I have a readonly memo shwoing some text. However, there is a usability oddness. The user can pan the content in TMemo when only scroll ought to be possible.
Since people seem to think panning and scrolling is the same, I will give my definitions:
Panning = You can drag the entire content top/bottom/left/right (i.e. all
directions... NOT scrolling text but more like dragging entire "textview" object/widget. Also what is normally seen in image panning demos where you can pan the image in different directions to see e.g. top/bottom/left/right.)
Scrolling of text = scrolling of text the direction the content in the widget is placed (e.g. scrolling text up/down)
My question is how to only have scroll if possible. (And not be able to drag 2/3 of the entire text control out of the view although i bounces back when touch is let go)
What you are experiencing is an animation effect.
It can be turned off by setting the property:
AniCalculations.BoundsAnimation := false;
See FMX.InertialMovement.TAniCalculations.BoundsAnimation for more information.
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 trying to create the effect seen in some iOS apps where swiping the screen scrolls the ScollView/TextView normally, but sliding on the far right (where the scroll indicator is) creates a quick scrolling effect that allows the user to scroll through the position in the overall length of the view. For example, sliding on the far right from the middle of the screen to the bottom would take the TextView from the middle of its content to the very end.
Is there any pre-established way to do this, or is this an effect I would have to create from scratch?
Thanks a lot for any help, and I'm sorry if this question wasn't very clear.
I have a THorzScrollBox in a form, and some TStyledControls inside. Each StyledControl has a Tag to identify. Using an TEdit to inform a value, I can find inside the ScrollBox an specific Control by his tag.
If the control that I searched is not on the screen, I want to scroll the ScrollBox to show it.
How can I do this programmatically?
I found a way to do this.
I have to use ScrollBy. But the detail is that if I want to scroll the controls to right I have to use a negative value.
Example:
sbItems.ScrollBy(-10, 0); // this will scroll to right
If I use a positive value, it will scroll to left.
sbItems.ScrollBy(10, 0); // this will scroll to left
The point is, if you scroll once, the ViewportPosition will change and the next time you execute ScrollBy, it will not reset the scroll position, it will scroll from the point you already have scrolled.
I have implemented a UIScrollView for my game board, this board is a UIView consists of several images, the image of the board and some images of detail. And the zoom and scroll work well.
But what I do is that when I move the board will not let me get out of the board and see the bottom. Right now when I move the board around the edges sometimes see white, as my picture moves more than up to the stop.
What I want is to put a cap on scrollview not see what's behind only see the board.
I would also like to know if any of you know how I can do to drag images as a given within the board, as this all in a UIScrollView and I recognize there touch.
Thanks in advance
What I want is to put a cap on scrollview not see what's behind only see the board.
Yes, you can limit the visible area to just your content. Set the scroll view's bounces property to NO and make sure that the contentInset is 0. (0 is the default for contentInset, so it should be fine if you haven't changed it.)
how I can do to drag images as a given within the board
Scroll views have the option to delay touch events in the content view until the scroll view decides whether or not the user is trying to scroll. Read about the delaysContentTouches property. You'll probably want to leave that property set to YES. Beyond that, you really just need to learn to monitor touches -- you can drag a view by adjusting its position (by setting it's center, for example) as a touch moves around the screen. There's some sample code that may help you in Handling Swipe and Drag Gestures.
Backstory
I have an iPad app that needs to allow the user to navigate through groups of images. Each group is laid out in its own vertical UIScrollView (paged) so the user can swipe up and down down to see each image. Each of the group UIScrollViews is placed in a single (only one exists in the app) outer horizontal UIScrollView (also paged). This works great.... I can swipe up and down to view the images in a group and swipe left and right to go to the next or previous group.
Problem
The problem started when I needed to add zooming for each image. I accomplished this by placing each image inside its own UIScrollView. When the image is zoomed I can pan around the image and when I get to the top or the bottom of the zoomed image the group's vertical UIScrollView pages to the next or previous image as expected. Unfortunately the outer horizontal scrollview will not page to the next group when the image is zoomed and I pan to the leftmost or rightmost edge.
Is there a better(more correct) approach than triple nesting UIScrollViews or can I somehow forward touches to the outer horizontal scrollview?
Any help or suggestions would be greatly appreciated.
hope i'm not too late but I think I have a solution for your problem.
Here you can find an Xcode project demonstrating the scrollview setup you have, your problem and the proposed solution: https://bitbucket.org/reydan/threescrollviews
Basically the solution was to add 1 pixel to the contentSize.width of the vertical scrollviews. This forces the vertical scrollview to scroll a little when you pan to the edge of the zoomed image. It scrolls a little and then continues to the next vertical scrollview.
If you download the project you will see that I've created some scrollviews in the viewDidLoad method. There, I create one horizontal scrollview containing 3 vertical scrollviews, each containing 5 images. Each image is actually incapsulated in a scrollview to enable per-image zooming. In total... triple nested scrollviews.
I've also left some colored borders so that I can easily see how each scrollview scrolls.
the magenta = horizontal scrollview
the white = vertical scrollview
the blue = the image scrollview (the one that contains the image and allows for zooming)
the red = the UIImageView
You will see that I've tagged each image scrollview with value 10. This is used in the implementation of - (UIView*)viewForZoomingInScrollView:(UIScrollView *)scrollView delegate method where I return nil unless the event came from one of the image scrollviews.
If you have any questions about the project I made feel free to ask.
In the end, I would like to say that this browsing method is a little quirky for me as I sometimes scroll in the unwanted direction. Often I think I flick my finger vertically only to find the scrollview going left or right because it interpreted some tiny horizontal movement I had.
The problem I found with paging enabled for both horizontal and vertical movement is that the scrollviews are direction-locked, or so it seemed to me.
EDIT:
Today I've investigated the problem even more. These are my conclusions:
it's not a problem with zooming, it's a problem with having larger content in the innermost scrollview than the visible area(you can try this by zooming or simply initializing the content size larger than the bounds). This enables panning inside the inner-most scrollview and completely changes the behaviour of the touch events.
the bounce for a scrollview flag affects the behaviour of the panning(dragging) gesture when it reaches the edges of the content. If bounces=false then your panning gesture will stop at the edge, not forwarding the drag event up the chain (and thus not scrolling the parent scrollviews to show you other images). If bounces=true then, when you reach the edge and continue to drag the events will be forwarded to the parent scrollview and that scrollview will also be dragged. However, I've found that the dragging while bouncing reduces the distance dragged by aproximately 50%. This also happens in the Photos app.
if you start the dragging while the innermost scrollview is at the edge of the content then the scrollview is smart and will forward all events to the parent scrollview.
for some reason, triple nested scrollviews are problematic as the events are simply not forwarded between the topmost and middle scrollviews while panning inside the innermost scrollview. I have no idea why.
My solution with that +1 pixel to the content size, partially solves the problem.
EDIT 2013
Boy, these scrollviews are something out of this world :(
After more than a year of searching (just kidding... it was actually 2 days) I think I found a good elegant solution to the triple nested scrollviews.
I created a test project here:
https://github.com/reydanro/TripleNestedScrollViews
Inside the app, there is a switch which you can use to test with/without the fix.
The setup I am using in my app is a little different than this question. I have 1 vertical paged scrollview. Inside it, I have multiple horizontal paged scrollviews.
Inside some of the horizontal scrollviews I have another vertical paged scrollview.
Without the fix, once you get to the page with the inner-most scrollview you are pretty much stuck there as the vertical scrolling gestures are not forwarded to the outer-most scroll.
The fix is a custom UIGestureRecognizer that you need to add to the inner-most scrollviews. This recognizer follows touch events and if it detects a drag beyond the contentArea, then it will temporarily disable the rest of the scrollview's recognizers. This is the only method I discovered to make the scrollview forward the events up the chain
The gesture recognizer code is very rough with limited customization but should get the job done. At the moment I am focused on the app I develop, but will continue to update the repository.
PS: I haven't tested what happens with zoom but I see no reason why this method should not work (or be adapted to work).