在RecyclerView的滚动上隐藏FloatingActionButton

Question

我想隐藏/显示FloatingActionButton滚动RecyclerView.

我的XML布局:

<android.support.design.widget.CoordinatorLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent" >

            <android.support.v7.widget.RecyclerView
                android:id="@+id/recyclerview_eventlist"
                android:layout_width="match_parent"
                android:layout_height="match_parent" />

            <android.support.design.widget.FloatingActionButton
                android:id="@+id/fab_createevent"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_margin="@dimen/fab_margin"
                app:layout_anchor="@id/recyclerview_eventlist"
                app:layout_anchorGravity="bottom|right|end"
                app:layout_behavior="com.eventizon.behavior.ScrollAwareFABBehavior"
                android:src="@drawable/ic_edit"
                app:backgroundTint="@color/custom_color_1"
                app:borderWidth="0dp" />
        </android.support.design.widget.CoordinatorLayout>

DrawerLayout是此布局的父布局.

    public class ScrollAwareFABBehavior extends FloatingActionButton.Behavior {


    private static final String TAG = "ScrollAwareFABBehavior";

    public ScrollAwareFABBehavior(Context context, AttributeSet attrs) {
        super();
        Log.e(TAG,"ScrollAwareFABBehavior");
    }

    @Override
    public void onNestedScroll(CoordinatorLayout coordinatorLayout,
            FloatingActionButton child, View target, int dxConsumed,
            int dyConsumed, int dxUnconsumed, int dyUnconsumed) {
        // TODO Auto-generated method stub
        super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed,
                dxUnconsumed, dyUnconsumed);
        Log.e(TAG,"onNestedScroll called");
        if (dyConsumed > 0 && child.getVisibility() == View.VISIBLE) {
            Log.e(TAG,"child.hide()");
            child.hide();
        } else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) {
            Log.e(TAG,"child.show()");
            child.show();
        }
    }
}

使用此布局行为FloatingActionButton.

当我看到logcat只有构造函数被调用.onNestedScroll()滚动列表时不会调用.

Answer 1

最简单的解决方案

recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener()
{
    @Override
    public void onScrolled(RecyclerView recyclerView, int dx, int dy)
    {
        if (dy > 0 ||dy<0 && fab.isShown())
        {
            fab.hide();
        }
    }

    @Override
    public void onScrollStateChanged(RecyclerView recyclerView, int newState)
    {
        if (newState == RecyclerView.SCROLL_STATE_IDLE)
        {
            fab.show();
        }

        super.onScrollStateChanged(recyclerView, newState);
    }
});

Answer 2

这应该适合你:

recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
    @Override
    public void onScrolled(RecyclerView recyclerView, int dx,int dy){
        super.onScrolled(recyclerView, dx, dy);

        if (dy >0) {
            // Scroll Down
            if (fab.isShown()) {
                fab.hide();
            }
        }
        else if (dy <0) {
            // Scroll Up
            if (!fab.isShown()) {
                fab.show();
            }
        }
     }
});

Answer 3

好的,这就是你需要的:

首先,由于您的FAB依赖于RecyclerView,因此将以下内容添加到您的行为类:

@Override
public boolean layoutDependsOn(CoordinatorLayout parent, FloatingActionButton child, View dependency) {
    if(dependency instanceof RecyclerView)
        return true;

    return false;
}

接下来,为了接收onNestedScroll()呼叫,您需要覆盖此:

 public boolean onStartNestedScroll(CoordinatorLayout parent, FloatingActionButton child, View directTargetChild, View target, int nestedScrollAxes) {

    //predict whether you will need to react to the RecyclerView's scroll;
    //if yes, return true, otherwise return false to avoid future calls
    //of onNestedScroll()
    return true;
}

祝好运!

更新

这是你ScrollAwareFABBehavior应该看起来像:

public class ScrollAwareFABBehavior extends FloatingActionButton.Behavior {
    private static final String TAG = "ScrollAwareFABBehavior";

    public ScrollAwareFABBehavior(Context context, AttributeSet attrs) {
        super();
    }

    public boolean onStartNestedScroll(CoordinatorLayout parent, FloatingActionButton child, View directTargetChild, View target, int nestedScrollAxes) {
        return true;
    }

    @Override
    public boolean layoutDependsOn(CoordinatorLayout parent, FloatingActionButton child, View dependency) {
        if(dependency instanceof RecyclerView)
            return true;

        return false;
    }

    @Override
    public void onNestedScroll(CoordinatorLayout coordinatorLayout,
                               FloatingActionButton child, View target, int dxConsumed,
                               int dyConsumed, int dxUnconsumed, int dyUnconsumed) {
        // TODO Auto-generated method stub
        super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed,
                dxUnconsumed, dyUnconsumed);

        if (dyConsumed > 0 && child.getVisibility() == View.VISIBLE) {    
            child.hide();
        } else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) {
            child.show();
        }
    }
}

此外,它是使用测试 com.android.support:design:23.0.1

Answer 4

简短的解决方案:

mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
    @Override
    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
        super.onScrolled(recyclerView, dx, dy);
        if (dy > 0 && mFloatingActionButton.getVisibility() == View.VISIBLE) {
            mFloatingActionButton.hide();
        } else if (dy < 0 && mFloatingActionButton.getVisibility() !=View.VISIBLE) {
            mFloatingActionButton.show();
        }
    }
});

Answer 5

如果您使用的是 Android 的 Material Components 并且您的 FAB 位于 CoordinatorLayout 内，那么您可以使用layout_behavior com.google.android.material.behavior.HideBottomViewOnScrollBehavior

   <com.google.android.material.floatingactionbutton.FloatingActionButton
            android:id="@+id/filter_fab"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            ...
            app:layout_behavior="@string/hide_bottom_view_on_scroll_behavior" 
            ... />