How to enable or disable collapsing in CollapsibleToolbarLayout in android? - android-layout

Question

**Main Layout**:
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
android:orientation="vertical">
<android.support.design.widget.AppBarLayout
android:id="#+id/appBarLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#color/White">
<android.support.design.widget.CollapsingToolbarLayout
android:id="#+id/collapsing_toolbar"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:contentScrim="#color/white"
app:titleEnabled="false"
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<TextView
android:id="#+id/collapsing_title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:adjustViewBounds="true"
android:text="Journal Name, Volume No, Issue"
android:textSize="40sp"
android:textStyle="bold"
android:textColor="#color/black"
android:padding="30dp"
android:layout_marginTop="?attr/actionBarSize"
app:layout_collapseMode="parallax" />
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="#color/primary"
app:layout_collapseMode="pin" />
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<include layout="#layout/article_listing_content"/>
</android.support.design.widget.CoordinatorLayout>
**Layout**:article_listing_content
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<RelativeLayout
android:id="#+id/rv_container"
android:visibility="visible"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
android:id="#+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clipToPadding="false"
android:longClickable="true"
android:elevation="50dp"
android:scrollbars="vertical"/>
</RelativeLayout>
<RelativeLayout
android:id="#+id/error_msg_container"
android:visibility="gone"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/error_msg"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</RelativeLayout>
</RelativeLayout>
I want to disable the collapsing of the title field (collapsing_title - TextView inside CollapsingToolbarLayout) if there is not enough data in the recycler view. ie Collapsing should only happen if there is more data / scrolling is required, else collapsing should be disabled.

Answer 1

You can "disable" this collapsing behavior by modifying your CollapsingToolbarLayout's app:layout_scrollFlags attribute.
As a layout_ attribute, this is part of the parent's LayoutParams (i.e. AppBarLayout.LayoutParams). As expected, this class exposes the method setScrollFlags().
To disable collapsing:
CollapsingToolbarLayout collapsing =
(CollapsingToolbarLayout) findViewById(R.id.toolbar_layout);
AppBarLayout.LayoutParams params =
(AppBarLayout.LayoutParams) collapsing.getLayoutParams();
params.setScrollFlags(0);
collapsing.setLayoutParams(params);
To re-enable collapsing, simply replace the setScrollFlags() call with one that passes in your original flags:
params.setScrollFlags(AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL | AppBarLayout.LayoutParams.SCROLL_FLAG_EXIT_UNTIL_COLLAPSED);