How to collapse/expand a view based on scroll direction?

Question

I have a View and a RecyclerView housed in a LinearLayout. What I want to achieve is something like this:

https://material.google.com/patterns/scrolling-techniques.html#scrolling-techniques-behavior

Basically when I scroll the RecyclerView up, the View collapses. It expands if I scroll the RecyclerView down.

I've tried various methods but the animation stutters if the finger jerks around a scroll position. It only animates well if the finger does a deliberate scroll movement in one direction. How do I do this correctly?

Answer 1

You have to use Coordinator Layout with the CollapsingToolbarLayout

<android.support.design.widget.CoordinatorLayout
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"
android:clipToPadding="false">

<android.support.design.widget.AppBarLayout
    android:id="@+id/app_bar_layout"
    android:layout_width="match_parent"
    android:layout_height="210dp"
    android:stateListAnimator="@animator/appbar_always_elevated" //I put this here because I want to have shadow when is open, but you have to create the xml file.
    android:background="@color/WHITE">

    <android.support.design.widget.CollapsingToolbarLayout
        android:id="@+id/collapsing_toolbar_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:collapsedTitleTextAppearance="@style/TextAppearance.AppCompat.Widget.ActionBar.Title.Inverse"
        app:expandedTitleMarginStart="72dp"
        app:expandedTitleTextAppearance="@style/TextAppearance.AppCompat.Widget.ActionBar.Title.Inverse"
        app:layout_scrollFlags="scroll|exitUntilCollapsed"> //HERE you should take a look what you want your collapse bar do.

        <Here you put the content for you collapse bar, like a ImageView>

        <android.support.v7.widget.Toolbar //This is the size of your fixed bar when you collapse, even here you can put a back button, for example
            android:id="@+id/app_bar"
            android:layout_width="match_parent"
            android:layout_height="40dp"
            app:layout_collapseMode="pin" />
    </android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>

<android.support.v4.widget.SwipeRefreshLayout
    android:id="@+id/main_home_list_swipe"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior" >

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

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

Obs: the comments will give errors if you put on a xml file. Is on propose so you will remember to read hahahah

Answer 2

Try this:- I also want this kind of animation on custom view and i have achieved it this way.

public class TestActivity extends AppCompatActivity {
    private static final int HIDE_THRESHOLD = 20;
    //this is you custom layout it is any thing.
    LinearLayout customLayout;
    private int scrolledDistance = 0;
    private boolean controlsVisible = true;
    private RecyclerView recyclerView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.your_layout);

        recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
        recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
                super.onScrollStateChanged(recyclerView, newState);
            }

            @Override
            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                scrolledDistance = dy;
                if (scrolledDistance > HIDE_THRESHOLD && controlsVisible) {
                    hideViews();
                    controlsVisible = false;
                } else if (scrolledDistance < -HIDE_THRESHOLD && !controlsVisible) {
                    showViews();
                    controlsVisible = true;
                }
            }
        });
    }

    private void hideViews() {
        customLayout.animate().translationY(-customLayout.getHeight()).setInterpolator(new AccelerateInterpolator(2));
    }

    private void showViews() {
        customLayout.animate().translationY(0).setInterpolator(new DecelerateInterpolator(2));
    }
}

Edit - 1 for ScrollView try this listener

scrollView.getViewTreeObserver().addOnScrollChangedListener(new ViewTreeObserver.OnScrollChangedListener() {
            @Override
            public void onScrollChanged() {
                if (scrolledDistance > HIDE_THRESHOLD && controlsVisible) {
                    hideViews();
                    controlsVisible = false;
                    scrolledDistance = 0;
                } else if (scrolledDistance < -HIDE_THRESHOLD && !controlsVisible) {
                    showViews();
                    controlsVisible = true;
                    scrolledDistance = 0;
                }
            }
        });

Hope it also helps you...