Navigation Drawer中Sign Out项无法跳转至Login页面求助

我希望实现导航抽屉（Navigation Drawer）中的“Sign Out”项点击后跳转至Login页面，代码无报错但功能失效，相关代码如下：

Homepage.java 代码 #

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    binding = ActivityHomepageBinding.inflate(getLayoutInflater());
    setContentView(binding.getRoot());

    setSupportActionBar(binding.appBarHomepage.toolbar);
    binding.appBarHomepage.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 = binding.drawerLayout;
    NavigationView navigationView = binding.navView;
    navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
            int id=menuItem.getItemId();
            if (id == R.id.nav_Sign_out){
                Intent intent = new Intent(Homepage.this, Login.class);
                startActivity(intent);
            }
            return true;
        }
    });
    
    mAppBarConfiguration = new AppBarConfiguration.Builder(R.id.nav_dashboard, R.id.nav_profile, R.id.nav_orders, R.id.nav_recent_orders,
            R.id.nav_pending_deliveries, R.id.nav_cancelled_orders, R.id.nav_settings)
            .setOpenableLayout(drawer)
            .build();
    NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_content_homepage);
    NavigationUI.setupActionBarWithNavController(this, navController, mAppBarConfiguration);
    NavigationUI.setupWithNavController(navigationView, navController);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.homepage, menu);
    return true;
}

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

Login.java 代码 #

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_login);

    textview = (TextView) findViewById(R.id.textViewSignUp);
    textview.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(Login.this,Register.class);
            startActivity(intent);
        }
    });

    button = (Button) findViewById(R.id.btnLogin);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent intent = new Intent(Login.this,Homepage.class);
            startActivity(intent);
        }
    });
}

activity_main_drawer.xml 代码 #

<group
    android:id="@+id/menu_top"
    android:checkableBehavior="none">
    <item
        android:id="@+id/nav_dashboard"
        android:icon="@drawable/ic_baseline_dashboard_24"
        android:title="@string/dashboard">
    </item>
    <item
        android:id="@+id/nav_profile"
        android:icon="@drawable/ic_baseline_person_24"
        android:title="@string/profile" >
    </item>
</group>
<item
    android:id="@+id/nav_orders"
    android:title="@string/orders" >
    <menu>
        <item
            android:id="@+id/nav_menu_orders"
            android:title="@string/Orders"
            android:icon="@drawable/ic_orders" />

        <item
            android:id="@+id/nav_recent_orders"
            android:title="@string/recent_orders"
            android:icon="@drawable/ic_recent" />
    </menu>
</item>
<item
    android:id="@+id/nav_deliveries"
    android:title="@string/deliveries" >
    <menu>
        <item
            android:id="@+id/nav_pending_deliveries"
            android:title="@string/pending_deliveries"
            android:icon="@drawable/ic_pending_deliveries"/>

        <item
            android:id="@+id/nav_recent_deliveries"
            android:title="@string/recent_deliveries"
            android:icon="@drawable/ic_recent" />
    </menu>
</item>
<item
    android:id="@+id/nav_cancelled_orders"
    android:icon="@drawable/ic_baseline_cancel_24"
    android:title="@string/cancelled_orders" >
</item>
<item
    android:id="@+id/nav_settings"
    android:icon="@drawable/ic_baseline_settings_24"
    android:title="@string/settings" >
</item>

<group
    android:id="@+id/nav_menu_bottom"
    android:checkableBehavior="none">
    <item
        android:id="@+id/nav_Sign_out"
        android:icon="@drawable/ic_sign_out"
        android:title="@string/sign_out">
    </item>
</group>

问题原因 #

你手动设置的OnNavigationItemSelectedListener被NavigationUI.setupWithNavController(navigationView, navController)覆盖了。这行代码会自动给NavigationView绑定导航控制器的默认点击监听器，直接替换掉你之前写的逻辑，导致Sign Out的点击事件根本不会触发。

解决方法 #

调整代码顺序，先让NavigationUI完成默认导航绑定，再设置自定义监听器，同时在监听器中区分处理Sign Out和其他默认导航项：

修改Homepage.java中的导航相关代码为：

DrawerLayout drawer = binding.drawerLayout;
NavigationView navigationView = binding.navView;

// 先初始化导航控制器并完成默认配置
mAppBarConfiguration = new AppBarConfiguration.Builder(R.id.nav_dashboard, R.id.nav_profile, R.id.nav_orders, R.id.nav_recent_orders,
        R.id.nav_pending_deliveries, R.id.nav_cancelled_orders, R.id.nav_settings)
        .setOpenableLayout(drawer)
        .build();
NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_content_homepage);
NavigationUI.setupActionBarWithNavController(this, navController, mAppBarConfiguration);
NavigationUI.setupWithNavController(navigationView, navController);

// 重新设置自定义监听器，处理Sign Out逻辑
navigationView.setNavigationItemSelectedListener(item -> {
    int id = item.getItemId();
    if (id == R.id.nav_Sign_out) {
        // 跳转Login页面，同时清除栈避免返回主页
        Intent intent = new Intent(Homepage.this, Login.class);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
        startActivity(intent);
        finish(); // 关闭当前Homepage
        drawer.closeDrawer(GravityCompat.START); // 关闭导航抽屉
        return true;
    }
    // 其他导航项交给NavigationUI处理
    return NavigationUI.onNavDestinationSelected(item, navController)
            || super.onOptionsItemSelected(item);
});

额外优化 #

• 添加intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK)可以清除当前活动栈，用户从Login页返回时不会回到Homepage，符合退出登录的逻辑。
• 调用drawer.closeDrawer(GravityCompat.START)在点击后关闭导航抽屉，提升用户体验。

内容的提问来源于stack exchange，提问作者NoobieMobileDev