使用 Fragment 和 FragmentActivity 更改导航抽屉中的活动

Question

我是一名新手程序员，我正在尝试学习一些 Android 知识。 我遵循一些教程，现在我有一个导航抽屉应用程序。到目前为止，我已经使用菜单中的按钮管理了布局的更改。现在我想创建一个地图定位器，我关注了这个Tutorial。现在我想单击一个按钮，将我带到这个新的 Activity，我可以在其中跟踪位置。

我的代码是： GalleryFragment.Java

package com.example.frangela.ui.gallery;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentActivity;
import androidx.fragment.app.FragmentManager;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModelProvider;

import com.example.frangela.R;
import com.example.frangela.Spesa;
import com.example.frangela.databinding.FragmentGalleryBinding;
import com.example.frangela.ui.deter.DeterminaFrag;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;

public class GalleryFragment extends Fragment {
    private GalleryViewModel galleryViewModel;
    private FragmentGalleryBinding binding;

    public View onCreateView(@NonNull LayoutInflater inflater,
                             ViewGroup container, Bundle savedInstanceState) {
        galleryViewModel =
                new ViewModelProvider(this).get(GalleryViewModel.class);

        binding = FragmentGalleryBinding.inflate(inflater, container, false);
        View root = binding.getRoot();
        EditText ET = binding.EditProva;
        Button btn = binding.buttonProva;

        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                FragmentActivity fragment = new DeterminaFrag();
                FragmentManager fragmentManager = fragment.getSupportFragmentManager();
                fragmentManager.beginTransaction().replace(R.id.nav_host_fragment_content_main, fragment);

            }
        });

        galleryViewModel.getText().observe(getViewLifecycleOwner(), new Observer<String>() {
            @Override
            public void onChanged(@Nullable String s) {
                //textView.setText(s);
            }
        });
        return root;
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        binding = null;
    }
}

DeterminaFrag.java

package com.example.frangela.ui.deter;
import androidx.annotation.NonNull;
import androidx.core.app.ActivityCompat;
import androidx.fragment.app.FragmentActivity;

import android.Manifest;
import android.content.pm.PackageManager;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;

import com.example.frangela.R;
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;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;

import java.util.Arrays;

public class DeterminaFrag extends FragmentActivity implements OnMapReadyCallback {

    private GoogleMap mMap;
    private DatabaseReference databaseReference;

    private LocationListener locationListener;
    private LocationManager locationManager;
    private final long MIN_TIME = 1000;
    private final long MIN_DIST = 5;

    private EditText editTextLatitude;
    private EditText editTextLongitude;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);

        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION}, PackageManager.PERMISSION_GRANTED);

        editTextLatitude = findViewById(R.id.editText);
        editTextLongitude = findViewById(R.id.editText2);

        databaseReference = FirebaseDatabase.getInstance().getReference("Location");
        databaseReference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                try {
                    String databaseLatitudeString = dataSnapshot.child("latitude").getValue().toString().substring(1, dataSnapshot.child("latitude").getValue().toString().length()-1);
                    String databaseLongitudedeString = dataSnapshot.child("longitude").getValue().toString().substring(1, dataSnapshot.child("longitude").getValue().toString().length()-1);

                    String[] stringLat = databaseLatitudeString.split(", ");
                    Arrays.sort(stringLat);
                    String latitude = stringLat[stringLat.length-1].split("=")[1];

                    String[] stringLong = databaseLongitudedeString.split(", ");
                    Arrays.sort(stringLong);
                    String longitude = stringLong[stringLong.length-1].split("=")[1];


                    LatLng latLng = new LatLng(Double.parseDouble(latitude), Double.parseDouble(longitude));

                    mMap.addMarker(new MarkerOptions().position(latLng).title(latitude + " , " + longitude));
                    mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));


                }
                catch (Exception e){
                    e.printStackTrace();
                }


            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });
    }


    /**
     * 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) {
        mMap = googleMap;

//        // Add a marker in Sydney and move the camera
//        LatLng sydney = new LatLng(-34, 151);
//        mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
//        mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));

        locationListener = new LocationListener() {
            @Override
            public void onLocationChanged(Location location) {
                try {
                    editTextLatitude.setText(Double.toString(location.getLatitude()));
                    editTextLongitude.setText(Double.toString(location.getLongitude()));
                } catch (Exception e) {
                    e.printStackTrace();
                }

            }

            @Override
            public void onStatusChanged(String s, int i, Bundle bundle) {

            }

            @Override
            public void onProviderEnabled(String s) {

            }

            @Override
            public void onProviderDisabled(String s) {

            }
        };

        locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

        if (checkSelfPermission(Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            // TODO: Consider calling
            //    Activity#requestPermissions
            // here to request the missing permissions, and then overriding
            //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
            //                                          int[] grantResults)
            // to handle the case where the user grants the permission. See the documentation
            // for Activity#requestPermissions for more details.
            return;
        }

        try {
            locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, MIN_TIME, MIN_DIST, locationListener);
            locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, MIN_TIME, MIN_DIST, locationListener);
        }
        catch (Exception e){
            e.printStackTrace();
        }
    }

    public void updateButtonOnclick(View view){

        databaseReference.child("latitude").push().setValue(editTextLatitude.getText().toString());
        databaseReference.child("longitude").push().setValue(editTextLongitude.getText().toString());

    }
}

fragment_Gallery.xml

<?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=".ui.gallery.GalleryFragment">

    <EditText
        android:id="@+id/EditProva"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="100sp"
        android:foregroundGravity="center_horizontal"
        android:gravity="center_horizontal"
        android:padding="40sp"
        android:text="Inserire qualcosa di prova"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />
    <Button
        android:id="@+id/button_prova"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Prova"
        app:layout_constraintTop_toBottomOf="@+id/EditProva"
        tools:layout_editor_absoluteX="150dp" />
</androidx.constraintlayout.widget.ConstraintLayout>

activity_maps.xml

<?xml version="1.0" encoding="utf-8"?>
<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=".ui.deter.DeterminaFrag">


    <fragment
        android:id="@+id/map"
        android:name="com.google.android.gms.maps.SupportMapFragment"
        android:layout_width="match_parent"
        android:layout_height="550dp"
        tools:context=".MapsActivity"
        tools:layout="@android:layout/simple_spinner_dropdown_item" />

    <EditText
        android:id="@+id/editText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="30dp"
        android:layout_marginTop="550dp"
        android:ems="10"
        android:hint="Latitudine"
        android:inputType="textPersonName"
        android:autofillHints="" />

    <EditText
        android:id="@+id/editText2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="220dp"
        android:layout_marginTop="550dp"
        android:ems="10"
        android:hint="Longitudine"
        android:inputType="textPersonName"
        android:autofillHints="" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="150dp"
        android:layout_marginTop="600dp"
        android:onClick="updateButtonOnclick"
        android:text="Aggiorna" />

</FrameLayout>

content_main.xml

<?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"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:showIn="@layout/app_bar_main">

    <fragment
        android:id="@+id/nav_host_fragment_content_main"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:defaultNavHost="true"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:navGraph="@navigation/mobile_navigation" />
</androidx.constraintlayout.widget.ConstraintLayout>

我认为问题出在这段代码中（实际上它甚至没有编译）

        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                FragmentActivity fragment = new DeterminaFrag();
                FragmentManager fragmentManager = fragment.getSupportFragmentManager();
                fragmentManager.beginTransaction().replace(R.id.nav_host_fragment_content_main, fragment);

            }
        });

不知道能不能把这个Fragment改成FragmentActivity。我一直在寻找类似的问题，但我没有找到任何东西。 感谢您的帮助

Answer 1

我想你忘记提交事务了，像这样

btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            FragmentActivity fragment = new DeterminaFrag();
            FragmentManager fragmentManager = fragment.getSupportFragmentManager();
            fragmentManager.beginTransaction().replace(R.id.nav_host_fragment_content_main, fragment);
            fragmentManager.commit();

        }
    });

希望对你的问题有所帮助