Is there an official API for centered title on Toolbar like on popular Android apps, in the new material design?

半城伤御伤魂 提交于 2019-11-30 12:51:21

TL;DR: No, there's currently no official way to center the title on a toolbar.


I don't think there is an official way to do it, at least not yet. But I know that the Flutter framework supports it and it's pretty straight forward: you simply need to pass centerTitle: true to the appbar constructor, as described in this answer. And there's a good chance that the apps you've mentioned in your question were built with Flutter, since both are from Google.

I think the closest workaround to your expected layout is having the TextView on top of the Toolbar, as shown here:

<android.support.design.widget.AppBarLayout
    android:id="@+id/appbar_layout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:theme="@style/ThemeOverlay.AppCompat.ActionBar">
        </android.support.v7.widget.Toolbar>

        <TextView
            android:layout_centerInParent="true"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/app_name"/>

    </RelativeLayout>
</android.support.design.widget.AppBarLayout>

But it would be really nice if the official Android API could support this the same way flutter does. Maybe you'd like to send a feature request to the Material Components Android Issue Tracker?

How about textAlignment="center"? a RelativeLayout does the trick, when AppCompatTextView has set layout_width="match_parent"; for example:

<?xml version="1.0" encoding="utf-8"?>
<layout
    xmlns:android="http://schemas.android.com/apk/res/android">

    <androidx.appcompat.widget.LinearLayoutCompat
        android:id="@+id/customView"
        android:minHeight="?android:attr/actionBarSize"
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        android:orientation="vertical"
        android:gravity="top">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <!-- Home Button -->
            <include
                layout="@layout/button_home_menu"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="start"/>

            <androidx.appcompat.widget.LinearLayoutCompat
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="vertical"
                android:padding="8dp">

                <androidx.appcompat.widget.AppCompatTextView
                    android:id="@+id/title"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:text="@string/app_name"
                    android:textAlignment="center"
                    android:textAppearance="?android:attr/textAppearanceLarge"
                    android:textSize="18sp"
                    android:textStyle="bold"/>

                <androidx.appcompat.widget.AppCompatTextView
                    android:id="@+id/subtitle"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:text="@string/app_version"
                    android:textAlignment="center"
                    android:textAppearance="?android:attr/textAppearanceMedium"
                    android:textSize="12sp"
                    android:textStyle="bold"/>

            </androidx.appcompat.widget.LinearLayoutCompat>

        </RelativeLayout>

    </androidx.appcompat.widget.LinearLayoutCompat>

</layout>

the down-side is, that when showing several menu-items as action buttons - or when displaying extraordinary long strings as title, the title may overlap them - but when only showing one or two action buttons in combination with a title that fits the visually available width, this works just fine - that's because menu config ifRoom would always apply, because there is room. else one could only measure, which side of the toolbar has the most wide items' container - and then adjust the width on the other side's items' container. scaling the font-size depending on the available room might also be an option, to make it fit dynamically.

No official way to do it but subclassing provides most coverage without crazy tricks.

https://gist.github.com/bmc08gt/40a151e93969f2633b9b92bca4b31e83

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