Live source code, floating window rolling gradient effect

Live source , Suspension window rolling gradient effect to achieve the relevant code
Customize first ScrollView
MyScrollView

import android.content.Context;
import android.util.AttributeSet;
import android.widget.ScrollView;

/** * @Author：Administrator * @E-mail： [email protected] * @Date：2020/8/6 9:43 * @Description： Description information  */
public class MyScrollView extends ScrollView {
    
    private OnScrollListener onScrollListener; public MyScrollView(Context context) {
    
        this(context, null);
    }

    public MyScrollView(Context context, AttributeSet attrs) {
    
        this(context, attrs, 0);
    }

    public MyScrollView(Context context, AttributeSet attrs, int defStyle) {
    
        super(context, attrs, defStyle);
    }

    public void setOnScrollListener(OnScrollListener onScrollListener) {
    
        this.onScrollListener = onScrollListener;
    }

    @Override protected void onScrollChanged(int l, int t, int oldl, int oldt) {
    
        super.onScrollChanged(l, t, oldl, oldt); if (onScrollListener != null) {
    
            onScrollListener.onScroll(t);
        }
    }

    public interface OnScrollListener {
    
        public void onScroll(int scrollY);
    }
}

Use... In layout MyScrollView

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/ll_parent"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <com.utils.MyScrollView
        android:id="@+id/scrollView"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <FrameLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:descendantFocusability="blocksDescendants"
                android:orientation="vertical">

                <View
                    android:id="@+id/imageview"
                    android:layout_width="match_parent"
                    android:layout_height="500dp"
                    android:background="@android:color/holo_blue_dark" />
				<!-- Displayed when sliding title（ Internal fixation view）-->
                <LinearLayout
                    android:id="@+id/ll_filter"
                    android:layout_width="match_parent"
                    android:layout_height="45dp"
                    android:background="#00EAFF"
                    android:orientation="horizontal"
                    android:gravity="center">

                    <TextView
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:gravity="center" />

                </LinearLayout>

                <View
                    android:layout_width="match_parent"
                    android:layout_height="1000dp"
                    android:background="@android:color/holo_green_light" />
                <View
                    android:layout_width="match_parent"
                    android:layout_height="500dp"
                    android:background="#f00" />
                    
                <RelativeLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content">
                    <androidx.recyclerview.widget.RecyclerView
                        android:id="@+id/recyclerView"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"/>
                </RelativeLayout>
            </LinearLayout>
			<!-- Shown on top after sliding title（ External fixation view）-->
            <LinearLayout
                android:id="@+id/ll_top"
                android:layout_width="match_parent"
                android:layout_height="45dp"
                android:background="#FF0000"
                android:orientation="horizontal">

                <TextView
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:gravity="center"
                    android:text=" External fixation View" />
                <androidx.recyclerview.widget.RecyclerView
                    android:id="@+id/recycler_view_home_title"
                    android:layout_width="match_parent"
                    android:layout_height="@dimen/dp_50"
                    android:layout_centerHorizontal="true"
                    android:layout_marginLeft="@dimen/dp_24"
                    android:layout_marginTop="@dimen/dp_12"
                    >

                </androidx.recyclerview.widget.RecyclerView>
            </LinearLayout>

        </FrameLayout>
    </com.utils.MyScrollView>

</LinearLayout>

kotlin
First write ScrollView monitor
scrollView.setOnScrollListener(this)
Color gradient , obtain imageview To set the gradient

override fun onScroll(scrollY: Int) {
    
    val mTop = scrollY.coerceAtLeast(ll_filter.top)
    ll_top.layout(0, mTop, ll_top.width, mTop + ll_top.height)

    /* *  Color gradient （ You can delete the following without gradient ） * */
    var imageHeight = imageview.getHeight() if (scrollY <= imageHeight) {
    
        val scale: Float = scrollY.toFloat() / imageHeight
        val alpha = 255 * scale
        //  It's just layout The background is transparent ( Imitates the sliding effect ) White transparent 
        ll_top.setBackgroundColor(Color.argb(alpha.toInt(), 255, 255, 255))
        //                           Set the text color , black , Increase transparency 
        //textView.setTextColor(Color.argb(alpha.toInt(), 0, 0, 0))
        Log.e("111", "y > 0 && y <= imageHeight")
    }
}

That's all Live source , Suspension window rolling gradient effect to achieve the relevant code , More content welcome to follow the article