如何在android studio的新导航抽屉中实现退出功能？

Question

我想在我的项目中实现注销方法。我观看了所有 youtube 教程，但似乎导航抽屉是更新版本。而且我对如何将那些退出编码实现到我的编码中一无所知。

最新版本的导航抽屉已经内置在 ui 包文件夹中。所以我不太确定如何实现这些教程代码，因为大多数教程代码都有这个代码。 下面是教程代码，我不知道如何在我的 home.java 代码中实现注销方法。谢谢你

 @SuppressWarnings("StatementWithEmptyBody")
        @Override
        public boolean onNavigationItemSelected(MenuItem item) {
            // Handle navigation view item clicks here.
            int id = item.getItemId();

            if (id == R.id.nav_home) {

                getSupportActionBar().setTitle("Home");
                getSupportFragmentManager().beginTransaction().replace(R.id.container,new HomeFragment()).commit();

            } else if (id == R.id.nav_profile) {

                getSupportActionBar().setTitle("Profile");
                getSupportFragmentManager().beginTransaction().replace(R.id.container,new ProfileFragment()).commit();

            } else if (id == R.id.nav_settings) {

                getSupportActionBar().setTitle("Settings");
                getSupportFragmentManager().beginTransaction().replace(R.id.container,new SettingsFragment()).commit();


            }
            else if (id == R.id.nav_signout) {

                FirebaseAuth.getInstance().signOut();
                Intent loginActivity = new Intent(getApplicationContext(),LoginActivity.class);
                startActivity(loginActivity);
                finish();


            }

            DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
            drawer.closeDrawer(GravityCompat.START);
            return true;
        }

这是我的 home.java 代码

package com.example.guru;
import android.os.Bundle;

import com.google.android.material.floatingactionbutton.FloatingActionButton;
import com.google.android.material.snackbar.Snackbar;

import android.view.View;

import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.navigation.ui.AppBarConfiguration;
import androidx.navigation.ui.NavigationUI;

import com.google.android.material.navigation.NavigationView;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;

import androidx.drawerlayout.widget.DrawerLayout;

import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;

import android.view.Menu;
import android.widget.TextView;

public class Home extends AppCompatActivity {

    FirebaseAuth firebaseAuth;
    FirebaseUser currentUser;
    DatabaseReference databaseReference;

    private AppBarConfiguration mAppBarConfiguration;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home);
        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);


        //ini
        firebaseAuth = FirebaseAuth.getInstance();
        currentUser = firebaseAuth.getCurrentUser();
        databaseReference = FirebaseDatabase.getInstance().getReference("Customer");


        FloatingActionButton fab = findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        DrawerLayout drawer = findViewById(R.id.drawer_layout);

        NavigationView navigationView = findViewById(R.id.nav_view);
        // Passing each menu ID as a set of Ids because each
        // menu should be considered as top level destinations.
        mAppBarConfiguration = new AppBarConfiguration.Builder(
                R.id.nav_home, R.id.nav_profile, R.id.nav_orders,R.id.nav_logout)
                .setDrawerLayout(drawer)
                .build();



        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
        NavigationUI.setupActionBarWithNavController(this, navController, mAppBarConfiguration);
        NavigationUI.setupWithNavController(navigationView, navController);



        updateNavHeader();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.home, menu);
        return true;
    }

    @Override
    public boolean onSupportNavigateUp() {
        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
        return NavigationUI.navigateUp(navController, mAppBarConfiguration)
                || super.onSupportNavigateUp();
    }

    public void updateNavHeader() {
        NavigationView navigationView = findViewById(R.id.nav_view);
        View headerView= navigationView.getHeaderView(0);
        TextView navName= headerView.findViewById(R.id.txtName);
        TextView navEmail=headerView.findViewById(R.id.txtEmail);

        navName.setText(currentUser.getDisplayName());
        navEmail.setText(currentUser.getEmail());

    }
}

注销片段

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

import androidx.annotation.Nullable;
import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModelProviders;

import com.example.guru.R;

public class LogoutFragment extends Fragment {

    private LogoutViewModel logoutViewModel;

    public View onCreateView(@NonNull LayoutInflater inflater,
                             ViewGroup container, Bundle savedInstanceState) {
        logoutViewModel =
                ViewModelProviders.of(this).get(LogoutViewModel.class);
        View root = inflater.inflate(R.layout.fragment_logout, container, false);
        final TextView textView = root.findViewById(R.id.text_logout);

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

这是我的 LogoutViewModel

package com.example.guru.ui.Logout;

import androidx.lifecycle.LiveData;
import androidx.lifecycle.MutableLiveData;
import androidx.lifecycle.ViewModel;

public class LogoutViewModel extends ViewModel {

    private MutableLiveData<String> mText;

    public LogoutViewModel() {
        mText = new MutableLiveData<>();
        mText.setValue("logout");
    }

    public LiveData<String> getText() {
        return mText;
    }
}

Answer 1

感觉应该有一个内置的解决方案，但到目前为止我已经这样解决了。 我只是在该菜单选项上添加了一个点击监听器，在我的例子中是我的注销按钮：

在 Java 中 -->

NavigationView navigationView = findViewById(R.id.nav_view);
navigationView.getMenu().findItem(R.id.logout).setOnMenuItemClickListener(menuItem -> {
    logout();
    return true;
});

在 Kotlin 中 -->

navView.getMenu().findItem(R.id.nav_logout).setOnMenuItemClickListener({ menuItem ->
                logoutDialog()
                true
            })

Answer 2

我的导航菜单代码

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    tools:showIn="navigation_view">
    <item
        android:id="@+id/nav_share"
        android:icon="@drawable/ic_menu_share"
        android:title="@string/menu_share" />
    <item
        android:id="@+id/logout"
        android:icon="@drawable/logout"
        android:title="Logout" />
    <item
        android:id="@+id/login"
        android:icon="@drawable/logout"
        android:title="Login" />
</menu>

onResume 方法中的代码，这将根据用户的身份验证状态隐藏退出或登录按钮

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

        if (auth.getCurrentUser() == null) {
            navigationView.getMenu().findItem(R.id.logout).setVisible(false);
            navigationView.getMenu().findItem(R.id.login).setVisible(true);
            // perform action when user is not logged in
        } else {
            navigationView.getMenu().findItem(R.id.logout).setVisible(true);
            navigationView.getMenu().findItem(R.id.login).setVisible(false);
            // perform action when user is already logged in
        }

    }

在此处处理导航视图项的点击。

@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
    int id = item.getItemId();
    if (id == R.id.logout) {
        auth.signOut();
        onResume();
    } else if (id == R.id.login) {
        //handle event login button pressed 
        startActivity(new Intent(MainActivity.this, LoginActivity.class));
    }

    DrawerLayout drawer = findViewById(R.id.drawer_layout);
    drawer.closeDrawer(GravityCompat.START);
    return true;
}

希望对你有帮助

Answer 3

我找到了两种解决方案来处理它。

1.如果您在导航图中注册了您的片段而不是

 navController.addOnDestinationChangedListener(new NavController.OnDestinationChangedListener() {
            @Override
            public void onDestinationChanged(@NonNull NavController controller, @NonNull NavDestination destination, @Nullable Bundle arguments) {
                if (destination.getId() == R.id.logout){
                    logout();
                }
            }
        });

2。如果您在导航图中没有注册片段，而您只想处理抽屉菜单上的点击事件。

mNavigationView.getMenu().findItem(R.id.nav_logout).setOnMenuItemClickListener(menuItem -> {
            AppUtils.showLongToast("this works", getApplicationContext());
            return true;
        });