multiline-collapsingtoolbar is a replacement for CollapsingToolbarLayout from the Android Design Support Library which can deal with multiline titles (currently hard-coded to a maximum of 3 lines) in the expanded state. When collapsing the toolbar, the lower lines of the title fade away to leave only the top line visible.

Here you can see the library in use in the Web Opac App:

Background Image credit: Tom Murphy VII on Wikimedia Commons, CC-BY-SA 3.0

If you are using Gradle and the JCenter Maven Repository, installing the library is as simple as adding a new dependency statement.

dependencies {
    compile 'net.opacapp:multiline-collapsingtoolbar:1.0.0'
}

The library's public API is identical to the version from the support library, so you can use it as a drop-in replacement.

As the Design Support Library, it should be compatible with API 7 (Android 2.1) and above.

XML layout example:

<android.support.design.widget.AppBarLayout
        android:layout_height="192dp"
        android:layout_width="match_parent">
    <net.opacapp.multilinecollapsingtoolbar.CollapsingToolbarLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">
        <android.support.v7.widget.Toolbar
                android:layout_height="?attr/actionBarSize"
                android:layout_width="match_parent"
                app:layout_collapseMode="pin"/>
    </net.opacapp.multilinecollapsingtoolbar.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>

You can find a simple demo application in the demo module.

Most of the code is copied from the original Support Library classes, the only changes (apart from the package name, imports and automatic code reformatting) are in the CollapsingTextHelper class. The changes there are marked with comments.

The current version 1.0.0 of the library is based on the code from the Design Support Library version 23.1.1.