Develop Reference

OnTouchListener for ViewPager2

I recently changed the ViewPager in my application to a ViewPager2. I had set an onTouchListener to the viewPager object to detect gestures (onFling and onLongPress), as such:
mViewPager.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View view, MotionEvent motionEvent) {
mDetector.onTouchEvent(motionEvent); // use the custom gesture detector to detect onFling and onLongPress touch events.
return true;
}
});
The onTouchListener for the viewPager was working fine before the refactor to the ViewPager2. I tried this answer, but it didn't work.
Anyone has an idea as to why this might be the case and how I could fix it?

Because ViewPager2 is a ViewGroup, the final target is the recyclerview in it. The setOnTouchListener is not called because the recyclerview intercepts the event and calls the onTouchEvent first.
The right way to add customised onTouch logic is to call
mViewPager.getChildAt(0).setOnTouchListener{...}

The right way to add customised onTouch logic is to call
viewPager2.getChildAt(viewPager2.getCurrentItem()).setOnTouchListener(...)

dispatchTouchEvent and onTouchEvent in Android

Helle there,
I've been working with the CoordinateLayout inside i have nestedScrollview layout and it's childs.
It's similar to whats'app profile view. I have tried to mimic this ontouch and dispatchtouch event for more than two days without success.
I read lot about dispatchTouch event onTouchEvent, setOntouchListener. and it's related video's.
I read about Managing ViewGroup reference in android reference, but still it's confuses me. How to handle those touch events.In nestedScrollView i have child linearlayout and this layout contains lot of child views like button and edittext.
When i touch nestedScrollview (ActionDown) triggered and subsequently (ActionUp) started to scroll, but when i touch any of it's child's view it should wait for the movement of my finger and then start to call nestedScrollview if its a (ActionMove).
I've dealing this inside of AppCompatActivity.
How do i achieve this? Please help.
Thanks.

Stupid enough to play with what i don't understand.
I was able to mimic like whatsapp profile,
#Override
public boolean dispatchTouchEvent(MotionEvent motionEvent) {
nestedScrollview.onTouchEvent(motionEvent);
return super.dispatchTouchEvent(motionEvent);
}
call actionMove on child view to consume the event. Voila this did that trick. How ever the Scroll was not smooth compared to the mimic :0
Call this child.setOnTouchListener
case MotionEvent.ACTION_MOVE:
if (zeroY < mTouchSlop) {
mIsScrolling = true;
Log.d(DEBUG_TAG, "general" + Float.toString(zeroY) + " " + Float.toString(plusY));
}
return true;

How to make ViewPager scrollable from the parent view?

I was implementing the app tutorial which looks like this.
I made a nice and small ViewPager and placed it on the mock-up ImageView. The problem is that the ViewPager is not scrolled when I try to scroll it from elsewhere, say around the view pager indicators. This is so natural because there's no way that the ViewPager listens to touch event outside of itself.
How can I make ViewPager be scrolled when I try to scroll from elsewhere?
I've tried to detect touch events on the parent of the ViewPager but I couldn't figure out how to relate onFling() or onScroll() to ViewPager's scrolling.
If there's any better suggestion of implementing this kind of UI, what would be it?
Is there any tutorial or custom library similar to this?

set a View.OnTouchListener for your outer ViewPager and check inside if you are on proper page which is displaying inner ViewPager. if inner ViewPager isn't on its first or last you might dispatch MotionEvent to second dispatchTouchEvent(MotionEvent me)
outerViewPager.setOnTouchListener(new OnTouchListener()
{
#Override
public boolean onTouch(View v, MotionEvent event)
{
if(outerViewPagerAdapter.isCurrentPageHaveInnerViewPager() &&
! innerViewPagerAdapter.isOnFirstOrLastPage()){
innerViewPagerAdapter.dispatchTouchEvent(event);
return true;
}
return super.onTouch(event); //outer will get touch events
}
});
you might also adjust x/y touch cords in event before dispatching if needed

Android make two overlapping views receive and handle the same touch event

I'm using a RelativeLayout to overlap two different views. Both Views fill the entire Screen.
If the user touches the screen, I want both views to receive the TouchEvent and to excecute their own onTouch-Methods. At the moment, only one view receives the TouchEvent
How can I make both views receive the TouchEvent?
Thank you in advance for your help.
EDIT: Here's the code
touchView.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
view1.onTouchEvent(event);
view2.onTouchEvent(event);
return false;
}
});

You can create a third invisible View and place it on top of the overlapping part. Then in its TouchEvent perform the actions of those two TouchEvents

For top view assign clickable=false
it will allow the touch to intercept through it

You could try to get to check if the rawX & rawY of the TouchEvent are within the hitRect of the view that didn't get the event. If it did, you can use dispatchTouchEvent(MotionEvent) to send the TouchEvent tot the view that didn't get the event

Create a linearview on every activity to perfom action

I am trying to create view that sites underneath all others that will perform an action when 3 fingers are touched. These activities all have their own touches and swipes.
I have got this to kind of work by creating a class that extends linearlayout and intercepting touches. and adding this in xml.
But this is only being called when an item like button or view is a clickable or touchable surface and isn't becoming a touchable surface itself.
in
public class MyCatcher extends LinearLayout {
#Override
public boolean onInterceptTouchEvent(MotionEvent event) {
int action = event.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_POINTER_DOWN:
// multitouch!! - touch down
int count = event.getPointerCount(); // Number of 'fingers' in this
if (count > 3) {
doThis(mContext);
}
}
return super.onInterceptTouchEvent(event);
}
And in xml
<packagename.MyCatcher
....>
my normal layout
</packagename.MyCatcher>
So this code is working when an item that is touchable is touched but not becoming its own touch layer.
I have tried setontouchlister in the constructor with no luck.
Thanks for any help
EXTRA: When setting the touchlistener via onAttach I can get it to catch touches but I can't use event.getPointerCount() like normal as it's returning 1.
I'm worried this may take up lots of processing?/

Instead of a Layout, create a normal View and add it to your existing layout so that it spans the whole screen and lays "above" all other views (in z-order). Now it should get all touch events prior to all other views. Your onTouch... implementation should make sure to pass all touch events along to the other views (except if you want e.g. buttons not to work under certain circumstances, then do not pass the events along).

onintercepttouchevent()
Is called only whenever a touch event is occured. ie; touch event occurs only when a view item like button,textbox,etc having onclicklistener enabled is pressed . For your question you need to set the onclicklistener for the entire view.