405)).zoom(16).bearing(0).tilt(45).build();
        googleMap.moveCamera(CameraUpdateFactory.newCameraPosition(lib));
    }
   }

这是调试控制台显示的内容：

java.lang.NullPointerException：尝试调用虚拟方法空对象上的java.lang.Class java.lang.Object.getClass（） android.support.v4.app.BackStackRecord.doAddOp（BackStackRecord.java:396）上的参考在android.support.v4.app.BackStackRecord.replace（BackStackRecord.java:444）在android.support.v4.app.BackStackRecord.replace（BackStackRecord.java:434）在com.example.user.coursroyalschool.Main2Activity.selectDrawer（Main2Activity.java:81）在com.example.user.coursroyalschool.Main2Activity $ 1.onNavigationItemSelected（Main2Activity.java:91）在android.support.design.widget.NavigationView $ 1.onMenuItemSelected（NavigationView.java:170）在android.support.v7.view.menu.MenuBuilder.dispatchMenuItemSelected（MenuBuilder.java:840）

任何人都可以告诉我代码的问题在哪里吗？

如何在Android Studio中的片段中实现Google Maps？

0 个答案: