如何 show/hide FAB on scroll Recycler view with coordinator parent

Question

我有一个 activity 和协调器 layout.inside activity 有一个带有 Recycler 视图和浮动的片段 button.how 我可以 show/hide 在滚动时浮动按钮吗回收站查看并避免使用 fab 行为？！

在activity布局中： CoordinatorLayout----->AppBarLayout---->Toolbar and FrameLayout and Bottom bar view

在片段布局中： RelativeLayout---->Recycler视图和浮动按钮

我想实现类似 Google+ 主页的功能。我该如何实现这种情况？

临时我使用这个解决方案来解决我的问题：

在我的片段中通过界面使用 activity 的协调器布局和 show/hide 具有 fab 行为的 fab ......直到我找到更好的解决方案！！！

Answer 1

此代码工作正常：

 mRecycler.addOnScrollListener(new RecyclerView.OnScrollListener() {
                @Override
                public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                    if(dy > 0){
                        mFab.hide();
                    } else{
                        mFab.show();
                    }

                    super.onScrolled(recyclerView, dx, dy);
                }
            });

你不能这样做：

app:layout_anchor="@id/listView"
app:layout_anchorGravity="bottom|end"

看here:

There is no support built-in for CoordinatorLayout to work with ListView according to this Google post.

Answer 2

我修改了 Leondro 的方法，使 FAB 在滚动时隐藏并在滚动停止时显示。

scrollListener = new RecyclerView.OnScrollListener() {  
    @Override
    public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
        switch (newState) {
            case RecyclerView.SCROLL_STATE_IDLE:
                fab.show();
                break;
            default:
                fab.hide();
                break;
        }
        super.onScrollStateChanged(recyclerView, newState);
    }
}; 

rv.clearOnScrollListeners();
rv.addOnScrollListener(scrollListener);

Answer 3

这是可行的解决方案：

class HideOnScrollFabBehavior(context: Context?, attrs: AttributeSet?) : FloatingActionButton.Behavior() {

    // changes visibility from GONE to INVISIBLE when fab is hidden because
    // due to CoordinatorLayout.onStartNestedScroll() implementation
    // child view's (here, fab) onStartNestedScroll won't be called anymore
    // because it's visibility is GONE
    private val listener = object : FloatingActionButton.OnVisibilityChangedListener() {
        override fun onHidden(fab: FloatingActionButton?) {
            fab?.visibility = INVISIBLE
        }
    }

    override fun onStartNestedScroll(coordinatorLayout: CoordinatorLayout, child: FloatingActionButton, directTargetChild: View, target: View, axes: Int, type: Int): Boolean {
        return axes == ViewCompat.SCROLL_AXIS_VERTICAL // Ensure we react to vertical scrolling
                || super.onStartNestedScroll(coordinatorLayout, child, directTargetChild, target, axes, type)
    }

    override fun onNestedScroll(coordinatorLayout: CoordinatorLayout, child: FloatingActionButton, target: View, dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int, type: Int, consumed: IntArray) {
        super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed, type, consumed)
        if (!target.canScrollVertically(1) && dyConsumed > 0 && child.visibility == VISIBLE) {
            // hide the FAB when scroll view reached its bottom
            child.hide(listener)
        } else if (dyConsumed < 0 && child.visibility != VISIBLE) {
            // show the FAB on scroll up
            child.show()
        }
    }

}

Answer 4

将此添加到 FAB：

应用：layout_behavior="@string/hide_bottom_view_on_scroll_behavior"

Answer 5

Kotlin 中的解决方案

recycler_view = findViewById(R.id.recycler_view)

        recycler_view.addOnScrollListener(object : RecyclerView.OnScrollListener(){
            override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
                if(dy > 0){
                    fab.hide();
                } else{
                    fab.show();
                }
                super.onScrolled(recyclerView, dx, dy)

            }
        })

如何 show/hide FAB on scroll Recycler view with coordinator parent

how to show/hide FAB on scroll Recycler view with coordinator parent

android

floating-action-button

android-recyclerview

recyclerview-layout

临时我使用这个解决方案来解决我的问题：