材料组件，从版本1.4开始。如文档中所述，你可以使用MaterialToolbar。

只需在MaterialToolbar上添加属性app:titleCentered和/或app:subtitleCentered属性为true即可。

喜欢的东西:

    <com.google.android.material.appbar.MaterialToolbar
        android:id="@+id/topAppBar"
        app:titleCentered="true"
        ... />

使用Material3包撰写，你可以简单地使用CenterAlignedTopAppBar:

CenterAlignedTopAppBar(
    title = { Text("Centered TopAppBar") },
    navigationIcon = {
        IconButton(onClick = { /* doSomething() */ }) {
            Icon(
                imageVector = Icons.Filled.Menu,
                contentDescription = "Localized description"
            )
        }
    }
)

如果您正在使用Compose和Material2包，没有内置组件，但您可以自定义TopAppBar内内容的布局，如本文所述。

    public class TestActivity extends AppCompatActivity {
    private Toolbar toolbar;

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

        toolbar = (Toolbar) findViewById(R.id.tool_bar); // Attaching the layout to the toolbar object
        setSupportActionBar(toolbar);

        customizeToolbar(toolbar);
    }

    public void customizeToolbar(Toolbar toolbar){
        // Save current title and subtitle
        final CharSequence originalTitle = toolbar.getTitle();
        final CharSequence originalSubtitle = toolbar.getSubtitle();

        // Temporarily modify title and subtitle to help detecting each
        toolbar.setTitle("title");
        toolbar.setSubtitle("subtitle");

        for(int i = 0; i < toolbar.getChildCount(); i++){
            View view = toolbar.getChildAt(i);

            if(view instanceof TextView){
                TextView textView = (TextView) view;


                if(textView.getText().equals("title")){
                    // Customize title's TextView
                    Toolbar.LayoutParams params = new Toolbar.LayoutParams(Toolbar.LayoutParams.WRAP_CONTENT, Toolbar.LayoutParams.MATCH_PARENT);
                    params.gravity = Gravity.CENTER_HORIZONTAL;
                    textView.setLayoutParams(params);

                    // Apply custom font using the Calligraphy library
                    Typeface typeface = TypefaceUtils.load(getAssets(), "fonts/myfont-1.otf");
                    textView.setTypeface(typeface);

                } else if(textView.getText().equals("subtitle")){
                    // Customize subtitle's TextView
                    Toolbar.LayoutParams params = new Toolbar.LayoutParams(Toolbar.LayoutParams.WRAP_CONTENT, Toolbar.LayoutParams.MATCH_PARENT);
                    params.gravity = Gravity.CENTER_HORIZONTAL;
                    textView.setLayoutParams(params);

                    // Apply custom font using the Calligraphy library
                    Typeface typeface = TypefaceUtils.load(getAssets(), "fonts/myfont-2.otf");
                    textView.setTypeface(typeface);
                }
            }
        }

        // Restore title and subtitle
        toolbar.setTitle(originalTitle);
        toolbar.setSubtitle(originalSubtitle);
    }
}

现在使用材质设计3，我们可以在中间对齐标题，而不需要做额外的工作，也不需要在工具栏中添加文本视图

在构建中添加了以下依赖项。gradle文件

implementation 'com.google.android.material:material:1.6.1'

为了使标题在中心对齐，我们需要正确地使用下面的内容

 app:titleCentered="true"

为了在中心对齐字幕，我们需要使用下面的属性

app:subtitleCentered="true"

示例代码

<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout
    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">

  <com.google.android.material.appbar.AppBarLayout
      android:layout_width="match_parent"
      android:layout_height="wrap_content">

    <com.google.android.material.appbar.MaterialToolbar
        android:id="@+id/topAppBar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        app:title="AskNilesh"
        app:subtitle="Nilesh"
        app:subtitleCentered="true"
        app:menu="@menu/top_app_bar"
        app:titleCentered="true"
        app:navigationIcon="@drawable/ic_android_black_24dp" />

  </com.google.android.material.appbar.AppBarLayout>

  <androidx.core.widget.NestedScrollView
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      app:layout_behavior="@string/appbar_scrolling_view_behavior">


  </androidx.core.widget.NestedScrollView>

</androidx.coordinatorlayout.widget.CoordinatorLayout>

输出

对于自定义字体在工具栏，你可以覆盖textView字体的风格，然后每个textView在你的应用程序也工具栏标题字体自动改变 我在android studio 3.1.3中进行了测试

在风格上这样做:

<style name="defaultTextViewStyle" parent="android:Widget.TextView">
        <item name="android:fontFamily">@font/your_custom_font</item>
</style>

然后在你的主题中使用这个:

<item name="android:textViewStyle">@style/defaultTextViewStyle</item>

  @Composable
    fun topAppBar() {
        CenterAlignedTopAppBar(
            title = {
                Text(
                    "Top App Bar"
                )
            },
            navigationIcon = {
                IconButton(onClick = { /*TODO*/ }) {
                    Icon(
                        imageVector = Icons.Default.ArrowBack,
                        contentDescription = "Back"
                    )
                }
            },
            actions = {
                IconButton(onClick = { /*TODO*/ }) {
                    Icon(
                        imageVector = Icons.Default.MoreVert,
                        contentDescription = "More",
                    )
                }
            },
            colors = TopAppBarDefaults.smallTopAppBarColors(
                containerColor = MaterialTheme.colorScheme.secondaryContainer
            )
        )
    }
}

我也遇到了同样的问题，通过在MainActivity中这样做来解决

Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
TextView mTitle = (TextView) toolbar.findViewById(R.id.toolbar_title);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayShowTitleEnabled(false);

碎片化

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    if (view == null) {
        // Inflate the layout for this fragment
        view = inflater.inflate(R.layout.fragment_example, container, false);
        init();
    }
    getActivity().setTitle("Choose Fragment");
    return view;
}

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    inflater.inflate(R.menu.example_menu, menu);
}