java - 将图钉放置在 fragment 中的 map fragment 上

Question

我无法使用推荐的文档向我的 map 添加标记，我没有错误，但标记没有出现在 map 上。

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 Activity ，

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"));
}
}

还有我的布局:

<?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);

在当前所在的部分中取消注释它会意外崩溃，说空对象引用

map 本身会加载，但我无法在上面找到图钉。我尝试了很多方法，可能有不少不必要的代码。

map 显示在屏幕上，我会附加一张图像，但我需要 10 点才能添加。我无法使用推荐的文档向 map 添加标记，没有错误，但标记没有出现在 map 上。

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 Activity ，

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"));
}
}

还有我的布局:

<?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);

在当前所在的部分中取消注释它会意外崩溃，说空对象引用

map 本身会加载，但我无法在上面找到图钉。我尝试了很多方法，可能有不少不必要的代码。

我会在此处附上显示和可交互 map 的图像，但我没有 10 分。 /image/xm0nZ.png

Answer 1

您似乎将 map 聚焦在纽约市地区，但将标记固定在尼日利亚中部。您确定标记没有添加成功吗？尝试将标记设置在 map 焦点位置附近。