Squashed icons in toolbar after change to Android SDK 26

Question

After changing my app from compiling/targeting SDK v25 to SDK v26, all of the menu icons in my app's toolbar are now squashed/squished/stretched.

Here's the relevant layout code:

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

            <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="?attr/actionBarSize"
                    android:background="?attr/colorPrimary"
                    android:theme="@style/AppTheme.AppBarOverlay" />

                <br.com.mauker.materialsearchview.MaterialSearchView
                    android:id="@+id/search_view"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent" />

            </RelativeLayout>

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

Here's a menu that squishes:

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

<item android:id="@+id/action_search"
    android:title="@string/search"
    android:icon="@drawable/ic_search_white_48dp"
    app:showAsAction="ifRoom" />

<item
    android:id="@+id/advanced_search"
    android:enabled="true"
    android:title="@string/advanced_search"
    app:showAsAction="never" />

</menu>

Here's another menu that squishes (they all do):

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

<item
    android:id="@+id/add_photo"
    android:enabled="true"
    android:title="@string/add_photo"
    android:icon="@drawable/ic_add_a_photo_white_48dp"
    app:showAsAction="ifRoom" />

</menu>

How it looks on SDK v25

How it looks on SDK v26

Answer 1

The matter is that the icon size is bigger then the expected. Obviously the scaling mechanism has changed in SDK 26 and now it leads to this UI bug. Make sure the toolbar icon resources are provided in the following sizes.

Updated:

Since the Toolbar min height abc_action_bar_default_height_material is 56dp and abc_action_bar_icon_vertical_padding_material is 16dp, the toolbar icons are meant to be with a min size of 24dp in mdpi:

drawable-mdpi - 24 x 24 px
drawable-hdpi - 36 x 36 px
drawable-xhdpi - 48 x 48 px
drawable-xxhdpi - 72 x 72 px
drawable-xxxhdpi - 96 x 96 px

Answer 2

I had this issue with version 26.0.0 of the appcompat-v7 support library. Updating to 26.0.2 fixed it :)

See here: https://issuetracker.google.com/issues/64207386