AndroidManifest.xml :

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

    <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/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

在 values/styles.xml 新增 MyTheme样式：

<resources>

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>

    <style name="MyTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <item name="colorPrimary">#ff880f</item>
        <item name="colorPrimaryDark">#ff0002</item>
        <item name="colorAccent">#ffcc00</item>
    </style>

</resources>

修改的 AndroidManifest.xml 上的样式：

android:theme="@style/AppTheme"

改成 ====>

android:theme="@style/MyTheme"

效果：