Develop Reference

Android Layout: Horizontal Recyclerview inside a Vertical Recyclerview inside a Viewpager with Scroll Behaviors

This is the app I'm trying to build with all the elements mapped out below:
Everything works, however, I want the inner horizontal recyclerview not to capture any of the vertical scrolls. All vertical scrolls must go towards the outer vertical recyclerview, not the horizontal one, so that the vertical scroll would allow for the toolbar to exit out of view according to it's scrollFlag.
When I put my finger on the "StrawBerry Plant" part of the recyclerview and scroll up, it scroll out the toolbar:
If I put my finger on the horizontal scrollview and scroll up, it does not scroll out the toolbar at all.
The following is my xml layout code so far.
The Activity xml layout:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
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:id="#+id/fragment_container"
android:clipChildren="false">
<android.support.design.widget.CoordinatorLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/container"
>
<android.support.design.widget.AppBarLayout
android:id="#+id/appBarLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:minHeight="?attr/actionBarSize"
android:background="?attr/colorPrimary"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_scrollFlags="scroll|enterAlways">
</android.support.v7.widget.Toolbar>
<android.support.design.widget.TabLayout
android:id="#+id/sliding_tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="?attr/colorPrimary"
style="#style/CustomTabLayout"
/>
</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.CoordinatorLayout>
</FrameLayout>
The "Fruits" fragment xml layout (which is the code for the fragment - the fragment is labeled in the above picture):
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ProgressBar
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/progressBar"
android:visibility="gone"
android:layout_centerInParent="true"
android:indeterminate="true"/>
<!-- <android.support.v7.widget.RecyclerView-->
<com.example.simon.customshapes.VerticallyScrollRecyclerView
android:id="#+id/main_recyclerview"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</RelativeLayout>
I have used a custom class called VerticallyScrollRecyclerView which follows google example of handling touch events in a viewgroup. Its aim is to intercept and consume all the vertical scroll events so that it will scroll in / out the toolbar: http://developer.android.com/training/gestures/viewgroup.html
The code for VerticallyScrollRecyclerView is below:
public class VerticallyScrollRecyclerView extends RecyclerView {
public VerticallyScrollRecyclerView(Context context) {
super(context);
}
public VerticallyScrollRecyclerView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public VerticallyScrollRecyclerView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
ViewConfiguration vc = ViewConfiguration.get(this.getContext());
private int mTouchSlop = vc.getScaledTouchSlop();
private boolean mIsScrolling;
private float startY;
#Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
final int action = MotionEventCompat.getActionMasked(ev);
// Always handle the case of the touch gesture being complete.
if (action == MotionEvent.ACTION_CANCEL || action == MotionEvent.ACTION_UP) {
// Release the scroll.
mIsScrolling = false;
startY = ev.getY();
return super.onInterceptTouchEvent(ev); // Do not intercept touch event, let the child handle it
}
switch (action) {
case MotionEvent.ACTION_MOVE: {
Log.e("VRecView", "its moving");
if (mIsScrolling) {
// We're currently scrolling, so yes, intercept the
// touch event!
return true;
}
// If the user has dragged her finger horizontally more than
// the touch slop, start the scroll
// left as an exercise for the reader
final float yDiff = calculateDistanceY(ev.getY());
Log.e("yDiff ", ""+yDiff);
// Touch slop should be calculated using ViewConfiguration
// constants.
if (Math.abs(yDiff) > 5) {
// Start scrolling!
Log.e("Scroll", "we are scrolling vertically");
mIsScrolling = true;
return true;
}
break;
}
}
return super.onInterceptTouchEvent(ev);
}
private float calculateDistanceY(float endY) {
return startY - endY;
}
}
The "Favourite" layout which is the recyclerview within the vertical recyclerview:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android"
android:background="#color/white"
xmlns:app="http://schemas.android.com/apk/res-auto">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Favourite"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp"
android:layout_marginLeft="16dp"
android:id="#+id/header_fav"/>
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_below="#+id/header_fav"
android:id="#+id/recyclerview_fav">
</android.support.v7.widget.RecyclerView>
</RelativeLayout>
This has been bugging me for a while now and I have not managed to come up with a solution. Does anyone know how to solve this problem?
5 points to Griffindor for the correct answer and of course, reputation points on SO.

Tested solution:
All you need is to call mInnerRecycler.setNestedScrollingEnabled(false); on your inner RecyclerViews
Explanation:
RecyclerView has support for nested scrolling introduced in API 21 through implementing the NestedScrollingChild interface. This is a valuable feature when you have a scrolling view inside another one that scrolls in the same direction and you want to scroll the inner View only when focused.
In any case, RecyclerView by default calls RecyclerView.setNestedScrollingEnabled(true); on itself when initializing. Now, back to the problem, since both of your RecyclerViews are within the same ViewPager that has the AppBarBehavior, the CoordinateLayout has to decide which scroll to respond to when you scroll from your inner RecyclerView; when your inner RecyclerView's nested scrolling is enabled, it gets the scrolling focus and the CoordinateLayout will choose to respond to its scrolling over the outer RecyclerView's scrolling. The thing is that, since your inner RecyclerViews don't scroll vertically, there is no vertical scroll change (from the CoordinateLayout's point of view), and if there is no change, the AppBarLayout doesn't change either.
In your case, because your inner RecyclerViews are scrolling in a different direction, you can disable it, thus causing the CoordinateLayout to disregard its scrolling and respond to the outer RecyclerView's scrolling.
Notice:
The xml attribute android:nestedScrollingEnabled="boolean" is not intended for use with the RecyclerView, and an attempt to use android:nestedScrollingEnabled="false" will result in a java.lang.NullPointerException so, at least for now, you will have to do it in code.

if any one still looking , try this :
private val Y_BUFFER = 10
private var preX = 0f
private var preY = 0f
mView.rv.addOnItemTouchListener(object : RecyclerView.OnItemTouchListener {
override fun onTouchEvent(p0: RecyclerView, p1: MotionEvent) {
}
override fun onInterceptTouchEvent(rv: RecyclerView, e: MotionEvent): Boolean {
when (e.action) {
MotionEvent.ACTION_DOWN -> rv.parent.requestDisallowInterceptTouchEvent(true)
MotionEvent.ACTION_MOVE -> {
if (Math.abs(e.x - preX) > Math.abs(e.y - preY)) {
rv.parent.requestDisallowInterceptTouchEvent(true)
} else if (Math.abs(e.y - preY) > Y_BUFFER) {
rv.parent.requestDisallowInterceptTouchEvent(false)
}
}
}
preX = e.x
preY = e.y
return false
}
override fun onRequestDisallowInterceptTouchEvent(p0: Boolean) {
}
})
it checks if currently scrolling horizontal then don't allow parent to handel event

I am a bit late but this will defintly work for others facing the same problem
mRecyclerView.addOnItemTouchListener(new RecyclerView.OnItemTouchListener() {
#Override
public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
int action = e.getAction();
// Toast.makeText(getActivity(),"HERE",Toast.LENGTH_SHORT).show();
switch (action) {
case MotionEvent.ACTION_POINTER_UP:
rv.getParent().requestDisallowInterceptTouchEvent(true);
break;
}
return false;
}

Tested solution, use a custom NestedScrollView().
Code:
public class CustomNestedScrollView extends NestedScrollView {
public CustomNestedScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}
#Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
if (ev.getAction() == MotionEvent.ACTION_DOWN) {
// Explicitly call computeScroll() to make the Scroller compute itself
computeScroll();
}
return super.onInterceptTouchEvent(ev);
}
}

try
public OuterRecyclerViewAdapter(List<Item> items) {
//Constructor stuff
viewPool = new RecyclerView.RecycledViewPool();
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
//Create viewHolder etc
holder.innerRecyclerView.setRecycledViewPool(viewPool);
}
inner recylerview will use the same viewpool and it'll be smoother

I would suggest you add the horizontal recyclerview inside fragments like the google app

i read through the offered answers of using setNestedScrollingEnabled to false and it was awful for me as it makes the recyclerview not recycle and you can get crashes in memory, performance issues maybe etc if you have a huge list. so i will give you a algorithm to make it work without any code.
have a listener on the vertical recyclerview, such as a scroll listener. anytime the list is scrolled you will get a callback that its being scrolled. you should also get a call back when its idle.
now when vertical recylerview is being scrolled, setNestedScrollingEnabled = false on the horizontal list
once vertical recyclerview is idle setNestedScrollingEnabled = true on the same horizontal list.
also initially set the horizontal recyclerview to setNestedScrollingEnabled = false in xml
this can also work great also with appbarlayout when coordinatorLayout gets confused with two recyclerviews in different directions, but thats another question.
lets take a look at another more simple way in kotlin, to get this done with a real example. here we will focus just on the horizontal recyclerView:
assume we have RecyclerViewVertical & RecyclerViewHorizontal:
RecyclerViewHorizontal.apply {
addOnScrollListener(object : RecyclerView.OnScrollListener() {
override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
isNestedScrollingEnabled = RecyclerView.SCROLL_STATE_IDLE != newState
}
})
}
what this code says is if RecyclerViewHorizontal is not idle then enable nestedScrolling, otherwise disable it. That means when its idle we can now use the RecyclerViewVertical in a coordinatorlayout without any interference from the RecyclerViewHorizontal since we have disabled it when its idle.

Is it possible to touch the ImageView inside CollapsingToolbarLayout and scroll it?

I'm trying to get a fullscreen CollapsingToolbar but when I set match_parent to the height of AppBarLayout I'm not able to scroll the ImageView which is inside CollapsingToolbarLayout. I have to leave some space so that I can touch the "white" of the activity (in AppBarLayout I added android:layout-marginBottom:"16dp" ) and only then, after I touched it, I can scroll the ImageView otherwise I can't.
This happens everytime I run the app and touch the layout for the first time. So I have to touch the white first and then scroll the image.
Could you help me?
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:id="#+id/drawer">
<android.support.design.widget.CoordinatorLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="#+id/app_bar_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginBottom="16dp"
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="match_parent"
app:layout_scrollFlags="scroll|exitUntilCollapsed"
app:contentScrim="?attr/colorPrimary"
app:expandedTitleMarginStart="48dp"
app:expandedTitleMarginEnd="64dp">
<ImageView
android:id="#+id/image"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:scaleType="centerCrop"
android:fitsSystemWindows="true"
app:layout_collapseMode="parallax"
android:contentDescription="#null"
android:src="#drawable/background" />
<android.support.v7.widget.Toolbar
android:layout_height="?attr/actionBarSize"
android:layout_width="match_parent"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"
app:layout_collapseMode="pin"
app:theme="#style/ToolbarTheme"
android:id="#+id/toolbar"/>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v4.widget.NestedScrollView
android:id="#+id/scroll"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clipToPadding="false"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
</FrameLayout>
</android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>
<com.myapplication.ScrimInsetsFrameLayout
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="304dp"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="true"
app:insetForeground="#4000"
android:clickable="true"
android:background="#ffffff">
...
</com.myapplication.ScrimInsetsFrameLayout>
</android.support.v4.widget.DrawerLayout>
EDIT #PPartisan I've done what you said but here's what I got:

This isn't a nice solution, but it does work on my test device. It kick starts the scrolling process by explicitly assigning a touch listener to the AppBar that triggers a nested scroll.
First, create a custom class that extends NestedScrollView and add the following method so it look something like this:
public class CustomNestedScrollView extends NestedScrollView {
private int y;
public CustomNestedScrollView(Context context) {
super(context);
}
public CustomNestedScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public boolean dispatchHandlerScroll(MotionEvent e) {
switch (e.getAction()) {
case MotionEvent.ACTION_DOWN:
y = (int) e.getY();
startNestedScroll(2);
break;
case MotionEvent.ACTION_MOVE:
int dY = y - ((int)e.getY());
dispatchNestedPreScroll(0, dY, null, null);
dispatchNestedScroll(0, 0, 0, dY, null);
break;
case MotionEvent.ACTION_UP:
stopNestedScroll();
break;
}
return true;
}
}
Then, inside your Activity class, assign a TouchListener to your AppBarLayout:
appBarLayout.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
return customNestedScrollView.dispatchHandlerScroll(event);
}
});
and remove it when the AppBar collapses fully for the first time:
#Override
public boolean dispatchTouchEvent(MotionEvent ev) {
if (Math.abs(appBarLayout.getY()) == appBarLayout.getTotalScrollRange()) {
appBarLayout.setOnTouchListener(null);
}
return super.dispatchTouchEvent(ev);
}
Edit
Take the following steps to get it up and running:
Replace the NestedScrollView in your xml(android.support.v4.widget.NestedScrollView) with the CustomNestedScrollView (which will take the form of com.something.somethingelse.CustomNestedScrollView, depending on where it is in your project).
Assign it to a variable in your Activity onCreate()(i.e. CustomScrollView customScrollView = (CustomScrollView) findViewById(R.id.custom_scroll_view_id);)
Set up the TouchListener on your appBarLayout as you have done in your edit. Now when you call dispatchHandlerScroll(), it will be on your customNestedScrollView instance.
dispatchTouchEvent() is a method you override in your Activity class, so it should be outside the TouchListener
So, for example:
public class MainActivity extends AppCompatActivity {
private AppBarLayout appBarLayout;
private CustomNestedScrollView customNestedScrollView;
//...
#Override
protected void onCreate(Bundle savedInstanceState) {
//...
customNestedScrollView = (CustomNestedScrollView) findViewById(R.id.scroll);
appBarLayout = (AppBarLayout) findViewById(R.id.app_bar_layout);
appBarLayout.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
return customNestedScrollView.dispatchHandlerScroll(event);
}
});
}
#Override
public boolean dispatchTouchEvent(MotionEvent ev) {
if (Math.abs(appBarLayout.getY()) == appBarLayout.getTotalScrollRange()) {
appBarLayout.setOnTouchListener(null);
}
return super.dispatchTouchEvent(ev);
}
}
Hope that's cleared things up.

Try to add a tiny margin so the white space below will be almost invisible (you might also want to change white to accent color so the space will not be visible)
Another approach is to set the height of app bar layout dynamically by getting the height of the screen.
EDIT:
This might be a focus problem, try to add dummy layout to your main content, that will be focused automatically
<LinearLayout
android:layout_width="0px"
android:layout_height="0px"
android:focusable="true"
android:focusableInTouchMode="true" />
or even just add these attributes to your content layout
android:focusable="true"
android:focusableInTouchMode="true"

How do the animation hiding the ActionBar and keeping tabs?

In version 5 of Google Play Store app, scroll to the content, ActionBar on with scrolling, but the tabs are fixed to get on top.
How to do this?
BEFORE SCROLL
AFTER SCROLL

As others have suggested, use ObservableScrollView from: https://github.com/ksoichiro/Android-ObservableScrollView
Try putting both the Toolbar and the SlidingTabStrip in the same container, then animate that container as the user scrolls the ObservableScrollView, for example:
<FrameLayout 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"
tools:context=".MainActivity">
<com.github.ksoichiro.android.observablescrollview.ObservableListView
android:id="#+id/listView"
android:layout_height="match_parent"
android:layout_width="match_parent"/>
<LinearLayout
android:id="#+id/toolbarContainer"
android:orientation="vertical"
android:elevation="10dp"
android:background="#color/material_deep_teal_200"
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"/>
<!--Placeholder view, your tabstrip goes here-->
<View
android:layout_width="wrap_content"
android:layout_height="48dp"/>
</LinearLayout>
</FrameLayout>
Then when you override the ObservableScrollViewCallbacks you could do something like this:
#Override
public void onScrollChanged(int scrollY, boolean firstScroll, boolean dragging) {
toolbarContainer.animate().cancel();
int scrollDelta = scrollY - oldScrollY;
oldScrollY = scrollY;
float currentYTranslation = -toolbarContainer.getTranslationY();
float targetYTranslation = Math.min(Math.max(currentYTranslation + scrollDelta, 0), toolbarHeight);
toolbarContainer.setTranslationY(-targetYTranslation);
}
#Override
public void onUpOrCancelMotionEvent(ScrollState scrollState) {
float currentYTranslation = -toolbarContainer.getTranslationY();
int currentScroll = listView.getCurrentScrollY();
if (currentScroll < toolbarHeight) {
toolbarContainer.animate().translationY(0);
} else if (currentYTranslation > toolbarHeight /2) {
toolbarContainer.animate().translationY(-toolbarHeight);
} else {
toolbarContainer.animate().translationY(0);
}
}
The onUpOrCancelMotionEvent stuff is to animate the container to prevent the toolbar from being only half shown/hidden.
Here's a demo video just for reference: https://drive.google.com/file/d/0B7TH7VeIpgSQSzZER1NneWpYa1E/view?usp=sharing

Answer is here:
https://github.com/ksoichiro/Android-ObservableScrollView :D
This library is excellent for my case and very others

Great that you answer your question by yourself ;)
Here is another small hint:
Use a seperated layout for your tabs or integrate them into your toolbar and then tranlsate the toolbar only as far as you can see the tabs on top.

Android Viewpager as Header in ParallaxHeader Example does not scroll as expected

I am trying to implement the ParallaxHeaderViewPager like here. But instead using a KenBurnsSupportView and an ImageView as a Header i have used a FrameLayout that contains a ViewPager. My problem is that if i try to use vertical scroll on the Header the Event gets consumed but nothing happens. I can only scroll horizontally on the Header(ViewPager) and the Page changes correctly. But this is not what i want to accomplish. I want if i scroll vertically on the Header the event to be recognized as a ListView scroll and when i scroll horizontally (on the Header) as a ViewPager scroll. The scrolling is functioning correctly on the area that is not used from the header. Namely under the header where i have 4 Listviews I can scroll both vertically and horizontally. The Layout I am currently using is like the below code snippet:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<android.support.v4.view.ViewPager
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<FrameLayout
android:id="#+id/header"
android:layout_width="match_parent"
android:layout_height="#dimen/header_height" >
<FrameLayout
android:id="#+id/news_pager_content_area"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:background="#color/white"
/>
<com.astuetz.PagerSlidingTabStrip
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="48dip"
android:layout_gravity="bottom"
android:background="#android:color/transparent" />
</FrameLayout>
I have tried to subclass both the Listviews and the Viewpager to intercept and handle touch Events but it seems that the default behavior documented in the Android Documentation is not applicable in my example. Thank you for your help.

I solved my question trying all the answers at similar topics on Stackoverflow and looking at the Android Documentation again. I created a custom FrameLayout for the root container of the above Layout file. I override the dispatchTouchEvent method.
public boolean dispatchTouchEvent(MotionEvent ev)
{
switch (ev.Action)
{
case MotionEventActions.Down:
_xDistance = _yDistance = 0f;
_lastX = ev.GetX();
_lastY = ev.GetY();
_startY = _lastY;
_isFirstTime = true;
_downEvent = MotionEvent.obtain(ev);
break;
case MotionEventActions.Move:
float curX = ev.GetX();
float curY = ev.GetY();
_xDistance += Math.abs(curX - _lastX);
_yDistance += Math.abs(curY - _lastY);
_lastX = curX;
_lastY = curY;
float yDeltatTotal = curY - _startY;
if (_yDistance > _xDistance && Math.abs(yDeltatTotal) > _touchSlop)
{
if (_isFirstTime)
{
_isFirstTime = false;
return childView.dispatchTouchEvent(_downEvent);
}
return childView.dispatchTouchEvent(ev);
}
}
return super.DispatchTouchEvent(ev);
}
Where as ChildView I set the ViewPager with id = pager from the layout above. To avoid pointerindex out of range Exception I used the obtain method as specified by Dmitry Zaitsev in the first comment at this link.

MapFragment in ScrollView

I have one of the new MapFragments in a ScrollView. Actually it's a SupportMapFragment, but anyway. It works, but there are two problems:
When scrolled, it leaves a black mask behind. The black covers exactly the area where the map was, except for a hole where the +/- zoom buttons were. See screenshot below. This is on Android 4.0.
The view doesn't use requestDisallowInterceptTouchEvent() when the user interacts with the map to prevent the ScrollView intercepting touches, so if you try to pan vertically in the map, it just scrolls the containing ScrollView. I could theoretically derive a view class MapView and add that functionality, but how can I get MapFragment to use my customised MapView instead of the standard one?

Applying a transparent image over the mapview fragment seems to resolve the issue. It's not the prettiest, but it seems to work. Here's an XML snippet that shows this:
<RelativeLayout
android:id="#+id/relativeLayout1"
android:layout_width="match_parent"
android:layout_height="300dp" >
<fragment
android:id="#+id/map"
android:name="com.google.android.gms.maps.MapFragment"
android:layout_width="fill_parent"
android:layout_height="fill_parent"/>
<ImageView
android:id="#+id/imageView123"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:src="#drawable/temp_transparent" />
</RelativeLayout>

For me adding a transparent ImageView did not help remove the black mask completely. The top and bottom parts of map still showed the black mask while scrolling.
So the solution for it, I found in this answer with a small change.
I added,
android:layout_marginTop="-100dp"
android:layout_marginBottom="-100dp"
to my map fragment since it was vertical scrollview. So my layout now looked this way:
<RelativeLayout
android:id="#+id/map_layout"
android:layout_width="match_parent"
android:layout_height="300dp">
<fragment
android:id="#+id/mapview"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="-100dp"
android:layout_marginBottom="-100dp"
android:name="com.google.android.gms.maps.MapFragment"/>
<ImageView
android:id="#+id/transparent_image"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:src="#color/transparent" />
</RelativeLayout>
To solve the second part of the question I set requestDisallowInterceptTouchEvent(true) for my main ScrollView. When the user touched the transparent image and moved I disabled the touch on the transparent image for MotionEvent.ACTION_DOWN and MotionEvent.ACTION_MOVE so that map fragment can take Touch Events.
ScrollView mainScrollView = (ScrollView) findViewById(R.id.main_scrollview);
ImageView transparentImageView = (ImageView) findViewById(R.id.transparent_image);
transparentImageView.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
int action = event.getAction();
switch (action) {
case MotionEvent.ACTION_DOWN:
// Disallow ScrollView to intercept touch events.
mainScrollView.requestDisallowInterceptTouchEvent(true);
// Disable touch on transparent view
return false;
case MotionEvent.ACTION_UP:
// Allow ScrollView to intercept touch events.
mainScrollView.requestDisallowInterceptTouchEvent(false);
return true;
case MotionEvent.ACTION_MOVE:
mainScrollView.requestDisallowInterceptTouchEvent(true);
return false;
default:
return true;
}
}
});
This worked for me. Hope it helps you..

This probably has its roots in the same place at causes the problem in this question. The solution there is to use a transparent frame, which is a little lighter weight than a transparent image.

Done after lots of R&D:
fragment_one.xml should looks like:
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/scrollViewParent"
android:orientation="vertical" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="400dip" >
<com.google.android.gms.maps.MapView
android:id="#+id/mapView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<View
android:id="#+id/customView"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#android:color/transparent" />
</RelativeLayout>
<!-- Your other elements are here -->
</LinearLayout>
</ScrollView>
Your Java class of FragmentOne.java looks like:
private GoogleMap mMap;
private MapView mapView;
private UiSettings mUiSettings;
private View customView
onCreateView
mapView = (MapView) rootView.findViewById(R.id.mapView);
mapView.onCreate(savedInstanceState);
if (mapView != null) {
mMap = mapView.getMap();
mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
mUiSettings = mMap.getUiSettings();
mMap.setMyLocationEnabled(true);
mUiSettings.setCompassEnabled(true);
mUiSettings.setMyLocationButtonEnabled(false);
}
scrollViewParent = (ScrollView)rootView.findViewById(R.id.scrollViewParent);
customView = (View)rootView.findViewById(R.id.customView);
customView.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
int action = event.getAction();
switch (action) {
case MotionEvent.ACTION_DOWN:
// Disallow ScrollView to intercept touch events.
scrollViewParent.requestDisallowInterceptTouchEvent(true);
// Disable touch on transparent view
return false;
case MotionEvent.ACTION_UP:
// Allow ScrollView to intercept touch events.
scrollViewParent.requestDisallowInterceptTouchEvent(false);
return true;
case MotionEvent.ACTION_MOVE:
scrollViewParent.requestDisallowInterceptTouchEvent(true);
return false;
default:
return true;
}
}
});

I used this structures and I overcame the problem.
I used a container view for maps fragment.
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:text="Another elements in scroll view1"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<com.erolsoftware.views.MyMapFragmentContainer
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="250dp">
<fragment
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:id="#+id/eventMap"
tools:context="com.erolsoftware.eventapp.EventDetails"
android:name="com.google.android.gms.maps.SupportMapFragment"/>
</com.erolsoftware.views.MyMapFragmentContainer>
<TextView
android:text="Another elements in scroll view2"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
</ScrollView>
The container class:
public class MyMapFragmentContainer extends LinearLayout {
#Override
public boolean onInterceptTouchEvent(MotionEvent ev)
{
if (ev.getActionMasked() == MotionEvent.ACTION_DOWN)
{
ViewParent p = getParent();
if (p != null)
p.requestDisallowInterceptTouchEvent(true);
}
return false;
}
public MyMapFragmentContainer(Context context) {
super(context);
}
public MyMapFragmentContainer(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MyMapFragmentContainer(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
}

No need to struggle with customScrollViews and transparent layout files. simply use lighter version of google map and your issue will be resolved.
map:liteMode="true"
add above property inside map fragment in your layout file. and issue will be fixed.

For the second part of the question - you can derive a fragment class from SupportMapFragment, and use that in your layout instead. You can then override Fragment#onCreateView, and instantiate your custom MapView there.
If that does not work, you can always create your own fragment - then you just need to take care of calling all the lifecycle methods yourself (onCreate, onResume, etc). This answer has some more details.

<ScrollView
android:layout_width="match_parent"
::
::
::
<FrameLayout
android:id="#+id/map_add_business_one_rl"
android:layout_width="match_parent"
android:layout_height="100dp"
>
<fragment
android:id="#+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="-100dp"
android:layout_marginBottom="-100dp"
/>
</FrameLayout>
::
::
::
</ScrollView>