按钮样式在Android Studio中不起作用

Question

  <style name="buttonStartStyle">
    <item name="android:background">@drawable/button_style1</item>
    <item name="android:layout_margin">20dp</item>
    <item name="android:textColor">@color/white</item>
    <item name="android:textAllCaps">false</item>
    <item name="android:textSize">18sp</item>
    <item name="android:layout_width">match_parent</item>
    <item name="android:layout_height">wrap_content</item>
</style>

<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item>
    <shape android:shape="rectangle">
        <corners android:radius="50dp"/>
        <solid android:color="@color/smoothWhite"/>
        <size android:height="50dp"/>
        <gradient android:startColor="@color/green_card" android:endColor="@color/green_main"/>
    </shape>
</item>

<Button
    android:id="@+id/button"
    style="@style/buttonStartStyle"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Button"
    tools:layout_editor_absoluteX="121dp"
    tools:layout_editor_absoluteY="244dp" />

<resources xmlns:tools="http://schemas.android.com/tools">
<!-- Base application theme. -->
<style name="Theme.B_app" parent="Theme.MaterialComponents.DayNight.DarkActionBar">
    <!-- Primary brand color. -->
    <item name="colorPrimary">@color/green_dark</item>
    <item name="colorPrimaryVariant">@color/black</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>

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

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

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

<style name="buttonStartStyle">
    <item name="android:background">@drawable/button_style1</item>
    <item name="android:layout_margin">20dp</item>
    <item name="android:textColor">@color/white</item>
    <item name="android:textAllCaps">false</item>
    <item name="android:textSize">18sp</item>
    <item name="android:layout_width">match_parent</item>
    <item name="android:layout_height">wrap_content</item>
</style>

<style name="testStyle">
    <item name="android:background">@drawable/button_style2</item>
    <item name="android:layout_margin">20dp</item>
    <item name="android:textColor">@color/white</item>
    <item name="android:textAllCaps">false</item>
    <item name="android:textSize">18sp</item>
    <item name="android:layout_width">match_parent</item>
    <item name="android:layout_height">wrap_content</item>
</style>

<style name="FlatButton" parent="Theme.AppCompat.Light">
    <item name="android:textColor">@color/grey_dark</item>
    <item name="colorControlHighlight">@color/white</item>
</style>