最初折叠ActionBarLayout时，CollapsingToolbarLayout标题会消失

Question

When the app scroll down and app bar collapsed, the title disappear somehow and sometimes don't show again even after expanding the app bar.

here's a gif animation of my problem: animation.gif

here's my xml:

activity_main.xml:

<android.support.v4.widget.DrawerLayout
    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/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:openDrawer="start">

    <include
        layout="@layout/app_bar_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <android.support.design.widget.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:fitsSystemWindows="true"
        app:headerLayout="@layout/nav_header_main"
        app:menu="@menu/activity_main_drawer" />

</android.support.v4.widget.DrawerLayout>

app_bar.main:

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.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"
    android:fitsSystemWindows="true"
    tools:context=".ScrollingActivity">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/app_bar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:fitsSystemWindows="true"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/toolbar_layout"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:fitsSystemWindows="true"
            app:contentScrim="?attr/colorPrimary"
            app:layout_scrollFlags="scroll|exitUntilCollapsed"
            app:expandedTitleMarginStart="48dp"
            app:expandedTitleMarginEnd="64dp">

            <ImageView
                android:src="@drawable/book1"
                android:id="@+id/image"
                android:layout_width="match_parent"
                android:layout_height="240dp"
                android:scaleType="centerCrop"
                android:fitsSystemWindows="true"
                app:layout_collapseMode="parallax"
                app:layout_collapseParallaxMultiplier="0.5"
                app:layout_scrollFlags="scroll|enterAlways|enterAlwaysCollapsed"/>

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                app:layout_collapseMode="pin"
                app:popupTheme="@style/AppTheme.PopupOverlay"
                app:layout_scrollFlags="scroll|enterAlways"/>


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

    <include layout="@layout/content_main" />

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="@dimen/fab_margin"
        android:src="@android:drawable/ic_dialog_email"
        app:layout_anchor="@id/app_bar"
        app:layout_anchorGravity="bottom|right|end" />

</android.support.design.widget.CoordinatorLayout>

I even set title programmatically:

CollapsingToolbarLayout collapsingToolbar = (CollapsingToolbarLayout) findViewById(R.id.toolbar_layout);
collapsingToolbar.setTitle(getString(R.string.app_name));
collapsingToolbar.setTitleEnabled(true);

Answer 1

This is well known Bug described here . Chris Banes already done with workaround for this issue and its expected to be fixed in Future Release of Design Support Library

As per comment #7, Temporary Workaround could be as below :

Don't let the CollapsingToolbarLayout handle your title but add a TextView to it. Then, you can animate (scaling / translating) this custom title view by adding an OnOffsetChangedListener to the AppBarLayout containing the CollapsingToolbarLayout. This listener gives you the offset with which you can compute the relation of source to target height and therefore the new text size:

float scaledTextSize = collapsedTextSize + ((expandedTextSize - sourceTextSize) * ((float) Math.abs(offset) / appBarLayout.getTotalScrollRange()));

The text sizes can be either set manually or through the TextAppearance styles you use.

Edited I confirmed that this issue is being fixed now in latest support library version v23.1.0

Answer 2

删除app:contentScrim="?attr/colorPrimary"