Develop Reference

BottomNavigationView hidden by default after adding scroll behaviour

I have the following main layout and a recyclerview in my fragment. The problem i am facing is that the bottom navigation view is hidden by default and appears only when i scroll down the navigation view appears.
Before scrolling down
After scrolling down the bottomnavigationview appears
Another issue i am facing is that after scrolling down and changing the fragment the toolbar disappears
content_home.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context=".activity.HomeActivity"
tools:showIn="#layout/activity_home">
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:background="?android:attr/windowBackground"
app:itemIconTint="#drawable/nav_item_foreground"
app:itemTextColor="#drawable/nav_item_foreground"
app:layout_behavior="#string/hide_bottom_view_on_scroll_behavior"
app:menu="#menu/navigation" />
<FrameLayout
android:id="#+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="#+id/navigation" />
</RelativeLayout>
This is the main activity layout
activity_home.xml
<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<com.google.android.material.appbar.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/appBar"
android:theme="#style/AppTheme.AppBarOverlay">
<androidx.appcompat.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="#style/AppTheme.PopupOverlay" />
</com.google.android.material.appbar.AppBarLayout>
<include
layout="#layout/content_home" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>

There is an issue in your content_home.xmlYou are using app:layout_behavior="#string/hide_bottom_view_on_scroll_behavior" in BottomNavigationView.
That's why it is happing.
Remove hide_bottom_view_on_scroll_behaviorfrom app:layout_behavior.

ViewPager extends over the bottom of the screen

I'm new to Android development and I'm facing the following issue.
This is the layout of my main activity:
<?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:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar_main"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:elevation="4dp"
app:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"
app:layout_scrollFlags="scroll|enterAlways">
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:tabIndicatorColor="#color/white"
app:tabTextColor="#color/selected_text"
app:tabSelectedTextColor="#color/white"/>
</android.support.v7.widget.Toolbar>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/main_pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"/>
</android.support.design.widget.CoordinatorLayout>
For each tab in the ViewPager I have a fragment, and this is the layout of one of them
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="#color/colorPrimary"
android:id="#+id/linear_layout"
tools:context=".fragments.Reviews">
<RatingBar
android:id="#+id/review_totalRating"
style="?android:attr/ratingBarStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:numStars="5"
android:stepSize=".5"
android:isIndicator="true"
android:progressTint="#color/golden"
android:layout_gravity="center"
android:paddingTop="10dp"
android:paddingBottom="5dp" />
<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:divider="#android:color/transparent"
android:dividerHeight="8dp"
android:paddingLeft="8dp"
android:paddingRight="8dp"
android:id="#+id/listView_reviews" />
</LinearLayout>
Then I populate my ListView with items whose layout is defined in another xml file. My problem is with the ViewPager layout_height: it is now set to match_parent, but the element extends over the bottom of the screen, with the result that the last element of the ListView is covered by the navigation buttons.
This is what I see in the design editor
ViewPager overflow
How can I make the element stop before the navigation buttons?

I faced this issue too. It's because of AppBarLayout behavior in CoordinatorLayout. By default when you create a project from a template it will set up layout with hiding Toolbar. You can run your example and check it - just swipe toolbar up and it will hide and ViewPager will move up and then correctly sticks to the bottom of the screen.
It's not a solution for some cases so you can disable this behavior by removing app:layout_scrollFlags attribute from your Toolbar. After this, the toolbar will become unhideable and the ViewPager will calculate own height correctly.

I solved using a LinearLayout as the only child of the CoordinatorLayout, so everything else becomes a children of the LinearLayout. It seems to me to be just a simple workaround, not a final solution, but now it works. This is now the layout of my main activity:
<?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: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.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar_main"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:elevation="4dp"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"
app:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:tabIndicatorColor="#color/orange_050"
app:tabSelectedTextColor="#color/orange_050"
app:tabTextColor="#color/orange_050"/>
</android.support.v7.widget.Toolbar>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/main_pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"/>
</LinearLayout>

Hiding view below toolbar in coordinator layout

I'm working on creating a layout that works as follows:
Toolbar at the top
Toolbar below top toolbar
RecyclerView
And when I scroll, I want to hide the toolbar in between top toolbar and recyclerView. My Layout is as follows:
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="SomeActivity">
<android.support.design.widget.AppBarLayout
android:id="#+id/app_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:elevation="4dp"
app:contentInsetLeft="0dp"
app:contentInsetStart="0dp"
app:popupTheme="#style/AppTheme.PopupOverlay"
app:layout_scrollFlags="scroll|enterAlways"/>
<android.support.v7.widget.Toolbar
android:layout_width="match_parent"
android:layout_height="50dp"
android:minHeight="0dp"
android:id="#+id/info_bar"
app:popupTheme="#style/AppTheme.PopupOverlay"
app:contentInsetLeft="0dp"
app:contentInsetStart="0dp"
app:layout_scrollFlags="scroll|enterAlways" />
</android.support.design.widget.AppBarLayout>
<android.support.v7.widget.RecyclerView
android:id="#+id/content_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"/>
With these changes, both the toolbars become hidden when scrolling.
I just need to hide the second toolbar.
EDIT : If I can't get this to work, I'll be attaching a scroll listener to my recyclerView and resolving this that way. But I was wondering if there is a cleaner solution with scroll behaviors

Moved the top toolbar out of the coordinatorlayout and thus resolved this issue.
(Thanks to a colleague)
<LinearLayout 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:orientation="vertical">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light" />
<android.support.design.widget.CoordinatorLayout
android:id="#+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_scrollFlags="scroll|enterAlways" />
</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.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="end|bottom"
android:layout_margin="#dimen/fab_margin"
android:src="#drawable/ic_done" />
</android.support.design.widget.CoordinatorLayout>

If I understood properly, then you might want to collapse hole collapseableToolbar when it is scrolled up, instead it is showing some (20dp) space between ToolBar and listItem. for me it took half of the day, and problem is just a boolean value in coordinatorLayout. Just change "fitsSystemWindows" value from true to false.
with this you can hide image of the collapseToolBar upon scrolling.
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="false"
tools:context="com.thedeveloperworldisyours.imagecollapsingtoolbarlayout.ScrollingActivity">

Recyclerview + viewpager, make toolbar collapse

I have a recyclerview inside a viewpager. I also have Tabs above that and a toolbar. I'd like to collapse those (or one of those I have to try it out) when I move the recyclerView down. Basically the same as here.
I'm having trouble to get this to work.
Here is what I have:
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="com.cedric.testdesign.MainActivity">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="#style/AppTheme.PopupOverlay" />
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
style="#style/MyCustomTabLayout"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"/>
</android.support.design.widget.AppBarLayout>
<com.signpetitions.cedric.signpetitions.components.MyFab
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:layout_margin="#dimen/fab_margin"
android:src="#android:drawable/ic_dialog_email" />
<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.CoordinatorLayout>
Inside the viewPager I have a fragment with a recycler view:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.RecyclerView
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/recyclerView"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />

I added this to the toolbar :
app:layout_scrollFlags="scroll|enterAlways"
Then it works. The issue though is that when the statusbar is transparent the text behind the toolbar is visible. So the statusbar has to have a color.

Position ViewPager within CoordinatorLayout

I have a ViewPager within a CoordinatorLayout:
<android.support.v4.view.ViewPager
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="fill_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
/>
It's a little faint in the picture, but the blue box is after the toolbar.
It puts the ViewPager after the ToolBar and TabBar, but the height extends too much. I want the height to fill the parent.
If I remove the layout behavior it works, but I don't know how much the marginTop should be (there's the ActionBar's height + TabBar's height).
<android.support.v4.view.ViewPager
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:layout_marginTop="150dp"
/>
I want to have the ViewPager be after the toolbar and extend to the end of the device.
This is the entire 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"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context=".MainView">
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="#dimen/appbar_padding_top"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="#style/AppTheme.PopupOverlay">
</android.support.v7.widget.Toolbar>
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="fill_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
/>
<android.support.design.widget.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="end|bottom"
android:layout_margin="#dimen/fab_margin"
android:src="#android:drawable/ic_dialog_email" />
</android.support.design.widget.CoordinatorLayout>

The behavior is because of your current configuration of the app:layout_scrollFlags. If you don't android to push the ViewPager down set it to an empty String app:layout_scrollFlags="". You can change its behavior afterwards if you need/have/want to.
you should wrap the AppBarLayout and the ViewPager in the CoordinatorLayour and add app:layout_behavior="#string/appbar_scrolling_view_behavior" to the ViewPager. That line does the trick. Avoid that the content of your ViewPager goes behind the Toolbar/TabLayout