将引脚放在片段中的地图片段上

Question

我无法使用推荐的文档向地图添加标记，我没有错误，但地图上没有出现标记。

我尝试过以下方法：

    gmap = googleMap;
    gmap.setMinZoomPreference(12);
       LatLng ny = new LatLng(40.7143528, -74.0059731);
        gmap.moveCamera(CameraUpdateFactory.newLatLng(ny));

和

    gmap.addMarker(new MarkerOptions()
                .position(new LatLng(10, 10))
                .title("Hello world"));

这些都不起作用。

这是我的主要活动，

private static MapView mapView;
private GoogleMap gmap;
private static final String MAP_VIEW_BUNDLE_KEY = "MapViewBundleKey";

@Override
protected void onCreate(final Bundle savedInstanceState) 
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_home);

    session = new SessionHandler(getApplicationContext());
    final User user = session.getUserDetails();

    final View background = findViewById(R.id.home_background_view);
    final ViewPager viewPager = (ViewPager) findViewById(R.id.home_view_pager);
    MainPagerAdapter adapter = new MainPagerAdapter(getSupportFragmentManager());
    viewPager.setAdapter(adapter);

    final int colourGreen = ContextCompat.getColor(this, R.color.Green);
    final int colourPink = ContextCompat.getColor(this, R.color.Pink);
    final int colourBlue = ContextCompat.getColor(this, R.color.CafeSeaBlue);

    TabLayout tabLayout = (TabLayout) findViewById(R.id.am_tab_layout);
    tabLayout.setupWithViewPager(viewPager);


    loadLocations();


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



    viewPager.setCurrentItem(1);
        //mapView = findViewById(R.id.mapView);

    viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() 
        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) 

                //if on first screen
            if (position == 0)
            
                background.setBackgroundColor(colourBlue);
                    //background.setAlpha(1-positionOffset);
            

                //if on mid screen
            else if (position == 1) 
                background.setBackgroundColor(colourPink);
                    //background.setAlpha(positionOffset);
            

                //if on last screen
            else if (position == 2) 
                background.setBackgroundColor(colourGreen);
                    //background.setAlpha(1+positionOffset);
            
        

        @Override
        public void onPageSelected(int position) 
            if(position == 0)
            

            if(position == 2)

    //                        gmap.addMarker(new MarkerOptions()
    //                                .position(new LatLng(50, 50))
    //                                .title("Hello world"));

            

        

        @Override
        public void onPageScrollStateChanged(int state) 

        
    );



@Override
public void onConnected(@Nullable Bundle bundle) 



@Override
public void onConnectionSuspended(int i) 



@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) 



@Override
protected void onResume() 
    super.onResume();



@Override
protected void onStart() 
    super.onStart();




@Override
protected void onStop() 
    super.onStop();



@Override
public void onLocationChanged(Location location) 
    double currentLatitude = location.getLatitude();
    double currentLongitude = location.getLongitude();

    globalLat = location.getLatitude();
    globalLong = location.getLongitude();

    Log.d("Location","Longitude = "+currentLongitude);
    Log.d("Location","Latitude = "+currentLatitude);



    if(tv1 != null)
        tv1.setText(Double.toString(currentLatitude));


    if(tv2 != null)
        tv2.setText(Double.toString(currentLongitude));



@Override
public void onStatusChanged(String provider, int status, Bundle extras) 



@Override
public void onProviderEnabled(String provider) 



@Override
public void onProviderDisabled(String provider) 


    //progress bar
private void displayLoader() 
    pDialog = new ProgressDialog(HomeActivity.this);
    pDialog.setMessage("Loading.. Please wait...");
    pDialog.setIndeterminate(false);
    pDialog.setCancelable(false);
    pDialog.show();



@Override
public void onItemClick(View view, int position) 
    Toast.makeText(this, "You clicked " + adapter.getItem(position) + " on row number " + position, Toast.LENGTH_SHORT).show();



@Override
public void onSaveInstanceState(Bundle outState) 
    super.onSaveInstanceState(outState);

    Bundle mapViewBundle = outState.getBundle(MAP_VIEW_BUNDLE_KEY);
    if (mapViewBundle == null) 
        mapViewBundle = new Bundle();
        outState.putBundle(MAP_VIEW_BUNDLE_KEY, mapViewBundle);
    




@Override
protected void onPause() 
    super.onPause();

@Override
protected void onDestroy() 
    super.onDestroy();

@Override
public void onLowMemory() 
    super.onLowMemory();


@Override
public void onMapReady(GoogleMap map) 
    gmap.addMarker(new MarkerOptions()
        .position(new LatLng(10, 10))
        .title("Hello world"));

我的布局：


<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
tools:background="@color/CafeSeaBlue"
android:layout_height="match_parent"
android:layout_width="match_parent"
xmlns:tools="http://schemas.android.com/tools">

<View
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="80dp"
android:background="@drawable/card_background" />

<android.support.v7.widget.AppCompatTextView
android:id="@+id/latText1"
android:layout_width="match_parent"
android:layout_height="32dp"
android:layout_below="@+id/longText"
android:layout_marginTop="100dp"
android:layout_marginBottom="50dp"
android:background="@color/White"
android:text="Map Screen"
android:textAlignment="center"/>


<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"
android:layout_marginTop="150dp"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_marginBottom="40dp"
tools:context=".HomeActivity"
/>

</FrameLayout>

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

在该部分中取消注释它当前正在意外地崩溃它，说空对象引用

地图本身加载但我无法获得它的针脚。我尝试了很多方法，可能有相当多的不必要的代码。

地图显示在屏幕上，我会附上一张图片，但在我能够之前需要10分。我无法使用推荐的文档向地图添加标记，我没有错误，但地图上没有出现标记。