Unwanted blank space in PreferenceFragmentCompat

Question

In my Android app i've defined a very basic PreferenceScreen:

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
    <ListPreference
        android:entries="@array/test_entries"
        android:entryValues="@array/test_values"
        android:key="key_test1"
        android:title="Test title 1" />

    <CheckBoxPreference
        android:key="key_test2"
        android:summary="Test description 1"
        android:title="Test title 2" />
</PreferenceScreen>

And implemented the corresponding PreferenceFragmentCompat class:

class SettingsFragment : PreferenceFragmentCompat() {

    override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
        setPreferencesFromResource(R.xml.settings, rootKey)
    }
}

The dependency i'm using:

implementation "com.android.support:preference-v7:28.0.0"

And the code for the layout that hosts the Fragment:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical"
    tools:context=".ui.activity.MainActivity">

    <android.support.v7.widget.Toolbar
        android:id="@+id/mainToolbar"
        android:layout_width="match_parent"
        android:layout_height="?android:attr/actionBarSize" />

    <fragment
        android:id="@+id/navHostFragment"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:defaultNavHost="true"
        app:navGraph="@navigation/navigation" />
</LinearLayout>

Everything is working fine, except there's a huge blank space on the left side of each preference:

What is the cause of this problem and how can i prevent it?

EDIT:

It seems the problem is the space for the icons are reserved, even if we use no icons for the preference entries.

Setting the icon attribute of the preference to @null has no effect.

Setting the iconSpaceReserved attribute to false solves the problem for the Preference items, but it has no effect on PreferenceCategory items.

Answer 1

If using AndroidX, add the following attribute to your Preferences (and Preference Categories if needed) in XML:

<Preference
    ...
    app:iconSpaceReserved="false"
    .../>