在 RecyclerView 的滚动上隐藏 FloatingActionButton

Question

我想在RecyclerView 的滚动条上隐藏/显示FloatingActionButton。

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 是这个布局的父布局。

    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();
        }
    }
}

将此布局行为用于FloatingActionButton。

当我看到logcat 时，只有构造函数被调用。 onNestedScroll() 在我滚动列表时不会被调用。

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中：

@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，您需要覆盖这个：

 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;
}

祝你好运！

更新

你的ScrollAwareFABBehavior 应该是这样的：

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();
        }
    }
}

另外，它使用com.android.support:design:23.0.1进行了测试

Answer 4

短而简单的解决方案：

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 Material Components for Android 并且您的 FAB 在 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" 
            ... />

Answer 6

我就是这样做的。这个对我有用！如果你不知道如何实现，你可以在这个链接https://guides.codepath.com/android/floating-action-buttons查看详细信息

public class ScrollAwareFABBehavior extends FloatingActionButton.Behavior {

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

    @Override
    public void onNestedScroll(CoordinatorLayout coordinatorLayout, FloatingActionButton child, View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed) {
        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.GONE) {
            child.show();
        }
    }

    @Override
    public boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, FloatingActionButton child, View directTargetChild, View target, int nestedScrollAxes) {
        return nestedScrollAxes == ViewCompat.SCROLL_AXIS_VERTICAL;
    }
}

Answer 7

如果您没有使用协调器布局，并且想要平滑地隐藏和显示 FAB。并且您想实现自己的逻辑以在向下滚动时隐藏 fab，并在向上滚动时显示它。

那么这里就是kotlin中的解决方案，

• 声明一个变量，

var scrollingDown = false

• 然后创建一个监听器，

recycler_view_id.addOnScrollListener(object : RecyclerView.OnScrollListener() {

            override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
                super.onScrolled(recyclerView, dx, dy)

                if (scrollingDown && dy >= 0) {
                    scrollingDown = !scrollingDown
                    id_show_media_fab.startAnimation(
                        AnimationUtils.loadAnimation(
                            getApplicationContext(),
                            R.anim.fab_close
                        )
                    )
                } else if (!scrollingDown && dy < 0) {
                    scrollingDown = !scrollingDown
                    id_show_media_fab.startAnimation(
                        AnimationUtils.loadAnimation(
                            getApplicationContext(),
                            R.anim.fab_open
                        )
                    )
                }

            }
        })

• 创建动画资源文件

fab_open.xml

<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:fillAfter="true">
    <scale
        android:duration="300"
        android:fromXScale="0.0"
        android:fromYScale="0.0"
        android:interpolator="@android:anim/linear_interpolator"
        android:pivotX="50%"
        android:pivotY="100%"
        android:toXScale="0.9"
        android:toYScale="0.9" />
    <alpha
        android:duration="300"
        android:fromAlpha="0.0"
        android:interpolator="@android:anim/accelerate_interpolator"
        android:toAlpha="1.0" />
</set>

fab_close.xml

just change 

android:fromXScale="0.8"
android:fromYScale="0.8"

Answer 8

我创建了一个 自定义 RecyclerView，它已准备好 OnUpDownScrollListener、OnLeftRightScrollListener： p>

代码：

MBRecyclerView.java

public class MBRecyclerView extends RecyclerView {

    private OnScrollListener wrappedUpDownScrollListener;
    private OnScrollListener wrappedLeftRightScrollListener;

    public MBRecyclerView(Context context) {
        super(context);
        init();
    }

    public MBRecyclerView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public MBRecyclerView(Context context, @Nullable AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init();
    }

    private void init() {
    }

    // region Scrolling Listener for Up, Down, Left and Right
    public void setOnUpDownScrollListener(final OnUpDownScrollListener onUpDownScrollListener) {
        if (wrappedUpDownScrollListener == null) {
            wrappedUpDownScrollListener = getWrappedUpDownScrollListener(onUpDownScrollListener);
            addOnScrollListener(wrappedUpDownScrollListener);
        }
    }

    public void removeOnUpDownScrollListener() {
        if (wrappedUpDownScrollListener != null) {
            removeOnScrollListener(wrappedUpDownScrollListener);
            wrappedUpDownScrollListener = null;
        }
    }

    public void setLeftOnRightScrollListener(final OnLeftRightScrollListener onLeftRightScrollListener) {
        if (wrappedLeftRightScrollListener == null) {
            wrappedLeftRightScrollListener = getWrappedLeftRightScrollListener(onLeftRightScrollListener);
            addOnScrollListener(wrappedLeftRightScrollListener);
        }
    }

    public void removeOnLeftRightScrollListener() {
        if (wrappedLeftRightScrollListener != null) {
            removeOnScrollListener(wrappedLeftRightScrollListener);
            wrappedLeftRightScrollListener = null;
        }
    }

    private OnScrollListener getWrappedUpDownScrollListener(final OnUpDownScrollListener onUpDownScrollListener) {
        return new OnScrollListener() {
            @Override
            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                if (onUpDownScrollListener != null) {
                    // Negative to check scrolling up, positive to check scrolling down
                    if (!recyclerView.canScrollVertically(-1)) {
                        onUpDownScrollListener.onScrolledToTop();
                    } else if (!recyclerView.canScrollVertically(1)) {
                        onUpDownScrollListener.onScrolledToBottom();
                    }
                    if (dy > 0) {
                        onUpDownScrollListener.onScrollDown(dy);
                    } else if (dy < 0) {
                        onUpDownScrollListener.onScrollUp(dy);
                    }
                }
            }

            @Override
            public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
                if (newState == RecyclerView.SCROLL_STATE_IDLE) {
                    if (onUpDownScrollListener != null) {
                        onUpDownScrollListener.onScrollStopped();
                    }
                }
            }
        };
    }

    private OnScrollListener getWrappedLeftRightScrollListener(final OnLeftRightScrollListener onLeftRightScrollListener) {
        return new OnScrollListener() {
            @Override
            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                if (onLeftRightScrollListener != null) {
                    // Negative to check scrolling left, positive to check scrolling right
                    if (!recyclerView.canScrollHorizontally(-1)) {
                        onLeftRightScrollListener.onScrolledToMostLeft();
                    } else if (!recyclerView.canScrollVertically(1)) {
                        onLeftRightScrollListener.onScrolledToMostRight();
                    }
                    if (dy > 0) {
                        onLeftRightScrollListener.onScrollRight(dx);
                    } else if (dy < 0) {
                        onLeftRightScrollListener.onScrollLeft(dx);
                    }
                }
            }

            @Override
            public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
                if (newState == RecyclerView.SCROLL_STATE_IDLE) {
                    if (onLeftRightScrollListener != null) {
                        onLeftRightScrollListener.onScrollStopped();
                    }
                }
            }
        };
    }

    public abstract class OnUpDownScrollListener {
        public void onScrollUp(int dy) {}

        public void onScrollDown(int dy) {}

        public void onScrolledToTop() {}

        public void onScrolledToBottom() {}

        public void onScrollStopped() {}
    }

    public abstract class OnLeftRightScrollListener {
        public void onScrollLeft(int dx) {}

        public void onScrollRight(int dx) {}

        public void onScrolledToMostRight() {}

        public void onScrolledToMostLeft() {}

        public void onScrollStopped() {}
    }
    // endregion
}

用法（UpDownScrollListener）：

    mbRecyclerView.setOnUpDownScrollListener(new MBRecyclerView.OnUpDownScrollListener() {
        @Override
        public void onScrollUp(int dy) {
            // show
        }

        @Override
        public void onScrollDown(int dy) {
            // hide
        }

        // aditional functions:
        public void onScrolledToTop() {}
        public void onScrolledToBottom() {}
        public void onScrollStopped() {}
    });

同样你可以通过设置来处理左右滚动

setOnLeftRightScrollListener

我希望它可以帮助某人:)

Answer 9

解决办法在：F.A.B Hides but Doesn't Show

问题是 Android 25.0.x+ 将视图设置为 GONE，这就是侦听器不报告更改的原因。

Answer 10

所有在 Behavior 路径和 onNestedScroll（而不是 recyclerview 侦听器）上的答案都没有评论 onNestedScroll 在滚动时将被多次调用的事实。这意味着 child.show() 和 child.hide() 也将被多次调用。尽管 show() 和 hide() 旨在处理这种情况，但它们仍然运行大量代码并创建一些对象，这些对象乘以调用 onNestedScroll 的次数，导致创建了许多不必要的对象。

考虑到这一点，并且因为我想运行不同的动画而不是默认的 show() 和 hide()，我想出了以下 Behavior 实现：

public class ScrollAwareFABBehavior extends CoordinatorLayout.Behavior<FloatingActionButton>  {

private static final String TAG = "ScrollAwareFABBehavior";

private boolean fabAnimationStarted = false;
private boolean flingHappened = false;

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

@Override
public boolean onStartNestedScroll(@NonNull CoordinatorLayout coordinatorLayout, @NonNull FloatingActionButton child, @NonNull View directTargetChild, @NonNull View target, int axes, int type) {

    if (target instanceof RecyclerView) {
        return true;
    }
    return false;
}

@Override
public void onStopNestedScroll(@NonNull CoordinatorLayout coordinatorLayout, @NonNull final FloatingActionButton child, @NonNull View target, int type) {
    super.onStopNestedScroll(coordinatorLayout, child, target, type);

    // If animation didn't start, we don't need to care about running the restore animation.
    // i.e.: when the user swipes to another tab in a viewpager. The onNestedPreScroll is never called.
    if (!fabAnimationStarted) {
        return;
    }

    // Animate back when the fling ended (TYPE_NON_TOUCH)
    // or if the user made the touch up (TYPE_TOUCH) but the fling didn't happen.
    if (type == ViewCompat.TYPE_NON_TOUCH || (type == ViewCompat.TYPE_TOUCH && !flingHappened)) {
        ViewCompat.animate(child).translationY(0).start();

        fabAnimationStarted = false;
    }
}

@Override
public boolean onNestedFling(@NonNull CoordinatorLayout coordinatorLayout, @NonNull FloatingActionButton child, @NonNull View target, float velocityX, float velocityY, boolean consumed) {

    // We got a fling. Flag it.
    flingHappened = true;
    return false;

}

@Override
public void onNestedPreScroll(@NonNull CoordinatorLayout coordinatorLayout, @NonNull FloatingActionButton child, @NonNull View target, int dx, int dy, @NonNull int[] consumed, int type) {

    if (!fabAnimationStarted) {
        Log.d(TAG, "onStartNestedScroll: animation is starting");
        fabAnimationStarted = true;
        flingHappened = false;
        CoordinatorLayout.LayoutParams lp = (CoordinatorLayout.LayoutParams) child.getLayoutParams();

        ViewCompat.animate(child).translationY(child.getHeight() + lp.bottomMargin).start();

    }
}
}

Answer 11

浮动动作按钮在滚动时隐藏，在滚动停止时显示。

  recylerview.addOnScrollListener(new RecyclerView.OnScrollListener() {
                @Override
                public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
                    switch (newState) {
                        case RecyclerView.SCROLL_STATE_IDLE:
                            addExpenseBtn.show();
                            break;
                        default:
                            addExpenseBtn.hide();
                            break;
                    }
                    super.onScrollStateChanged(recyclerView, newState);
                }
            });

Answer 12

//lv = 列表视图

    lv.setOnScrollListener(new AbsListView.OnScrollListener() {
        @Override
        public void onScrollStateChanged(AbsListView view, int scrollState) {

        }

        @Override
        public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
            fab.setVisibility(view.getFirstVisiblePosition() == 0 ? View.VISIBLE : View.INVISIBLE);
        }
    });

Answer 13

我在 RecyclerView.Adapter 的 onBindViewHolder 方法中使用它来将列表中最后一项的底部边距设置为 72dp，以便它会向上滚动到浮动操作按钮上方。

这不需要列表中的虚拟条目。

@Override
public void onBindViewHolder(ViewHolder holder, int position) {
    // other binding code goes here.

    if (position + 1 == getItemCount()) {
        // set bottom margin to 72dp.
        setBottomMargin(holder.itemView, (int) (72 * Resources.getSystem().getDisplayMetrics().density));
    } else {
        // reset bottom margin back to zero. (your value may be different)
        setBottomMargin(holder.itemView, 0);
    }
}

public static void setBottomMargin(View view, int bottomMargin) {
    if (view.getLayoutParams() instanceof ViewGroup.MarginLayoutParams) {
        ViewGroup.MarginLayoutParams params = (ViewGroup.MarginLayoutParams) view.getLayoutParams();
        params.setMargins(params.leftMargin, params.topMargin, params.rightMargin, bottomMargin);
        view.requestLayout();
    }
}

Answer 14

有点晚了，但对我有用。

//This only works on Android M and above
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
    recyclerView.setOnScrollChangeListener(new View.OnScrollChangeListener() {
        @Override
        public void onScrollChange(View v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) {
        if (scrollY > oldScrollY && fab.isShown()) {
            fab.hide();
        } else if (scrollY < oldScrollY && !fab.isShown()) {
            fab.show();
        }
    }
});

当scrollY 大于oldScrollY 时，这意味着用户已经向下滚动，所以我们只需要检查 FAB 是否显示。如果是，我们将其隐藏。

scrollY 小于oldScrollY 表示向上滚动。我们检查 FAB 是否仍然隐藏以显示它。

Answer 15

试试这个

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

                //Customize your if statement  
                if (recyclerView.computeVerticalScrollOffset() > recyclerView.getHeight() * 2) {
                    if (!fab.isShown()) {
                        fab.show();
                    }
                } else {
                    fab.hide();
                }
            }
        });

享受吧。