AppBarLayout hiding toolbar on scroll behavior, switching fragments

AppBarLayout hiding toolbar on scroll behavior, switching fragments - android

I've implemented a CoordinatorLayout and wrapped my Toolbar inside an AppBarLayout so that the toolbar hides itself when scrolling. Most of the app consists of Fragments that are swapped in and out of the #id/container FrameLayout as seen below. Some of the Fragments are just RecyclerViews, while others are other layouts. I've added app:layout_behavior="#string/appbar_scrolling_view_behavior" to the #id/container FrameLayout. Heres my main layout:
<DrawerLayout>
<RelativeLayout
android:id="#+id/mainRelativeLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<android.support.design.widget.CoordinatorLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
>
<android.support.design.widget.AppBarLayout
android:id="#+id/appBarLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
>
<Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:elevation="5dp"
app:layout_scrollFlags="scroll|enterAlways"
>
</Toolbar>
</android.support.design.widget.AppBarLayout>
<FrameLayout
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
/>
</android.support.design.widget.CoordinatorLayout>
</RelativeLayout>
<!-- ignore -->
<drawercontents>
</DrawerLayout>
Now, the Toolbar hides itself when scrolling on Fragments with a RecyclerView.
The issue is, when switching to another fragment that doesnt have a RecyclerView, it will mess up that fragments layout. For example, if I scroll down on a fragment that containers a RecyclerView, the Toolbar will hide itself (like it should). Then, if I switch to the other fragment without the RecyclerView, the toolbar will still be hidden, and the layout will expand into that extra space. If I start back at a fragment with a RecyclerView and dont scroll (so the Toolbar stays visible), and then switch to another fragment, the content is now pushed down off the screen because of the Toolbar.
Heres a screenshot of the issue: http://prnt.sc/a7majo
I also tried disabling the scroll behavior in that fragment using the following code:
Toolbar mToolbar = (Toolbar) getActivity().findViewById(R.id.toolbar);
AppBarLayout.LayoutParams toolbarLayoutParams = (AppBarLayout.LayoutParams) mToolbar.getLayoutParams();
toolbarLayoutParams.setScrollFlags(0);
mToolbar.setLayoutParams(toolbarLayoutParams);
AppBarLayout appBarLayout = (AppBarLayout) getActivity().findViewById(R.id.appBarLayout);
CoordinatorLayout.LayoutParams appBarLayoutParams = (CoordinatorLayout.LayoutParams) appBarLayout.getLayoutParams();
appBarLayoutParams.setBehavior(null);
appBarLayout.setLayoutParams(appBarLayoutParams);
This doesnt work either an produces the odd result pictured at the bottom here: http://prnt.sc/a7mapg
So whats the workaround for this? I've seen a few other questions that were similar to this but the answers given did not seem to work for my situation. Thanks in advance!

protected void setScrollingEnabled(boolean isEnabled) {
AppBarLayout.LayoutParams params = (AppBarLayout.LayoutParams) toolbar.getLayoutParams();
params.setScrollFlags(isEnabled ? (AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL | AppBarLayout.LayoutParams.SCROLL_FLAG_ENTER_ALWAYS) : 0);
}

Related

Scrollable Recycler view and view pager

I have a screen where i need to display a toolbar at the top, a slideshow below the toolbar and a recyclerview below the slideshow.
For displaying the slideshow I am using a viewPager which slides images horizontally.
The problem I am currently facing is that when the recyclerview is scrolled the viewPager needs to scroll with it and the toolbar should stay pinned.
I tried putting the viewPager and the recyclerview inside a nested Scroll but since a nested scroll requires a single child i had to put both the viewpager and recyclerview inside a linear layout because of which the scrolling behaviour of the recyclerview went for a toss ( i am monitoring the recyclerview scroll so i can load more results when it reaches the bottom ).

You can solve this problem by using CoordinatorLayout, AppBarLayout, and CollapsingToolbarLayout. You put your Toolbar and ViewPager in the CollapsingToolbarLayout, and you use the RecyclerView as the scrolling sibling to the AppBarLayout so that it can correctly collapse the ViewPager.
Here's some example XML I used to achieve what I think you described:
<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:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.design.widget.CollapsingToolbarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<android.support.v4.view.ViewPager
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_marginTop="?attr/actionBarSize"/>
<android.support.v7.widget.Toolbar
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_collapseMode="pin"/>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
app:layoutManager="LinearLayoutManager"/>
</android.support.design.widget.CoordinatorLayout>
The only tricky bit is that the <Toolbar> tag has to come after the <ViewPager> tag, since they're both inside a view that derives from FrameLayout. Normally, this would mean that the toolbar obscures the top portion of the viewpager, but the viewpager's marginTop attribute stops that from happening.

CoordinatorLayout content child overlaps BottomNavigationView

I'm trying to use a CoordinatorLayout with a BottomNavigationView, an AppBarLayout, and a ViewPager. Here is my layout:
<?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:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context=".MainActivity">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fitsSystemWindows="true"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:layout_scrollFlags="enterAlways|scroll"
app:popupTheme="#style/AppTheme.PopupOverlay"/>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"/>
<android.support.design.widget.BottomNavigationView
android:id="#+id/navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:background="?android:attr/windowBackground"
app:itemIconTint="?colorPrimaryDark"
app:itemTextColor="?colorPrimaryDark"
app:menu="#menu/navigation"/>
</android.support.design.widget.CoordinatorLayout>
The problem is that the CoordinatorLayout places the ViewPager to extend to the bottom of the screen, so the bottom is obscured by the BottomNavigationView, like this:
This happens even though the CoordinatorLayout itself doesn't extend down so far:
I've tried adding app:layout_insetEdge="bottom" to the BottomNavigationView and app:layout_dodgeInsetEdges="bottom" to the ViewPager, but that has a different problem: it shifts the bottom of the ViewPager up, but it keeps the same height, so the top is now chopped off:
I tried two other experiments. First, I tried removing the BottomNavigationView from the CoordinatorLayout and making them siblings under a vertical LinearLayout. Second, I put the ViewPager and BottomNavigationView together under a LinearLayout, hoping they would layout out correctly. Neither helped: in the first case, the CoordinatorLayout still sized the ViewPager with respect to the entire screen, either hiding part of it behind the BottomNavigationView or chopping off the top. In the second case, the user needs to scroll to see the BottomNavigationView.
How do I get the layout right?
P.S. When I tried the layout suggested by #Anoop S S (putting the CoordinatorLayout and the BottomNavigationView as siblings under a RelativeLayout), I get the following (with the ViewPager still extending down behind the BottomNavigationView):
As before, the CoordinatorView itself only extends down to the top of the BottomNavigationView.

I came up with a different approach (not battle tested yet though):
I subclassed AppBarLayout.ScrollingViewBehavior to adjust the bottom margin of the content view based on the height of the BottomNavigationView (if present). This way it should be future proof (hopefully) if the height of the BottomNavigationView changes for any reason.
The subclass (Kotlin):
class ScrollingViewWithBottomNavigationBehavior(context: Context, attrs: AttributeSet) : AppBarLayout.ScrollingViewBehavior(context, attrs) {
// We add a bottom margin to avoid the bottom navigation bar
private var bottomMargin = 0
override fun layoutDependsOn(parent: CoordinatorLayout, child: View, dependency: View): Boolean {
return super.layoutDependsOn(parent, child, dependency) || dependency is BottomNavigationView
}
override fun onDependentViewChanged(parent: CoordinatorLayout, child: View, dependency: View): Boolean {
val result = super.onDependentViewChanged(parent, child, dependency)
if(dependency is BottomNavigationView && dependency.height != bottomMargin) {
bottomMargin = dependency.height
val layout = child.layoutParams as CoordinatorLayout.LayoutParams
layout.bottomMargin = bottomMargin
child.requestLayout()
return true
} else {
return result
}
}
}
And then in the layout XML you put:
app:layout_behavior=".ScrollingViewWithBottomNavigationBehavior"
instead of
app:layout_behavior="#string/appbar_scrolling_view_behavior"

Basically what you have to do is create a Relativelayout as parent and put BottomNavigationView and CoordinatorLayout as children. Then align BottomNavigationView at the bottom and set CoordinatorLayout above that. Please try the below code. It might have few attribute erros, because I wrote it here itself. And sorry for the messed up indentation.
<?xml version="1.0" encoding="utf-8"?>
<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"
tools:context=".MainActivity">
<android.support.design.widget.CoordinatorLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="#+id/navigation"
>
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fitsSystemWindows="true"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:layout_scrollFlags="enterAlways|scroll"
app:popupTheme="#style/AppTheme.PopupOverlay"/>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"/>
</android.support.design.widget.CoordinatorLayout>
<android.support.design.widget.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="?colorPrimaryDark"
app:itemTextColor="?colorPrimaryDark"
app:menu="#menu/navigation"/>
</RelativeLayout>

This is caused by app:layout_behavior="#string/appbar_scrolling_view_behavior" in your ViewPager. If you remove this line, you will see now it fits the CoordinatorLayout container (unfortunately, this includes now being underneath the Toolbar).
I found it helped to treat CoordinatorLayout as just a FrameLayout, with a few extra tricks. The app:layout_behavior attribute above is necessary to allow the toolbar to appear to scroll in and out... in reality, the layout is doing this by having the view linked to the collapsing toolbar (in your case, your ViewPager) be exactly a toolbar's height larger than the bounds. Scrolling up brings the view up to the bottom within the bounds, and pushes the toolbar up extending beyond the bounds. Scrolling down, vice versa.
Now, onto the BottomNavigationView! If, as I did, you want the BottomNavigationView visible the whole time, then move it outside the CoordinatorLayout, as Anoop said. Use CoordinatorLayout only for things that need to coordinate, everything else outside. I happened to use a ConstraintLayout for my parent view (you could use RelativeLayout or whatever works for you though). With ConstraintLayout, for you it would look like this:
<android.support.constraint.ConstraintLayout
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">
<android.support.design.widget.CoordinatorLayout
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="#id/navigation"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:context=".MainActivity">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fitsSystemWindows="true"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:layout_scrollFlags="enterAlways|scroll"
app:popupTheme="#style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>
<android.support.design.widget.BottomNavigationView
android:id="#+id/navigation"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:background="?android:attr/windowBackground"
app:itemIconTint="?colorPrimaryDark"
app:itemTextColor="?colorPrimaryDark"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:menu="#menu/navigation" />
</android.support.constraint.ConstraintLayout>
In Android Studio design view, you're still going to see the ViewPager appear to be larger than the container (probably looks like it's behind the Bottom Nav still). But that's ok, when you get to the bottom of the ViewPager's content, it will show (i.e. won't be behind the bottom navigation). This quirk in the design view is just the way the CoordinatorLayout makes the toolbar show/hide, as mentioned earlier.

I had a similar problem with a layout very close to OP's and a ViewPager with 3 pages but only page 2 and 3 which should be affected by appbar_scrolling_view_behavior.
After struggling for hours exploring dead-end possible solutions (layout_dodgeInsetEdges, Window insets, attempting to modify ViewPager's page measured size, android:clipChildren, fitSystemWindows, ...), I finally found an easy solution detailed below.
As Vin Norman explained, ViewPager overlapping BottomNavigation is entirely caused by appbar_scrolling_view_behavior set on the ViewPager. AppBarLayout will just make fullscreen the sibling that has appbar_scrolling_view_behavior. That's how it works.
If you only need this behavior on certain ViewPager pages, there is a simple fix than you can apply on the ViewPager's OnPageChangeListener to dynamically change the Behavior and add/remove required padding:
public class MyOnPageChangeListener extends ViewPager.SimpleOnPageChangeListener {
#Override
public void onPageSelected(int position) {
...
CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) _viewPager.getLayoutParams();
if(position == 0) {
params.setBehavior(null);
params.setMargins(params.leftMargin, _appBarLayoutViewPagerMarginTopPx,
params.rightMargin, _appBarLayoutViewPagerMarginBottomPx);
} else {
params.setBehavior(_appBarLayoutViewPagerBehavior);
params.setMargins(params.leftMargin, 0, params.rightMargin, 0);
}
_viewPager.requestLayout();
}
}
For page at position 0 (the one we want the ViewPager to extend exactly below the Toolbar and above the BottomNavigationView), it removes the behavior and adds top and bottom padding, respectively _appBarLayoutViewPagerMarginTopPx and _appBarLayoutViewPagerMarginBottomPx that are constants easy to compute beforehand (respectively the value in pixel for R.attr.actionbarSize and the height for the NavigationBottomView. Usually both are 56dp)
For all other pages needing appbar_scrolling_view_behavior we restore the associated scrolling behavior (stored beforehand in _appBarLayoutViewPagerBehavior) and remove top and bottom padding.
I tested this solution and it works fine without caveat.

In case anyone is still searching for a solution of this problem:
Cause of the problem is that CoordinatorLayout is not calculating correctly size of AppBarLayout because it has Toolbar with app:layout_scrollFlags="enterAlways|scroll" setting. It thinks that Toolbar will hide when scrolling so it leaves all available space to ViewPager, but actually what happens is that toolbar shows so ViewPager moves down, behind NavigationBar.
Easiest way to solve this is just to add android:minHeight="?attr/actionBarSize" (or whatever toolbar height you are using) to AppBarLayout. This way CoordinatorLayout will know properly how much space it needs to leave for ViewPager.

If it still matters to someone:
In the answer of Anoop SS above, trying replacing the RelativeLayout with LinearLayout. Also set layout_height of CoordinatorLayout to 0dp and set layout_weight to 1.
I had almost the same problem....just that i wanted to have a static AdView at the bottom instead of the BottomNavigationView. Trying Anoop SS suggestions, at first, I got the same behaviour as OP: ViewPager extended behind the AdView. But then I did what I suggested about and everything worked fine.
Android layouts behave in weird manner or may be it is the lack of good documentation or the lack of knowledge on our part....but making a layout is just too annoying most of the time.

If you are using Androidx try this
<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"
android:fitsSystemWindows="true"
tools:context=".MainActivity">
<androidx.coordinatorlayout.widget.CoordinatorLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
android:layout_above="#+id/bottomNavView">
<com.google.android.material.appbar.AppBarLayout
android:id="#+id/appBarLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
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>
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<fragment
android:id="#+id/nav_host_fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:defaultNavHost="true"
app:navGraph="#navigation/mobile_navigation" />
</FrameLayout>
</androidx.coordinatorlayout.widget.CoordinatorLayout>
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/bottomNavView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:background="?android:attr/windowBackground"
app:menu="#menu/bottom_nav" />

Hide top and bottom toolbars when using CoordinatorLayout

I have managed to figure out how to add a bottom toolbar to CoordinatorLayout, but can't seem to figure out how to hide the bottom RelativeLayout.
If I add #string/appbar_scrolling_view_behavior to the bottom RelativeLayout, the bottom bar appears when the user scroll upwards. The desired effect is both top and bottom bars appear when the user scrolls upwards. Any ideas how I would approach this? A universal bottom bar (for simple actions) across all the tab is needed since my ViewPager contain complicated code from other libraries.
A floating action button is not preferable since it hides the collection of actions inside a button that requires the user to tap and expand. Here below is my xml layout for managing the tabs and pager:
<?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="wrap_content"
xmlns:ads="http://schemas.android.com/tools">
<android.support.design.widget.AppBarLayout
android:id="#+id/app_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.design.widget.CollapsingToolbarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_scrollFlags="scroll|enterAlways">
<android.support.design.widget.TabLayout
android:id="#+id/tab_layout"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="#1378BB"
app:layout_scrollFlags="scroll|enterAlways"/>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/pager"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_scrollFlags="scroll|enterAlwaysCollapsed"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
>
<android.support.v7.widget.Toolbar
android:id="#+id/tabs"
android:background="#3202c4"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_scrollFlags="scroll|enterAlwaysCollapsed"
android:layout_alignParentBottom="true"
android:layout_marginBottom="100dp"
/>
</RelativeLayout>
</android.support.design.widget.CoordinatorLayout>
Any thoughts or ideas? I tried placing the toolbar inside CollapsingToolbarLayout and use layout_alignParentBottom="true", but that only anchored the toolbar to AppBarLayout and not the entire CoordinatorLayout
Only if I could get #string/appbar_scrolling_view_behavior to trigger the other way around for the bottom RelativeLayout (make bar appear when scrolling in the opposite direction it was intended to trigger)

You need to add custom CoordinatorLayout.Behavior to the bottom Toolbar. Toolbar must be a direct child of CoordinatorLayout.
Mark it with:
app:layout_behavior="{name_of_the_class_of_behavior}"
app:layout_scrollFlags="scroll|enterAlways"
In custom behaviour override to methods:
#Override
public boolean layoutDependsOn(CoordinatorLayout parent, View fab, View dependency) {
return dependency instanceof AppBarLayout;
}
and the second one is:
public boolean onDependentViewChanged(CoordinatorLayout parent, View fab, View dependency)
where you control the visibility of the target view. Basically what is needed is to measure what part of AppBarLayout is shown, translate it and set it to your view accordingly:
CoordinatorLayout.LayoutParams lp = (CoordinatorLayout.LayoutParams) view.getLayoutParams();
int viewBottomMargin = lp.bottomMargin;
int distanceToScroll = view.getHeight() + viewBottomMargin;
float ratio = dependency.getY() / toolbarHeight;
view.setTranslationY(-distanceToScroll * ratio);
More about it here

Android - Frame layout height not matching with coordinator layout

I have a problem with my FrameLayout (Container in Drawer Layout). The height of the FrameLayout exceeds the screen height (below the android default menu buttons at bottom).
<android.support.design.widget.CoordinatorLayout
android:id="#+id/main_content"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<android.support.design.widget.AppBarLayout
android:id="#+id/navContainer"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minHeight="?attr/actionBarSize"
app:layout_scrollFlags="scroll|enterAlways" />
</android.support.design.widget.AppBarLayout>
<FrameLayout
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>

My first attempt was to set a android:layout_marginBottom="?attr/actionBarSize" at the FrameLayout. This solved the solution for non-scrollable views having a "fixed" height in terms of no vertically scrollable content (like a usual RelativeLayout with match_parent height). Aligning a component to the parent bottom (android:layout_alignParentBottom="true") results in a still visible element. In Android Studio's Previewer the no exceeding of the height is visible.
However, this marginBotton-fix introduces a new problem for fragments whose root view is scrollable (like a RecyclerView). For these views when scrolling down the bottom margin will become visible in a white bar (in case white is the background color). This seams reasonable, as for those views the nested scrolling feature will slide out the toolbar
tl;dr I worked around that issue by applying the the ?attr/actionBarSize as bottom margin to non-scrollable fragments that are shown inside the Framelayout. Prior to that I set the height of the toolbar to be ?attr/actionBarSize.
Activity layout:
<android.support.design.widget.AppBarLayout
android:id="#+id/navContainer"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:layout_scrollFlags="scroll|enterAlways" />
</android.support.design.widget.AppBarLayout>
<FrameLayout
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
/>
</android.support.design.widget.CoordinatorLayout>
Fragment layout:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginBottom="?attr/actionBarSize"
android:orientation="vertical">
<!-- Further stuff here -->
<TextView android:id="#+id/label"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
/>
</LinearLayout>
The only downside I faced right now is the white space to be shown in Android Studio's Previewer while creating the fragment layout.

If you use different Fragments inside your CoordinatorLayout you will face the problem, that some Fragments have scrollable content and some should not scroll. Your Toolbar has the scrolling flags "scroll|enterAlways", which is ok for the former layouts, but not ok for the latter. My solution is a custom AppBarLayout.Behavior which switches the scrolling flags dependant on the custom tag (contentShouldNotScrollTag). Set this tag for the layouts, which should not scroll like this:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:tag="#string/contentShouldNotScrollTag">
<!-- my non-scrollable Fragment layout -->
</FrameLayout>
As the result, the height of this Fragment will not exceed the screen's height. Here is the custom behavior class for the AppBarLayout:
public class MyScrollBehavior extends AppBarLayout.Behavior {
private View content;
public MyScrollBehavior(Context context, AttributeSet attrs) {
super(context, attrs);
}
#Override
public boolean onMeasureChild(CoordinatorLayout parent, AppBarLayout appBarLayout, int parentWidthMeasureSpec, int widthUsed, int parentHeightMeasureSpec, int heightUsed) {
if(content == null) {
content = parent.findViewById(R.id.container);
}
if(content != null) {
boolean shouldNotScroll = content.findViewWithTag(parent.getContext().getString(R.string.contentShouldNotScrollTag)) != null;
Toolbar toolbar = (Toolbar) appBarLayout.findViewById(R.id.toolbar);
AppBarLayout.LayoutParams params =
(AppBarLayout.LayoutParams) toolbar.getLayoutParams();
if (shouldNotScroll) {
params.setScrollFlags(0);
appBarLayout.setExpanded(true, true);
} else {
params.setScrollFlags(AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL
| AppBarLayout.LayoutParams.SCROLL_FLAG_ENTER_ALWAYS);
}
}
return super.onMeasureChild(parent, appBarLayout, parentWidthMeasureSpec, widthUsed, parentHeightMeasureSpec, heightUsed);
}
}

CollapsingToolbarLayout | Scrolling and layout issues 2

Related Questions
CollapsingToolbarLayout | Scrolling and layout issues
Backgroud
I want to use 2 different fragments that will allow me to change the layout based on orientation and screen size
Header Image (Currently just an ImageView)
Scrollable content
Issues
The CollapsingToolbarLayout does not allow me to expand the Toolbar to see the full Header Image
It shows a majority of the image, but not all. Top is cut, but the bottom is visible.
The Toolbar is set to Pin but it is hidden when scrolling
Just the Header Image should disappear, but instead my whole Appbar gets hidden
When scrolling to view the Expanded Toolbar there is an empty view until the Expanded Toolbar reaches its max height.
After both the Expanded Toolbar and the Toolbar itself become hidden
The Up Arrow does not show up in the Toolbar
Code
Layout.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: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="wrap_content"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.design.widget.CollapsingToolbarLayout
android:id="#+id/collapsing_toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:contentScrim="?attr/colorPrimary"
app:expandedTitleMarginEnd="16dp"
app:expandedTitleMarginStart="48dp"
app:layout_scrollFlags="scroll|enterAlways">
<ImageView
android:id="#+id/header"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#drawable/download"
android:scaleType="centerCrop" />
<android.support.v7.widget.Toolbar
android:id="#+id/anim_toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:layout_collapseMode="pin" />
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v4.widget.NestedScrollView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_below="#+id/anim_toolbar"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<fragment
android:id="#+id/detail"
android:name="<package>.<fragment_name>"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>
OnCreate
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.test);
final Toolbar toolbar = (Toolbar) findViewById(R.id.anim_toolbar);
setSupportActionBar(toolbar);
CollapsingToolbarLayout collapsingToolbar = (CollapsingToolbarLayout) findViewById(R.id.collapsing_toolbar);
collapsingToolbar.setTitle("Avengers: Age of Ultron");
}
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Question 1
Add android:fitsSystemWindows="true" to your AppBarLayout, CollapsingToolbarLayout, and to your ImageView.
I'm guessing a part of your image is below the status bar (due to these lines being missing) which is why you can't see the top of the image.
Question 2
collapseMode="pin" only affects how the Toolbar reacts to collapsing (hence why it is called collapseMode and not scrollFlags).
In almost all cases when using CollapsingToolbarLayout, you should be using scroll|exitUntilCollapsed for your scrollFlags - this keeps the collapsed Toolbar visible even when you scroll downward.
Question 3
This is due to using scroll|enterAlways. Change your flags as per #2
Question 4
As mentioned in the answer to your related question, you need to call getSupportActionBar().setDisplayHomeAsUpEnabled(true); to show the Up button:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.test);
final Toolbar toolbar = (Toolbar) findViewById(R.id.anim_toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
CollapsingToolbarLayout collapsingToolbar =
(CollapsingToolbarLayout) findViewById(R.id.collapsing_toolbar);
collapsingToolbar.setTitle("Avengers: Age of Ultron");
}

Remove app:contentScrim="?attr/colorPrimary" from your layout XML in CollapsingToolBarLayout tag. It will show the back button in toolbar

Develop Reference

The Android operating system is a mobile operating system that was developed by Google (GOOGL?) to be primarily used for touchscreen devices, cell phones, and tablets.

AppBarLayout hiding toolbar on scroll behavior, switching fragments - android

protected void setScrollingEnabled(boolean isEnabled) { AppBarLayout.LayoutParams params = (AppBarLayout.LayoutParams) toolbar.getLayoutParams(); params.setScrollFlags(isEnabled ? (AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL | AppBarLayout.LayoutParams.SCROLL_FLAG_ENTER_ALWAYS) : 0); }

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CollapsingToolbarLayout | Scrolling and layout issues 2

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