系统自带水波效果

<!-- Resources/drawable/btn_default.xml -->
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <stroke android:width="1dp" android:color="#67c23a"/>
    <solid android:color="#67c23a"/>
    <corners android:radius="40dp"/>
    <padding android:left="15dp" android:right="15dp"/>
</shape>

<!-- Resources/drawable/btn_ripple.xml -->
<?xml version="1.0" encoding="utf-8"?>
<ripple xmlns:android="http://schemas.android.com/apk/res/android"
    android:color="#ffffff">
    <item android:drawable="@drawable/btn_default" />
</ripple>

<!-- 布局 -->
<Button
        android:id="@+id/btn_01"
        android:layout_marginBottom="10dp"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:background="@drawable/btn_ripple"
        android:textColor="#ffffff"
        android:text="按钮(扩散组件自带)" />

第三方水波效果

• 安装
  

<android_by_csharp.Scripts.BtnRippleView
        android:id="@+id/btn_02"
        android:layout_below="@id/btn_01"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:layout_marginBottom="10dp"
        ripple:rv_centered="true">
        <Button
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@drawable/btn_default"
            android:textColor="#ffffff"
            android:text="按钮(第三方依赖)" />
</android_by_csharp.Scripts.BtnRippleView>

// Scripts/BtnRippleView.cs
using Android.Content;
using Android.Graphics;
using Android.Util;
using Com.Andexert.Library;

namespace android_by_csharp.Scripts
{
    public class BtnRippleView : RippleView
    {
        public BtnRippleView(Context context) : base(context) { }
        public BtnRippleView(Context context, IAttributeSet attrs): base(context, attrs) { } 
        public BtnRippleView(Context context, IAttributeSet attrs, int defStyle): base(context, attrs, defStyle) { }

        public override void Draw(Canvas canvas)
        {
            canvas.Save();
            base.Draw(canvas);
        }
    }
}