如何在Android中的Scroll上隐藏显示BottomNavigationView？

在Android应用程序中，有些时候需要在Scroll控件中隐藏和显示BottomNavigationView。本文将介绍如何实现此功能。

实现步骤

1. 在布局文件中添加ScrollView和BottomNavigationView控件，ScrollView控件中添加需要滚动的控件。

   <?xml version="1.0" encoding="utf-8"?>
   <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
       android:layout_width="match_parent"
       android:layout_height="match_parent">
   
       <ScrollView
           android:id="@+id/scroll_view"
           android:layout_width="match_parent"
           android:layout_height="match_parent">
   
           <LinearLayout
               android:id="@+id/content_layout"
               android:layout_width="match_parent"
               android:layout_height="wrap_content"
               android:orientation="vertical">
   
               <!--Add your scrollable content here-->
   
               <!--Add your scrollable content here-->
   
               <!--Add your scrollable content here-->
   
           </LinearLayout>
   
       </ScrollView>
   
       <com.google.android.material.bottomnavigation.BottomNavigationView
           android:id="@+id/bottom_nav_view"
           android:layout_width="match_parent"
           android:layout_height="wrap_content"
           android:layout_gravity="bottom"
           android:background="?android:attr/windowBackground"
           app:menu="@menu/bottom_nav_menu" />
   
   </FrameLayout>
   

2. 创建一个OnScrollChangeListener监听器，当ScrollView的滚动状态改变时在底部导航栏上显示或隐藏。

   scrollView.setOnScrollChangeListener(new OnScrollChangeListener() {
       @Override
       public void onScrollChange(View v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) {
           if (scrollY > oldScrollY) {
               // Scroll Down
               bottomNavigationView.setVisibility(View.GONE);
           }
           if (scrollY < oldScrollY) {
               // Scroll Up
               bottomNavigationView.setVisibility(View.VISIBLE);
           }
   
           if (scrollY == 0) {
               // Top of ScrollView
               bottomNavigationView.setVisibility(View.VISIBLE);
           }
   
           if (scrollY == (v.getChildAt(0).getMeasuredHeight() - v.getMeasuredHeight())) {
               // Bottom of ScrollView
               bottomNavigationView.setVisibility(View.VISIBLE);
           }
       }
   });
   

以上就是如何在Android中的Scroll上隐藏和显示BottomNavigationView的全部步骤。

完整代码

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ScrollView
        android:id="@+id/scroll_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <LinearLayout
            android:id="@+id/content_layout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">

            <!--Add your scrollable content here-->

            <!--Add your scrollable content here-->

            <!--Add your scrollable content here-->

        </LinearLayout>

    </ScrollView>

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bottom_nav_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        android:background="?android:attr/windowBackground"
        app:menu="@menu/bottom_nav_menu" />

</FrameLayout>

scrollView.setOnScrollChangeListener(new OnScrollChangeListener() {
    @Override
    public void onScrollChange(View v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) {
        if (scrollY > oldScrollY) {
            // Scroll Down
            bottomNavigationView.setVisibility(View.GONE);
        }
        if (scrollY < oldScrollY) {
            // Scroll Up
            bottomNavigationView.setVisibility(View.VISIBLE);
        }

        if (scrollY == 0) {
            // Top of ScrollView
            bottomNavigationView.setVisibility(View.VISIBLE);
        }

        if (scrollY == (v.getChildAt(0).getMeasuredHeight() - v.getMeasuredHeight())) {
            // Bottom of ScrollView
            bottomNavigationView.setVisibility(View.VISIBLE);
        }
    }
});