要在工具栏中使用自定义标题，您可以添加一个自定义标题，如:

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    android:background="?attr/colorPrimary"
    android:elevation="5dp"
    app:contentInsetLeft="0dp"
    app:contentInsetStart="0dp"
    app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
    app:theme="@style/ThemeOverlay.AppCompat.Dark">


        <LinearLayout
            android:id="@+id/lnrTitle"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center_horizontal"
            android:orientation="vertical">

            <TextView
                android:id="@+id/txvHeader"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center_horizontal|center"
                android:gravity="center"
                android:ellipsize="end"
                android:maxLines="1"
                android:text="Header"
                android:textColor="@color/white"
                android:textSize="18sp" />


        </LinearLayout>


</android.support.v7.widget.Toolbar>

Java代码:

Toolbar toolbar = findViewById(R.id.toolbar);

setSupportActionBar(toolbar);

if (getSupportActionBar() == null)
    return;

getSupportActionBar().setTitle("Title");

getSupportActionBar().setDisplayHomeAsUpEnabled(true);

Material Components 1.4.0-alpha02中的MaterialToolbar现在能够通过设置titleCentered属性为true来居中工具栏的标题:

<com.google.android.material.appbar.AppBarLayout
    android:id="@+id/appBarLayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <com.google.android.material.appbar.MaterialToolbar
        android:id="@+id/topAppBar"
        style="@style/Widget.MaterialComponents.Toolbar.Primary"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        app:titleCentered="true" />

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

我用这个问题的解决方案:

 public static void applyFontForToolbarTitle(Activity a){
        Toolbar toolbar = (Toolbar) a.findViewById(R.id.app_bar);
        for(int i = 0; i < toolbar.getChildCount(); i++){
            View view = toolbar.getChildAt(i);
            if(view instanceof TextView){
                TextView tv = (TextView) view;
                if(tv.getText().equals(a.getTitle())){
                    tv.setTypeface(getRuneTypefaceBold(a));
                    break;
                }
            }
        }
    }

对于重心，我认为有必要将布局参数水平更改为match_parent，然后:

tv.setGravity(Gravity.CENTER);

我找到了另一种方法来添加自定义工具栏，而不需要任何额外的Java/Kotlin代码。

First: create a XML with your custom toolbar layout with AppBarLayout as the parent: <?xml version="1.0" encoding="utf-8"?> <android.support.design.widget.AppBarLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="wrap_content" android:theme="@style/AppTheme.AppBarOverlay"> <android.support.v7.widget.Toolbar android:id="@+id/toolbar" android:layout_width="match_parent" android:layout_height="?attr/actionBarSize" android:background="?attr/colorPrimary" app:popupTheme="@style/AppTheme.PopupOverlay"> <ImageView android:layout_width="80dp" android:layout_height="wrap_content" android:layout_gravity="right" android:layout_marginEnd="@dimen/magin_default" android:src="@drawable/logo" /> </android.support.v7.widget.Toolbar> Second: Include the toolbar in your layout: <?xml version="1.0" encoding="utf-8"?> <android.support.constraint.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" android:background="@color/blue" tools:context=".app.MainAcitivity" tools:layout_editor_absoluteY="81dp"> <include layout="@layout/toolbar_inicio" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" /> <!-- Put your layout here --> </android.support.constraint.ConstraintLayout>

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。

我使用这个解决方案:

static void centerToolbarTitle(@NonNull final Toolbar toolbar) {
    final CharSequence title = toolbar.getTitle();
    final ArrayList<View> outViews = new ArrayList<>(1);
    toolbar.findViewsWithText(outViews, title, View.FIND_VIEWS_WITH_TEXT);
    if (!outViews.isEmpty()) {
        final TextView titleView = (TextView) outViews.get(0);
        titleView.setGravity(Gravity.CENTER);
        final Toolbar.LayoutParams layoutParams = (Toolbar.LayoutParams) titleView.getLayoutParams();
        layoutParams.width = ViewGroup.LayoutParams.MATCH_PARENT;
        toolbar.requestLayout();
        //also you can use titleView for changing font: titleView.setTypeface(Typeface);
    }
}