是否可以使用 AndroidX 导航将片段中的操作栏标题居中？

Question

目前，我正在使用 Android 中的导航组件，操作栏标题显示在左侧。 但是，我有点希望它集中以使事情更整洁，有什么办法可以让 go 这样做吗？

左侧显示的操作栏标题的图像

活动代码：

public class General extends AppCompatActivity {
    private BottomNavigationView bottomNavigationView;
    private NavController navController;
    private AppBarConfiguration appBarConfiguration;

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

        bottomNavigationView = findViewById(R.id.bottomNavigationView);
        navController = Navigation.findNavController(this,  R.id.fragment);

        appBarConfiguration = new AppBarConfiguration.Builder(R.id.addFragment, R.id.homeFragment).build();

        NavigationUI.setupWithNavController(bottomNavigationView, navController);
        NavigationUI.setupActionBarWithNavController(this, navController, appBarConfiguration);
    }
}

活动的 XML 代码

<?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=".General">

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bottomNavigationView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:menu="@menu/bottom_navigation_menu">

    </com.google.android.material.bottomnavigation.BottomNavigationView>

    <fragment
        android:id="@+id/fragment"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:defaultNavHost="true"
        app:layout_constraintBottom_toTopOf="@+id/bottomNavigationView"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:navGraph="@navigation/the_navigation" />

</androidx.constraintlayout.widget.ConstraintLayout>

片段 XML 代码：

<?xml version="1.0" encoding="utf-8"?>
<navigation 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:id="@+id/the_navigation"
    app:startDestination="@id/homeFragment">

    <fragment
        android:id="@+id/homeFragment"
        android:name="com.test.HomeFragment"
        android:label="Home"
        tools:layout="@layout/home_fragment" />
    <fragment
        android:id="@+id/addFragment"
        android:name="com.test.AddFragment"
        android:label="Add"
        tools:layout="@layout/add_fragment" />
</navigation>

Answer 1

经过一番搜索， 这似乎成功了。 我所要做的就是将它添加到我的活动代码中。

Answer 2

由于片段是 Parent Activity 的子项，因此我们可以根据需要在 Parent Activity 上集中或自定义标题。 这是一个示例，如何在不对所有视图小部件进行迭代的情况下将标题居中...

override fun onCreate(savedInstanceState: Bundle?) {
        setTheme(R.style.AppTheme);
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        navView = findViewById(R.id.nav_view)
        navController = findNavController(R.id.nav_host_fragment)

        // Passing each menu ID as a set of Ids because each
        // menu should be considered as top level destinations.
        val appBarConfiguration = AppBarConfiguration(
            setOf(
                R.id.navigation_home, R.id.navigation_settings, R.id.navigation_info
            )
        )
        setupActionBarWithNavController(navController, appBarConfiguration)
        navView.setupWithNavController(navController)

        // Detect on where fragment we are, and custom the title from here
        navController

            .addOnDestinationChangedListener { nc: NavController, nd: NavDestination, args: Bundle? ->
                when(nd.id){
                    R.id.navigation_home -> {
                        supportActionBar?.displayOptions = ActionBar.DISPLAY_SHOW_CUSTOM
                        supportActionBar?.setCustomView(R.layout.title_home_action_bar_layout)
                       
                    }
                    R.id.navigation_settings -> {
                        supportActionBar?.displayOptions = ActionBar.DISPLAY_SHOW_CUSTOM
                        supportActionBar?.setCustomView(R.layout.title_settings_action_bar_layout)
                      
                    }
                    R.id.navigation_info -> {
                        supportActionBar?.displayOptions = ActionBar.DISPLAY_SHOW_CUSTOM
                        supportActionBar?.setCustomView(R.layout.title_info_action_bar_layout)
                        
                    }
                }
            }

    }

对于自定义居中标题：title_settings_action_bar_layout.xml

    <?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:orientation="vertical">
    
        <TextView
            android:id="@+id/tvTitle"
            style="@style/TextAppearance.AppCompat.Widget.ActionBar.Title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:text="Settings Baby Watcher"
            android:textColor="#FFFFFF" />
    
    </LinearLayout>