android - 在滚动上隐藏/显示底部导航 View

Question

我必须在向上滚动时隐藏底部导航 View 并在向下滚动时显示。如何实现这个？我的布局是这样的

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


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_above="@+id/navigation"
        android:layout_alignParentTop="true"
        android:layout_marginBottom="5dp">

        <FrameLayout
            android:id="@+id/container1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
          />


    </LinearLayout>

    <android.support.design.widget.BottomNavigationView
        android:id="@+id/navigation"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:background="?android:attr/windowBackground"
        app:layout_scrollFlags="scroll|enterAlways|snap"
        app:menu="@menu/dashboard_slider_menu" />

</RelativeLayout>

我附上了 View 的截图。请检查一下。

Answer 1

更新只需将一个属性添加到 BottomNavigationView

AndroidX Material 库

<com.google.android.material.bottomnavigation.BottomNavigationView
 ....
 app:layout_behavior="com.google.android.material.behavior.HideBottomViewOnScrollBehavior"/>

支持库版本28.0.0或更高版本

<android.support.design.widget.BottomNavigationView
 ....
 app:layout_behavior="@string/hide_bottom_view_on_scroll_behavior"/>

Note:- Your XML should follow the structure of XML given below in old answer.

**旧答案(仍然有效)**

您需要一个辅助类来执行此操作。此解决方案类似于 Google Material Design Guideline.

创建一个类BottomNavigationViewBehavior

public class BottomNavigationViewBehavior extends CoordinatorLayout.Behavior<BottomNavigationView> {

    private int height;

    @Override
    public boolean onLayoutChild(CoordinatorLayout parent, BottomNavigationView child, int layoutDirection) {
        height = child.getHeight();
        return super.onLayoutChild(parent, child, layoutDirection);
    }

    @Override
    public boolean onStartNestedScroll(@NonNull CoordinatorLayout coordinatorLayout,
                                   BottomNavigationView child, @NonNull 
                                   View directTargetChild, @NonNull View target,
                                   int axes, int type)
    {
        return axes == ViewCompat.SCROLL_AXIS_VERTICAL;
    }

    @Override
    public void onNestedScroll(@NonNull CoordinatorLayout coordinatorLayout, @NonNull BottomNavigationView child,
               @NonNull View target, int dxConsumed, int dyConsumed,
               int dxUnconsumed, int dyUnconsumed, 
                @ViewCompat.NestedScrollType int type)
    {
       if (dyConsumed > 0) {
           slideDown(child);
       } else if (dyConsumed < 0) {
           slideUp(child);
       }
    }

    private void slideUp(BottomNavigationView child) {
        child.clearAnimation();
        child.animate().translationY(0).setDuration(200);
    }

    private void slideDown(BottomNavigationView child) {
        child.clearAnimation();
        child.animate().translationY(height).setDuration(200);
    }
}

要使用此行为，您需要使用协调器布局...

<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.kliff.digitaldwarka.activity.MainActivity">

    <android.support.design.widget.CoordinatorLayout
        android:id="@+id/coordinator_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <android.support.design.widget.AppBarLayout
            android:id="@+id/myAppBar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:descendantFocusability="beforeDescendants"
            android:focusableInTouchMode="true"
            android:theme="@style/AppTheme.AppBarOverlay"
            app:elevation="0dp">

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="?attr/colorPrimary"
                app:contentInsetStart="0dp"
                app:layout_scrollFlags="scroll|enterAlways"
                app:popupTheme="@style/AppTheme.PopupOverlay"/>
        </android.support.design.widget.AppBarLayout>

        <!---your RecyclerView/Fragment Container Layout-->
        <FrameLayout
             android:id="@+id/container"
             android:layout_width="match_parent"
             android:layout_height="match_parent"
             app:layout_behavior="@string/appbar_scrolling_view_behavior" />
        

         <android.support.design.widget.BottomNavigationView
             android:id="@+id/bottom_nav"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:layout_gravity="bottom"
             app:itemBackground="@color/white"
             app:menu="@menu/bottom_nav_menu" />

      </android.support.design.widget.CoordinatorLayout>

      <!---NavigationView-->
</android.support.v4.widget.DrawerLayout>

将此代码添加到包含底部导航的 Activity..

mBottomNavigationView = (BottomNavigationView) findViewById(R.id.bottom_nav);
CoordinatorLayout.LayoutParams layoutParams = (CoordinatorLayout.LayoutParams) mBottomNavigationView.getLayoutParams();
    layoutParams.setBehavior(new BottomNavigationViewBehavior());