如何在地图片段中显示地图

Question

导航活动

package com.example.sanad;
import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.navigation.ui.NavigationUI;
import com.google.android.material.bottomnavigation.BottomNavigationView;
public class navigation extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_navigation);
BottomNavigationView bottomNavigationView = findViewById(R.id.bottomView);
NavController navController = Navigation.findNavController(this,R.id.nav_host_fragment);
NavigationUI.setupWithNavController(bottomNavigationView,navController);

// Fragment fragment = new MapsFragment();
//  getSupportFragmentManager().beginTransaction().replace(R.id.map,fragment).commit();
}
}

映射片段

package com.example.sanad;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
public class MapsFragment extends Fragment {
private OnMapReadyCallback callback = new OnMapReadyCallback() {
/**
* Manipulates the map once available.
* This callback is triggered when the map is ready to be used.
* This is where we can add markers or lines, add listeners or move the camera.
* In this case, we just add a marker near Sydney, Australia.
* If Google Play services is not installed on the device, the user will be prompted to
* install it inside the SupportMapFragment. This method will only be triggered once the
* user has installed Google Play services and returned to the app.
*/
@Override
public void onMapReady(GoogleMap googleMap) {
LatLng sydney = new LatLng(-34, 151);
googleMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
googleMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
}
};
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater,
@Nullable ViewGroup container,
@Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_maps, container, false);

}
/** -------------------------------------------------------------*/
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
SupportMapFragment mapFragment =
(SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.map);
if (mapFragment != null) {
mapFragment.getMapAsync(callback);
}
}
}
/** ----------------------------------------------------------*/

碎片地图布局

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/map_view"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MapsFragment"
tools:ignore="DuplicateIds">
<com.google.android.gms.maps.MapView
android:id="@+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent">
</com.google.android.gms.maps.MapView>
</RelativeLayout>

导航布局

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".navigation">
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="@+id/bottomView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:menu="@menu/menu_bottom_nav"
android:background="@color/white_200"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
<fragment
android:id="@+id/nav_host_fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:defaultNavHost="true"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:navGraph="@navigation/navigation_graphe" />
</androidx.constraintlayout.widget.ConstraintLayout>

你好，我是android开发的新手，我正在尝试制作一个底部导航栏，其中包含3个项目(声明、概要文件和地图(我已经成功地显示了登录后的导航活动，包括3个片段的map声明和profil，但对于map片段，我无法显示map。任何帮助或提示都将不胜感激，谢谢。

Answer 1

我添加了以下代码：

<fragment
android:layout_width="match_parent"
android:layout_height="match_parent"
android:name="com.google.android.gms.maps.SupportMapFragment"
tools:context=".MapsActivity">

</fragment>

而不是

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

现在地图上显示