app with custom theme in android, error: You need to use a Theme.AppCompat theme (or descendant) with this activity

Question

here is my xml manifest file:

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.SubHunter">
        <activity android:name=".SubHunter"
            android:theme="@android:style/Theme.NoTitleBar.Fullscreen"
            android:screenOrientation="landscape">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

and here are 2 theme files (came by default with the empty activity): theme:

<resources xmlns:tools="http://schemas.android.com/tools">
    <!-- Base application theme. -->
    <style name="Theme.SubHunter" parent="Theme.MaterialComponents.DayNight.DarkActionBar">
        <!-- Primary brand color. -->
        <item name="colorPrimary">@color/purple_500</item>
        <item name="colorPrimaryVariant">@color/purple_700</item>
        <item name="colorOnPrimary">@color/white</item>
        <!-- Secondary brand color. -->
        <item name="colorSecondary">@color/teal_200</item>
        <item name="colorSecondaryVariant">@color/teal_700</item>
        <item name="colorOnSecondary">@color/black</item>
        <!-- Status bar color. -->
        <item name="android:statusBarColor" tools:targetApi="l">?attr/colorPrimaryVariant</item>
        <!-- Customize your theme here. -->
    </style>
</resources>

theme (night):

<resources xmlns:tools="http://schemas.android.com/tools">
    <!-- Base application theme. -->
    <style name="Theme.SubHunter" parent="Theme.MaterialComponents.DayNight.DarkActionBar">
        <!-- Primary brand color. -->
        <item name="colorPrimary">@color/purple_200</item>
        <item name="colorPrimaryVariant">@color/purple_700</item>
        <item name="colorOnPrimary">@color/black</item>
        <!-- Secondary brand color. -->
        <item name="colorSecondary">@color/teal_200</item>
        <item name="colorSecondaryVariant">@color/teal_200</item>
        <item name="colorOnSecondary">@color/black</item>
        <!-- Status bar color. -->
        <item name="android:statusBarColor" tools:targetApi="l">?attr/colorPrimaryVariant</item>
        <!-- Customize your theme here. -->
    </style>
</resources>

error has many lines, beginning with:

2021-03-21 13:40:10.574 18926-18926/? E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.subhunter, PID: 18926 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.subhunter/com.example.subhunter.SubHunter}: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.

not sure what to do, new to android, trying to build a game with canvas with custom theme, no xml file for game.

Dam Dam · Accepted Answer · 2021-03-21T18:20:13

There is a forum with some answers to your Question take a look at this forum:

How to Make my Android App FullScreen via Android Manifest?

Most of them say that you need to change the ActivityCompat to Activity and add the code in the onCreate method.

requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, 
                            WindowManager.LayoutParams.FLAG_FULLSCREEN);

another option as you can see in the forum is to apply some some styles in the theme:

<item name="android:windowNoTitle">true</item>
    <item name="android:windowFullscreen">true</item>

If the problem persists we can investigate.

app with custom theme in android, error: You need to use a Theme.AppCompat theme (or descendant) with this activity

1 Answers