Develop Reference

Scroll lag in coordinate layout with viewpager

When switching pages in viewpager under appbarlayout the scroll does not work properly. Since the app:layout_scrollFlags="scroll" is used the appbarlayout should scroll smoothly out of screen when viewpager below is scrolled.
Check the video (after 12 seconds) https://www.youtube.com/watch?v=_gY-7SiDiFs
Here is a gif of the issue https://imgur.com/a/xHvDRhJ
Any help is appreciated.
Thanks.
Here is the layout
<android.support.design.widget.CoordinatorLayout
android:id="#+id/detail_main_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<android.support.design.widget.AppBarLayout
android:id="#+id/appbarlayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fitsSystemWindows="true"
app:elevation="0dp">
<android.support.design.widget.CollapsingToolbarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_scrollFlags="scroll">
<FrameLayout
android:id="#+id/detail_thumbnail_root_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#android:color/black"
android:clickable="true"
android:focusable="true"
android:foreground="?attr/selectableItemBackground"
app:layout_collapseMode="parallax">
</FrameLayout>
</android.support.design.widget.CollapsingToolbarLayout>
<RelativeLayout
android:id="#+id/fdsafsda123"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="?android:windowBackground"
app:layout_scrollFlags="scroll">
</RelativeLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
<android.support.design.widget.TabLayout
android:id="#+id/tablayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom|center"
android:background="#color/transparent_background_color"
app:tabBackground="#drawable/tab_selector"
app:tabGravity="center"
app:tabIndicatorHeight="0dp">
</android.support.design.widget.TabLayout>
</android.support.design.widget.CoordinatorLayout>

You should be able to hide the CollapsingToolbarLayout by adding another flag like this:
app:layout_scrollFlags="scroll|snap"
And to hide RelativeLayout, you can try this:
app:layout_scrollFlags="scroll|enterAlways"
And you'll need this to pin your view:
app:layout_collapseMode="pin"
Only scroll flag might not be enough.

Viewpager inside CoordinatorLayout not scrolling the Collapsing toolbar

I am trying to implement the parallax effect with for my layout.
It works, however I need one more thing.
Here is my code
<?xml version="1.0" encoding="utf-8"?>
<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/coordinator_layout_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<android.support.design.widget.AppBarLayout
android:id="#+id/app_bar_layout_main"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="?attr/colorPrimary"
android:fitsSystemWindows="true"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.design.widget.CollapsingToolbarLayout
android:id="#+id/collapsing_toolbar_main"
android:layout_width="match_parent"
android:layout_height="#dimen/height_toolbar_header_experiment_result"
app:contentScrim="?attr/colorPrimary"
app:layout_scrollFlags="scroll|exitUntilCollapsed|snap"
app:titleEnabled="false">
<ImageView
android:id="#+id/image_view_tab_header"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/experiment_result_header"
android:fitsSystemWindows="true"
android:scaleType="centerCrop"
app:layout_collapseMode="parallax"/>
<View
android:layout_width="match_parent"
android:layout_height="match_parent"
android:alpha="0.3"
android:background="#android:color/black"
android:fitsSystemWindows="true"/>
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar_tab_layout"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:layout_gravity="top"
android:layout_marginBottom="?actionBarSize"
app:layout_collapseMode="pin"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"/>
<android.support.design.widget.TabLayout
android:id="#+id/tab_layout_main"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
app:tabIndicatorColor="#android:color/white"
app:tabSelectedTextColor="#android:color/white"
app:tabTextColor="#color/whitesmoke"/>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/view_pager_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"/>
</android.support.design.widget.CoordinatorLayout>
This works fine, however I am only able to scroll/collapse toolber while swiping the header ImageView (image_view_tab_header). When I try to swipe up inside the ViewPager it doesn't collapse toolbar. Only when I try to swipe up inside the header itself.
How can I enable collapsing of toolbar when swiping inside the viewpager ?
Thanks

Try the following by including ViewPager inside NestedScrollView
<android.support.v4.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<android.support.v4.view.ViewPager
android:id="#+id/view_pager_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"/>
</android.support.v4.widget.NestedScrollView>

AppBarLayout not collapsing during programmatically scroll

I have a ViewPager with Fragments which containe a RecyclerViews. A CollapsingTollbarLayout is above the ViewPager. Everythings works fine except during a programmatically scroll on the RecyclerView. Then the AppBarLayout or CollapsingToolbarLayout doesn't responde.
Here is my base layout xml:
<?xml version="1.0" encoding="utf-8"?>
<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/coordinatorLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<android.support.design.widget.AppBarLayout
android:id="#+id/appBarLayout"
android:layout_width="match_parent"
android:layout_height="256dp"
android:fitsSystemWindows="true"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:layout_behavior="de.wackernagel.playball.ui.FlingBehaviour">
<android.support.design.widget.CollapsingToolbarLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
android:id="#+id/collapsingToolbarLayout"
app:contentScrim="?attr/colorPrimary"
app:titleEnabled="false"
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<ImageView
android:contentDescription="#null"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scaleType="centerCrop"
android:src="#drawable/showdown"
app:layout_collapseMode="parallax"/>
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="#dimen/doubleActionBarSize"
android:minHeight="?attr/actionBarSize"
android:gravity="top"
app:titleMarginTop="14dp"
app:layout_collapseMode="pin"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"/>
<android.support.design.widget.TabLayout
android:id="#+id/tabLayout"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="#android:color/transparent"
android:layout_gravity="bottom"
app:tabTextColor="#BEFFFFFF"
app:tabSelectedTextColor="#FFFFFFFF"
app:tabContentStart="#dimen/keyline_2"
app:tabMode="scrollable" />
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/viewPager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"/>
My goal is it to collapse the CollapsingToolbarLayout during a programmatically scroll like a normal touch scroll.
I do this by
Activity get Fragment at current viewpager position
Fragment get LayoutManager from RecyclerView
LayoutManager scrollToPosition x
The scrolling behavior works on RecyclerView but the CollapsingToolbarLayout doesn't responde.
EDIT
Here is the layout of my fragments:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<de.wackernagel.playball.views.EmptyAwareRecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="8dp" />
<TextView
android:id="#android:id/empty"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"/>

It is quite easy to solve this problem, it comes from the fact, that getNestedScrollingParentForType(type) in NestedScrollingChildHelper#dispatchNestedScroll returns null (support lib version = 27.0.2) for the non-touch scroll, so scrolling is not dispatched. Thus, one should do the following before scrolling programmatically:
if (!recyclerView.hasNestedScrollingParent(ViewCompat.TYPE_NON_TOUCH)) {
recyclerView.startNestedScroll(View.SCROLL_AXIS_VERTICAL, ViewCompat.TYPE_NON_TOUCH);
}

I was having this same problem, the AppBarLayout wouldn't collapse when the NestedScrollView was programmatically scrolled to the bottom. This resulted in Android miscalculating the bottom of the NestedScrollView when the AppBarLayout was expanded. When it was collapsed, it would scroll to the bottom correctly, but when it was expanded, it would come short of scrolling to the bottom by an amount equal to the height of the AppBarLayout. I found a simple fix for this by setting setExpanded to false immediately before attempting to scroll.
//scroll to the end of NestedScrollView
AppBarLayout appBarLayout = findViewById(R.id.app_bar_layout);
appBarLayout.setExpanded(false, true);
scrollView.post(() -> scrollView.fullScroll(View.FOCUS_DOWN));
...or if not using lambda expressions (i.e < Java 8)
//scroll to the end of NestedScrollView
AppBarLayout appBarLayout = findViewById(R.id.app_bar_layout);
appBarLayout.setExpanded(false, true);
scrollView.post(new Runnable() {
#Override
public void run() {
scrollView.fullScroll(View.FOCUS_DOWN);
}
});

<android.support.v4.view.ViewPager
android:id="#+id/htab_viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
<android.support.design.widget.AppBarLayout
android:id="#+id/htab_appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fitsSystemWindows="true"
app:layout_behavior="example.com.final.TabParallax.FlingBehavior"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.design.widget.CollapsingToolbarLayout
android:id="#+id/htab_collapse_toolbar"
android:layout_width="match_parent"
android:layout_height="360dp"
android:fitsSystemWindows="true"
app:contentScrim="?attr/colorPrimary"
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:padding="0dp">
<ImageView
android:id="#+id/htab_header"
android:layout_width="match_parent"
android:layout_height="359dp"
android:background="#drawable/channel"
android:fitsSystemWindows="true"
android:scaleType="centerCrop"
app:layout_collapseMode="parallax" />
</FrameLayout>
</android.support.design.widget.CollapsingToolbarLayout>
<android.support.design.widget.TabLayout
android:id="#+id/htab_tabs"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="#color/colorAccent1"
android:fitsSystemWindows="true"
android:gravity="bottom"
app:tabGravity="center"
app:tabIndicatorColor="#android:color/white"
app:tabMode="scrollable"
app:tabSelectedTextColor="#android:color/white"
app:tabTextColor="#android:color/white"
/>
</android.support.design.widget.AppBarLayout>

CollapsingToolbarLayout doesn't work well with NestedScrollView

I made an activity where image should collapse with toolbar and only text below would be visible. But When Toolbar being collapsed, there shows up a large gap between Toolbar and NestedScrollView
<android.support.design.widget.CoordinatorLayout xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/coordinatorLayout"
android:layout_width="match_parent"
android:background="#color/white"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="#+id/appBarLayout"
android:layout_width="match_parent"
app:elevation="5dp"
app:layout_collapseMode="pin"
android:fitsSystemWindows="true"
android:layout_height="wrap_content">
<android.support.design.widget.CollapsingToolbarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:toolbarId="#+id/toolbar"
android:id="#+id/collapsing"
android:fitsSystemWindows="true"
app:contentScrim="?attr/colorPrimary"
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<com.noframe.farmisagronom.util.ResizibleImageView
android:id="#+id/image_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_scrollFlags="scroll|enterAlwaysCollapsed"
android:minHeight="100dp"
android:maxHeight="400dp"
android:fitsSystemWindows="true"
app:layout_collapseMode="parallax"
app:layout_collapseParallaxMultiplier="0.5"
android:scaleType="centerCrop"/>
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:popupTheme="#style/ThemeOverlay.AppCompat.Light"
android:minHeight="?attr/actionBarSize"
app:layout_collapseMode="pin"
/>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v4.widget.NestedScrollView
android:id="#+id/nesteview"
app:layout_anchorGravity="top"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
.....
</android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>
And this activity looks really good.
But when i scroll up the NestedScrollView this goes out of control.
This little space between toolbar and text is getting on my nerves.
note that if there is large text in NestedScrollView problem won't show up, but if NestedScrollView + collapsed tool bar doesn't take all phone screen, then there is a gap between them.

Adding:
android:layout_gravity="fill_vertical"
to the NestedScrollView worked for me.

Viewpager not appearing when using CollapsingToolbarLayout

I've been playing around with the Design Support Library and have come across a little problem that I hope someone can help me out with.
I'm using a CollapsingToolbar which contain an ImageView which collapses in parralax. In the CollapsingToolbar, I alse have a TabLayout which is supposed to scroll my ViewPager. My issue is that the ViewPager doesn't appear. The issue seems to arise only when I set my ViewPager layout_height to match_parent or wrap_content. If I set it to 600dp, then the problem is gone but then the view ends up being a fixed length which isn't very nice.
Any help would be grealty appreciated!
Here's my XML
<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/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="#dimen/detail_backdrop_height"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar"
android:fitsSystemWindows="true"
>
<android.support.design.widget.CollapsingToolbarLayout
android:id="#+id/collapsing_toolbar"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_scrollFlags="scroll|exitUntilCollapsed"
android:fitsSystemWindows="true"
app:contentScrim="?attr/colorPrimary"
>
<ImageView
android:id="#+id/backdrop"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
app:layout_collapseMode="parallax"
android:src="#drawable/stock_image"/>
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"
android:layout_gravity="top"
/>
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"/>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v4.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/white"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
/>
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>

You should remove the NestedScrollView and LinearLayout levels between your CoordinatorLayout and ViewPager:
<android.support.design.widget.CoordinatorLayout>
<android.support.design.widget.AppBarLayout>
...
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/white"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>
The view with app:layout_behavior="#string/appbar_scrolling_view_behavior must be a direct child of CoordinatorLayout to be positioned correctly in relation to the AppBarLayout.