I do extend NestedScrollView and @Override it's methods: onTouchEvent and onInterceptTouchEvent. The problem is that super.onTouchEvent never calls ACTION_DOWN (it's called by my onIntereceptTouchEvent) and because of that NestedScrollView doesn't move and I get error:
Invalid pointerId=-1 in onTouchEvent
The pointer id is set in onTouchEvent method of NestedScrollView when ACTION_DOWN is triggered.
mActivePointerId = MotionEventCompat.getPointerId(ev, 0);
I cannot set this myself, rewriting whole onTouchEvent methods seems like painful plan. Could use help here. NestedScrollView does move when I click on View which doesn't listen for touch events (basicly that way my onInterecptTouchEvent method is not called and ACTION_DOWN is handled in NestedScrollView onTouchEvent).
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
Log.i(LOGTAG, String.valueOf(ev.getAction()));
final int action = MotionEventCompat.getActionMasked(ev);
if (action == MotionEvent.ACTION_CANCEL || action == MotionEvent.ACTION_UP) {
mIsBeingDragged = false;
Log.i(LOGTAG, "is scrolling" + String.valueOf(mIsBeingDragged));
return false; // Do not intercept touch event, let the child handle it
}
switch (action) {
case MotionEvent.ACTION_DOWN: {
mStartY = ev.getY();
break;
}
case MotionEvent.ACTION_MOVE: {
if (mIsBeingDragged) {
return true;
}
final int yDiff = calculateDistanceY(ev);
Log.d(LOGTAG, "y difference: y");
if (yDiff > mTouchSlop) {
mIsBeingDragged = true;
return true;
}
break;
}
}
return false;
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
Log.i(LOGTAG, "onTouchEvent");
if (ev.getAction() == MotionEvent.ACTION_CANCEL || ev.getAction() == MotionEvent.ACTION_UP) {
mIsBeingDragged = false;
}
return super.onTouchEvent(ev);
}
Below is the code that fixed my issue, I had to lie:
@Override
public boolean onTouchEvent(MotionEvent ev) {
Log.i(LOGTAG, "onTouchEvent");
if (ev.getAction() == MotionEvent.ACTION_CANCEL || ev.getAction() == MotionEvent.ACTION_UP) {
mIsBeingDragged = true;
}
if (mFirstOnTouchEvent) {
ev.setAction(MotionEvent.ACTION_DOWN);
ev.setLocation(mStartX, mStartY);
mFirstOnTouchEvent = false;
}
return super.onTouchEvent(ev);
}
And set mFirstOnTouchEvent to true when ACTION_DOWN is triggered in onInterceptTouchEvent:
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
if (MotionEventCompat.getActionMasked(ev) == MotionEvent.ACTION_DOWN) {
mFirstOnTouchEvent = true
}
...
}