android - AppBarLayout elevation change is delayed on appCompat v24.0.0

Question

In Appcompat v24.0.0 causes rendering of shadow/elevation to AppbarLayout after Activity is visible. And a lag can easily be seen in shadow drawing to AppbarLayout.

And this lag was not there in previous Appcompat library version.

Tested using both Appcompat v24.0.0 and Appcompat v23.4.0, shadow drawing clearly seen in the new version.

Answer 1

This is a bug in Appcompat v24.0.0.

References: https://code.google.com/p/android/issues/detail?id=213895

In order to minimize the delay in elevation drawing, set the duration to 1ms in your own StateListAnimator and apply it to AppbarLayout.

appbar_always_elevated.xml in animator-v21 folder under res directory.

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

    <item>
        <objectAnimator android:propertyName="elevation"
                        android:valueTo="8dp"
                        android:valueType="floatType"
                        android:duration="1"/>
    </item>

</selector>

In AppbarLayout :

<android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="300dp"
        android:fitsSystemWindows="true"
        android:stateListAnimator="@animator/appbar_always_elevated"
        android:theme="@style/AppTheme.AppBarOverlay">

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