自定义样式不适用于 Android 中的按钮

Question

I have a project with two themes in res/values/themes. I want to add my own button style. I create values/styles.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="android:colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="android:colorAccent">@color/colorAccent</item>
    </style>

    <style name="BeatBoxButton">
        <item name="android:background">@color/dark_blue</item>
    </style>
</resources>

Then I add style attribute to Button :

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
>
    <data>
        <variable
            name="viewModel"
            type="com.example.beatbox.SoundViewModel"
        />
    </data>
    <Button
        style="@style/BeatBoxButton"
        android:layout_width="match_parent"
        android:layout_height="110dp"
        android:padding="7dp"
        android:layout_margin="7dp"
        android:text="@{viewModel.title}"
        android:onClick="@{() -> viewModel.onButtonClick()}"
        tools:text="@string/sound_item_btn_text"
    />
</layout>

Now I want to see my buttons with dark_blue background. But style doesn't apply. Why? And what I need to do to apply BeatBoxButton style?

PS: And I have res/values/colors.xml too with

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="colorPrimary">#008577</color>
    <color name="colorPrimaryDark">#00574B</color>
    <color name="colorAccent">#D81B60</color>

    <color name="red">#F44336</color>
    <color name="dark_red">#C3352B</color>
    <color name="gray">#607D8B</color>
    <color name="soothing_blue">#0083BF</color>
    <color name="dark_blue">#005A8A</color>
</resources>

Answer 1

You are missing the parent attribute in your style, in addition to this, the background attribute is mean to be used with a drawable (an image, a xml...) because the background of a button is more complex than just a color, what you are looking for is the Tint attribute.

Tint attribute is used to give a color tint to the given button.

<style name="BeatBoxButton" parent="@android:style/Widget.Button">
        <item name="android:backgroundTint">@color/dark_blue</item>
</style>

Answer 2

Change theme in AndroidManifest to "themeApp" did the trick. And we even don't need parent attribute in our custom style!