阴影效果样式：

实现方法：

1、创建自定义属性——attrs.xml文件

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="ShadowContainer">
        <attr name="containerShadowColor" format="color"/>
        <attr name="containerShadowRadius" format="dimension"/>
        <attr name="containerDeltaLength" format="dimension"/>
        <attr name="containerCornerRadius" format="dimension"/>
        <attr name="deltaX" format="dimension"/>
        <attr name="deltaY" format="dimension"/>
        <attr name="enable" format="boolean"/>
    </declare-styleable>
</resources>

2、创建自定义阴影背景ViewGroup

/**
 * 作者：created by meixi
 * 邮箱：[email protected]
 * 日期：2019/7/18 17
 */

public class ShadowContainer extends ViewGroup {
    private final float deltaLength;
    private final float cornerRadius;
    private final Paint mShadowPaint;
    private boolean drawShadow;

。。。。。。。。。。。。。

3、layout文件调用自定义背景view即可实现阴影效果

<com.administrator.facedete.test.ShadowContainer
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="50dp"
    android:layout_gravity="center"
    app:containerCornerRadius="5dp"
    app:containerDeltaLength="5dp"
    app:containerShadowColor="#095493"
    app:containerShadowRadius="5dp">

    <LinearLayout
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:background="@drawable/pt"
      />

</com.administrator.facedete.test.ShadowContainer>

自定义阴影demo链接：https://download.csdn.net/download/meixi_android/11387225

附阴影属性:

android:elevation="4dp"