I'm using a ViewPager for swiping through pages, and each of these pages contains a NestedScrollView and a RecyclerView. The NestedScrollView is used to scroll the chart when using in split-screen mode.
fragment_accounts:
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<ProgressBar
android:id="@+id/mAccountsProgressbar"
style="?android:attr/progressBarStyleHorizontal"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:visibility="gone"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:visibility="visible" />
<androidx.core.widget.NestedScrollView
android:id="@+id/mAccountsScrollView"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/mAccountsProgressbar">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<at.guger.moneybook.core.ui.widget.StrokePieChart
android:id="@+id/mAccountsPieChart"
android:layout_width="match_parent"
android:layout_height="@dimen/default_chart_height"
app:accounts="@{viewModel.accounts}"
app:bold="true"
app:fontResId="@font/eczar_regular"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/mAccountsProgressbar"
app:textSize="42sp"
tools:text="$ 1234,56" />
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/mAccountsRecyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="8dp"
tools:itemCount="4"
tools:listitem="@layout/item_account" />
</LinearLayout>
</androidx.core.widget.NestedScrollView>
</androidx.constraintlayout.widget.ConstraintLayout>
Now, I'm using an OnTouchListener, to detect clicks in my RecyclerView. When swiping between pages in the ViewPager, the RecyclerView also detects long presses onto an item in the RecyclerView. How can I make sure, the RecyclerView does not use touch events when swiping to the next page?
To clearify: I want to receive long press events on items in the RecyclerView, but I don't want to receive them when the user is swiping between pages of the ViewPager!
OnItemTouchListener:
class OnItemTouchListener(context: Context, recyclerView: RecyclerView, private val onTouchCallback: ItemTouchListener) : RecyclerView.OnItemTouchListener {
//region Variables
private val gestureDetector: GestureDetectorCompat
//endregion
init {
gestureDetector = GestureDetectorCompat(context, object : GestureDetector.SimpleOnGestureListener() {
private val MIN_SWIPE_DISTANCE: Int = 50
private lateinit var downMotionEvent: MotionEvent
override fun onDown(e: MotionEvent?): Boolean {
e?.let { downMotionEvent = it }
return super.onDown(e)
}
override fun onSingleTapUp(e: MotionEvent?): Boolean {
return true
}
override fun onLongPress(e: MotionEvent?) {
e?.let {
val child: View? = recyclerView.findChildViewUnder(it.x, it.y)
if (child != null && !isGestureSwipe(it)) {
onTouchCallback.onItemLongClick(child, recyclerView.getChildLayoutPosition(child), it)
}
}
super.onLongPress(e)
}
fun isGestureSwipe(e: MotionEvent): Boolean {
return downMotionEvent.x - e.x >= MIN_SWIPE_DISTANCE
}
})
}
//region TouchHandler
override fun onInterceptTouchEvent(rv: RecyclerView, e: MotionEvent): Boolean {
val childView = rv.findChildViewUnder(e.x, e.y)
if (childView != null && gestureDetector.onTouchEvent(e)) {
onTouchCallback.onItemClick(childView, rv.getChildLayoutPosition(childView), e)
}
return false
}
override fun onRequestDisallowInterceptTouchEvent(disallowIntercept: Boolean) {
}
override fun onTouchEvent(rv: RecyclerView, e: MotionEvent) {
}
//endregion
interface ItemTouchListener {
fun onItemClick(view: View, pos: Int, e: MotionEvent)
fun onItemLongClick(view: View, pos: Int, e: MotionEvent)
}
companion object {
fun isViewClicked(container: View, @IdRes viewId: Int, e: MotionEvent): Boolean {
val view = container.findViewById<View>(viewId)
return isViewClicked(view, e)
}
fun isViewClicked(view: View, e: MotionEvent): Boolean {
val rect = Rect()
view.getGlobalVisibleRect(rect)
return view.isVisible && rect.contains(e.rawX.toInt(), e.rawY.toInt())
}
}
}
Parent Fragment, where fragment_accounts is embedded:
<androidx.coordinatorlayout.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">
<androidx.constraintlayout.widget.ConstraintLayout
android:id="@+id/mHomeConstraintLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent">
<androidx.viewpager2.widget.ViewPager2
android:id="@+id/mHomeViewPager"
android:layout_width="0dp"
android:layout_height="0dp"
android:orientation="horizontal"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/mHomeTabs" />
<at.guger.moneybook.core.ui.widget.LabelVisibilityTabLayout
android:id="@+id/mHomeTabs"
style="@style/Widget.MaterialComponents.TabLayout"
android:layout_width="0dp"
android:layout_height="?attr/actionBarSize"
android:backgroundTint="@android:color/transparent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:tabIconTint="@color/tab_highlight_selector"
app:tabIndicator="@null"
app:tabInlineLabel="true"
app:tabMode="scrollable"
app:tabRippleColor="@color/colorRippleMaterialDark"
app:tabTextColor="@color/tab_highlight_selector" />
</androidx.constraintlayout.widget.ConstraintLayout>
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="@+id/fabHomeAddTransaction"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="16dp"
android:layout_marginBottom="16dp"
android:backgroundTint="?colorPrimary"
android:clickable="true"
android:contentDescription="@string/AddTransaction"
android:focusable="true"
android:src="@drawable/ic_add"
app:layout_anchor="@+id/mHomeConstraintLayout"
app:layout_anchorGravity="bottom|end"
app:tint="?colorOnPrimary" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>
All the other code can be found on Github (https://github.com/guger/MoneyBook).
question from:
https://stackoverflow.com/questions/65935433/touch-event-interception-when-using-viewpager-nestedscrollview-recyclerview 
