I have two problems with my UIScrollView, first, when i launch the app, the first screen i see is the one which contain the UIScrollView, so i try to scroll but i couldn't, it like if it is locked, so i navigate to other screens in the app, and when i go back to the first screen it scrolls very well.
the second problem is that when i scroll down and since i let the UIScrollView go, it bounces back to the top and so i can't interact with the content I just scrolled to.
check the #property contentSize. I bet it is set to CGSizeZero.
The height must be set to the maximum Y of the last element (in terms of Y-position) of your scrollView subviews.
You might want to have a look at this page, it has a lot of information regarding the UIS
Related
Sample Project
This is a sample project that showing the issue. It's storyboard based, but method of building interface doesn't matter. It's UIViewController with UIScrollView for entire screen and 128 pts height view that is on top of this UIScrollView.
Inside scroll view there is an UIView that has 2000 pts height and UIButton in the center.
Initial State
After light scroll
At the bottom of UIScrollView
Link here: https://github.com/JakubMazur/UITestsDemo
Problem
I'm trying to tap this green button with XCUITest using app.buttons["Tap Me!"].tap()
XCUITest get identifiers from elements on screen for entire scroll view that works fine.
According to this reply on a thread on Apple Developer Forum written by Apple Framework Engineer I shouldn't scroll manually to get to the button and yes, this is partially true.
What is happening when code from (1) is executed is that button is scrolled just enough to be visible on screen but it's still not hittable, because other (purple view) is on top of UIScrollView
What is working
If I run a test written like this:
func testThatDoWorkButItsSlow() {
app.scrollViews.firstMatch.swipeUp()
app.buttons[buttonLabel].tap()
}
that is scrolling up and then looks for a button this will work, but it's slow and so inaccurate that is hardly usable.
What I cannot do
Disabling userInteractions on purple view. In real example I still need touches for this (purple) view.
Questions
Is there a way to use precise scrolling in XCTest for this case?
Or is there a way to set contentOffset scrollview to other value that will make this button more centered on a screen compared to action of tap()?
Or there is a way to fast scroll to the bottom (without animations) and maybe moving only up for each element?
My recommendation here would be to use the XCUICoordinate.press(forDuration:thenDragTo:) method to scroll.
https://developer.apple.com/documentation/xctest/xcuicoordinate/1615003-press
You can create a XCUICoordinate for the yellow view, then drag it slightly upwards to expose the button and make it hittable.
In most cases, the automatic scroll should work, but it seems like in this case a manual scroll/drag is necessary.
The UI Testing should replicate human interactions. You cannot expect from a human being to scroll "153px", you can just expect to "scroll until".
You can try something like :
while (!app.buttons["Tap Me!"].isHittable) {
app.swipeUp()
}
NB: You may also want to add a condition to leave the while loop if you can't find the button after a reasonable amount of attempts
I'm using Xcode 6.4 and I'm struggling with a large page with a bunch of various labels and text fields etc., that has to be scrollable. I looked at various tutorials some of which are obviously outdated and I had all my elements at first in a view that is inside of a scroll view. But that was a big pain with getting all the elements aligned properly using Auto Layout, in addition to not getting it to scroll either.
Now I see one person recommend using the following directly on the elements, without having a content view at all just a scroll view:
Editor -> Embed In -> Scroll View
I like it for the fact that nothing seems out of proportion, all the elements are shown on the iPhone exactly as I have it on the Storyboard without having to set any constraints, however I'm not able to get it to scroll.
This is my class
class ResNotFoundViewController: UIViewController, UIScrollViewDelegate
and I also try to set the height of the scrollview in the code as so:
#IBOutlet weak var scrollviewoutlet: UIScrollView!
and then this in the viewDidLoad as so:
scrollviewoutlet.contentSize = CGSizeMake(375, 840)
.
But I'm not able to get it to scroll at all, it will stay exactly like it opens up with From: Label being the last visible elements.
What am I doing wrong?
You've located the problem, thanks to your logging. (Don't worry about the double call - how many times and when viewDidLayoutSubviews gets called is uninteresting.)
The problem is that you've set the scroll view itself to be taller than the window. In particular, it is 375x809. But so is its contentSize. Thus there is nothing to scroll. A scroll view can only scroll if its contentSize is bigger (in one or two dimensions) than the scroll view. (Moreover, a scroll view bigger than the screen is usually somewhat pointless, since there will be parts of its content that the user will never see - even scrolled all the way, that content will be offscreen.)
So, fix the size of the scroll view itself and you'll be fine. The best way is to assign it constraints that pin its boundaries to its superview, since the superview will have different sizes on different devices.
I'm having a little issue with scrollview pagination.
My intention is to have 3 pages visible on screen and when I scroll right only on page is scrolled, following the example below, scrolling right will display page 2, 3 and 4 on screen:
However I don't know how to display mutiple pages at the same time, at the moment I have it like this:
Obviously like this is not what I want.
To achieve the desired functionality I tried making the scrollview's frame the size of the page I want (1/3 of the screen width) and setting the clipToBound to NO so the other pages are visible. This indeed shows 3 pages in the screen; however since the scrollview frame is only 1/3 of the screen I can only swipe in that area, I would like the swipe area to be the whole screen width.
You're on the right path. Now you can try manipulating UIPanGestureRecognizer of your scrollView, say, re-attaching it to scrollView's superview.
Alternatively, take a look at iCarousel, it can be perfectly customized to suit your needs.
My solution in the end was the following:
I took my initial approach.
I disabled the scrollview's scrollEnabled property.
Added swipe gesture recognisers to the scrollview.
When the gesture is made I modify the scrollview's contentOffset to move 320/3 pixels to the right or left.
I'm trying to create custom vertical UIScrollView which could handle multiple pages with different page heights.
Assumptions:
page height is equal or greater than screen height
if page is taller than screen height, it scrolls as usual UIScrollView – with bouncing on top and bottom
if user ends up scrolling and "page break" is in the middle of screen
if there is no velocity - page snaps to closest
if there is velocity - page changes to one in direction of swipe
I've tried many approaches to achieve this, but I've stumbled upon many UIScrollView quirks, which make it hard.
Problems:
UIPanGestureRecognizer has unreliable method for getting velocity (velocityInView:)
scrollViewWillEndDragging:withVelocity:targetContentOffset: method gives me headache, because it arbitrarily can destroy my attempts to animate setting content offset
I don't know how to achieve bounce in one of the middle pages, I'm afraid i would have to rewrite whole scrolling handling
when I try to override setting content offset when UIScrollView is decelerating, what I get is
my content offset is set
deceleration continues beyond content offset I set
Bonus
I have also tried putting UIScrollView inside UIScrollView as a page, but this approach was also pain in the neck. For example when I was at the bottom of inside scroll, then i scrolled down a bit, put my finger away and quickly grabbed again and scrolled upwards, the outer scroll received touch, which messed up inside scroll presentation.
Does somebody have any idea how to do this? Any tips will be helpful as I'm completely stuck...
Try this. Might help. Based on the Circa news app.
https://www.cocoacontrols.com/controls/rscircapagecontrol
I've got a scrollview that allows the user to scroll between different pages and then tap on one to have it expand so that they can read the page in full, a little like how one changes tabs in Safari on the iPhone. Changing the frame size of each sub view is a bit of a pain when rotating as the scroll position is getting lost as the content size of the sub view has to change too. I was wondering if there was a more effective way of
resizing the views for entering 'viewing' mode or rotating the device.
The solution to your first problem is when you want to expand the view, pull it out of the scrollView then add it to self.view.subviews with an appropriate frame, then animate the frame to fill the screen. When done with it do the reverse, shrink it, then when its back to the appropriate size stick it back in the scrollView.
If for some reason this does not work - the scrollview is showing other stuff that gets moved when you remove the view, then instead of just removing your view from it, create a simple UIView of the same size as the view you will expand, and essentially replace the view you pull out with the "placeholder" view.