disabling dark mode wont work in android application

I created an android application and when I downloaded it to my phone it appeared in dark mode.

I want my application to always be in light mode so I used the following:

super.onCreate(savedInstanceState);
AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);

But it still showed me the app in dark mode.

How can I completely disable it?

My styles.xml file is:

<style name="CustomActivityTheme" parent="@style/Theme.AppCompat.Light">
    <item name="android:actionBarStyle">@style/MyActionBar</item>
    <item name="actionBarStyle">@style/MyActionBar</item>
    <item name="android:windowActionBarOverlay">true</item>
    <!-- other activity and action bar styles here -->
</style>

<!-- style for the action bar backgrounds -->
<style name="MyActionBar" parent="@style/Widget.AppCompat.Light.ActionBar">
    <item name="android:background">@color/colorGraySearchText</item>
    <item name="background">@color/colorGraySearch</item>
    <item name="android:titleTextStyle">@style/MyTheme.ActionBar.TitleTextStyle</item>
    <item name="android:subtitleTextStyle">@style/MyTheme.ActionBar.TitleTextStyle</item>
    <item name="titleTextStyle">@style/MyTheme.ActionBar.TitleTextStyle</item>
    <item name="subtitleTextStyle">@style/MyTheme.ActionBar.TitleTextStyle</item>
</style>

<!-- Text -->
<style name="MyTheme.ActionBar.TitleTextStyle" parent="@android:style/TextAppearance">
    <item name="android:textColor">@color/colorGraySearchText</item>
    <item name="android:textSize">16dp</item>
</style>

<style name="CustomActivityTheme.NoActionBar">
    <item name="windowActionBar">false</item>
    <item name="windowNoTitle">true</item>
</style>

<style name="CustomActivityTheme.AppBarOverlay" parent="ThemeOverlay.AppCompat.Dark.ActionBar" />

<style name="CustomActivityTheme.PopupOverlay" parent="ThemeOverlay.AppCompat.Light" />

SOLUTION:

The following steps solved my problem:

Changing in my build.gradle (app) to :

compileSdkVersion 29

targetSdkVersion 29

adding the following line to any style in my style.xml:

<item name="android:forceDarkAllowed" tools:targetApi="q">false</item>

Thank you