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>

我们没有直接访问工具栏标题TextView，所以我们使用反射来访问它。

  private TextView getActionBarTextView() {
    TextView titleTextView = null;

    try {
        Field f = mToolBar.getClass().getDeclaredField("mTitleTextView");
        f.setAccessible(true);
        titleTextView = (TextView) f.get(mToolBar);
    } catch (NoSuchFieldException e) {
    } catch (IllegalAccessException e) {
    }
    return titleTextView;
}

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);

您可以在xml文件中插入这段代码

 <androidx.appcompat.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/colorPrimaryDark"
    android:elevation="4dp"
    android:theme="@style/ThemeOverlay.AppCompat.ActionBar">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Toolbar Title"
        android:textColor="#000000"
        android:textSize="20dp"
        android:id="@+id/toolbar_title" />

</androidx.appcompat.widget.Toolbar>

我花了几天时间寻找一个通用的解决方案。我的工具栏与android菜单和导航图标。

首先，您需要创建自定义工具栏类。这个类必须计算标题居中的位置(填充):

    class CenteredToolbar @JvmOverloads constructor(context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0)
    : Toolbar(context, attrs, defStyleAttr) {

    init {
        addOnLayoutChangeListener(object : View.OnLayoutChangeListener {
            override fun onLayoutChange(v: View?, left: Int, top: Int, right: Int, bottom: Int, oldLeft: Int, oldTop: Int, oldRight: Int, oldBottom: Int) {
                val titleTextView = findViewById<TextView>(R.id.centerTitle)

                val x = titleTextView.x.toInt()
                val x2 = x + titleTextView.width

                val fullWidth = width
                val fullCenter = fullWidth / 2

                val offsetLeft = Math.abs(fullCenter - x)
                val offsetRight = Math.abs(x2 - fullCenter)
                val differOffset = Math.abs(offsetLeft - offsetRight)

                if (offsetLeft > offsetRight) {
                    titleTextView.setPadding(differOffset, 0, 0, 0)
                } else if (offsetRight > offsetLeft) {
                    titleTextView.setPadding(0, 0, differOffset, 0)
                }

                removeOnLayoutChangeListener(this)
            }
        })
    }

    override fun setTitle(resId: Int) = getTitleView().setText(resId)

    override fun setTitle(title: CharSequence?) = getTitleView().setText(title)

    fun getTitleView(): TextView = findViewById(R.id.centerTitle)

}

其次，你需要创建布局工具栏:

<CenteredToolbar xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/toolbar">

    <TextView
        android:id="@+id/centerTitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

</CenteredToolbar>

这是所有

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);
}