How to create up/down swipeable UITableView? - ios

Question

I have a UITableView in the bottom of UIViewController and tableview height is 100 point now.
The tableview has 20 cells and tableview's header view is 100 point. And I've added a up UISwipeGestureRecognizer and a down UISwipeGestureRecognizer in table view header.
Now I want to change the tableview height constraint constant to 400 in up gesture action and change the tableview height constraint constant to 100 in down gesture action.
Now the problem is gesture recognizer isnt working in tableview
header when tableview scroll is enabled.
If tableview scroll is disabled then the gesture recognizer is
working. But unable to view all cells once the tableview height is
changed.

Answer 1

Here's a different approach. Don't use swipe gesture recognizers at all.
Instead, make the table always the full 400 points tall. Set its contentInset.top to 300. This will allow the table view to scroll so that only its top 100 points of content are visible at the bottom of the screen. Specifically, the table view will allow its contentOffset.y (which is its vertical scrolling position) to go down to -300 (instead of only down to 0). The table's content always starts at y = 0, so when the table's contentOffset.y is -300, only the top 100 points of its content are visible. As the contentOffset.y increases, more of its content becomes visible.
Then, override the table view's point(inside:withEvent:) method to return true only for points with y >= 0. This means the table will ignore (pass through) touches above its content when its content is scrolled so only the top 100 points are visible.
This is the final effect for a small table:
or for a big table:
You can find a detailed explanation (in Objective-C) and a link to the full test project (also in Objective-C) in this answer.

Answer 2

As it may help others, here is the simplest possible solution to this type of problem.
Extremely simple solution -
no tricks, nothing fancy -
don't have a "table view header".
Just make a new UIViewController
class TableWithRedTop: UIViewController
that has ...
[ red area .. swipe detection ]
[ main area - the table view]
Then simply put 'TableWithRedTop' inside a container view.
(Container view tutorial if you need one.)
In your MainView just have a call
func toggleTableHeight
When 'TableWithRedTop' gets a swipe, have one line of code to call toggleTableHeight in MainView
Note that in toggleTableHeight you can easily animate the height change, tilt it on an angle, duplicate it or do anything you want, as you're using a container view in MainView.

Answer 3

I'm going to make another suggestion that may solve the issue for you.
It could be what you want is an:
"self-expanding" table...
First implement the following with no animations, for simplicity.
You have two heights for the table, small and large.
Start the table on height small.
Remarkably, you only have to implement these two rules: just two simple lines of code:
Any time the user is scrolling upwards - in fact, change to "height large".
Any time the user is scrolling downwards, and, you are at the top position of the table (i.e. you can see cell #1) in fact change to "height small".
It's one of those things that is "so simple, it's hard to believe it works!"
It's sometimes referred to as a "pull-up table" I think.
(Note. If you're not familiar with detecting when the user is scrolling, fortunately it is trivial - code shown here for example.)

Answer 4

Set both swipe gesture’s cancelsTouchesInView to true and make sure that the gestures are added directly to the header and not the tableView.
That should do the trick, but so should adding a view with the gesture recognizes to the container view and setting it’s constraints to match the tableView’s top, left, and right constraints and setting its height to 100.