android ScrollView 吸顶效果上划隐藏头布局

我就是我 2024-04-17 17:24 45阅读 0赞

效果图：

![图有点渣][20190123155931804.gif]

*  有两个相同吸顶的View
 *  viewA在ScrollView中
 *  viewB与ScrollView同级
 *  根据ScrollView滑动距离判断同级的viewB 是否显示
 *  当滑动的距离大于viewA到顶部的距离，viewB就显示，反之隐藏

#### xml代码 ####

<?xml version="1.0" encoding="utf-8"?/>
     
      <com.yechaoa.stickscrollview.MyScrollView
        android:id="@+id/scrollView"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
    
    <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">
    
            <TextView
                android:id="@+id/tv_top_view"
                android:layout_width="match_parent"
                android:layout_height="200dp"
                android:background="@color/colorPrimary"
                android:gravity="center"
                android:padding="20dp"
                android:text="内容区"
                android:textColor="#fff"
                android:textSize="20sp"/>
            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="@color/colorAccent"
                android:gravity="center"
                android:padding="20dp"
                android:text="@string/app_name"
                android:textColor="#fff"
                android:textSize="20sp"/>
    
         <TextView
                android:layout_width="match_parent"
                android:layout_height="800dp"
                android:background="@color/colorPrimary"
                android:gravity="center"
                android:padding="20dp"
                android:text="内容区"
                android:textColor="#fff"
                android:textSize="20sp"/>
    
     </ LinearLayout>;
    
     </com.yechaoa.stickscrollview.MyScrollView>;
    
     <TextView
        android:id="@+id/tv_stick_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/colorAccent"
        android:gravity="center"
        android:padding="20dp"
        android:text="@string/app_name"
        android:textColor="#fff"
        android:textSize="20sp"
        android:visibility="gone"/>
     </RelativeLayout>

#### java代码 ####

mTopView = findViewById(R.id.tv_top_view);
            mStickView = findViewById(R.id.tv_stick_view);
            MyScrollView mScrollView = findViewById(R.id.scrollView);
         mScrollView.setScrollViewListener(new MyScrollView.ScrollViewListener() {
            @Override
            public void onScrollChanged(MyScrollView scrollView, int x, int y, int oldx, int oldy) {
                if (y > mTopView.getHeight())
                    mStickView.setVisibility(View.VISIBLE);
                else
                    mStickView.setVisibility(View.GONE);
            }
        });

y 就是ScrollView 滑动的距离

点击到顶部：

mScrollView.scrollTo(0, mTopView.getHeight());

#### 带滑动监听的ScrollView ####

package com.yechaoa.stickscrollview;
    
    import android.content.Context;
    import android.util.AttributeSet;
    import android.widget.ScrollView;
    
    /**
     * Created by yechao on 2019/1/23.
     * Describe : 带滑动监听的scrollview
     */
     
    
     	public class MyScrollView extends ScrollView {
    
        public interface ScrollViewListener {
            void onScrollChanged(MyScrollView scrollView, int x, int y, int oldx, int oldy);
        }
    
        private ScrollViewListener scrollViewListener = null;
    
        public MyScrollView(Context context) {
            super(context);
        }
    
        public MyScrollView(Context context, AttributeSet attrs, int defStyle) {
            super(context, attrs, defStyle);
        }
    
        public MyScrollView(Context context, AttributeSet attrs) {
            super(context, attrs);
        }
    
        public void setScrollViewListener(ScrollViewListener scrollViewListener) {
            this.scrollViewListener = scrollViewListener;
        }
    
        @Override
        protected void onScrollChanged(int x, int y, int oldx, int oldy) {
            super.onScrollChanged(x, y, oldx, oldy);
            if (scrollViewListener != null) {
                scrollViewListener.onScrollChanged(this, x, y, oldx, oldy);
            }
        }
    
    }

[20190123155931804.gif]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/2c59f3c783c5402a8fe0f4cec63bbee7.gif