I have a scrollView. Typical tableView Cell. I did things a lot on viewDidScroll.
viewDidScroll is called on 2 cases.
User scroll
Sometimes user have stop scrolling but the scrollview still scroll anyway due to momentum, bouncing, etc.
So how do I know if users are still touching the scrollView?
UIScrollView has a BOOL property named tracking that is YES while the scroll view has a touch and NO otherwise. In my testing, it is set to NO as soon as the touch ends, even if the view is decelerating (and still sending scrollViewDidScroll: to its delegate). This seems like exactly what you are asking for.
In my testing, the dragging property doesn't seem to become NO reliably while the view is decelerating after the touch ends.
The decelerating property is also unreliable in my testing. If I touch the scroll view while it is decelerating, decelerating remains YES even though the view has stopped scrolling.
The delegate's scrollViewWillBeginDragging: is called when user starts dragging and scrollViewDidEndDragging:willDecelerate: & scrollViewWillEndDragging:withVelocity:targetContentOffset:(iOS 5+ without paging enabled) is called when user lefts his/her fingers.
You may also want to check scrollViewWillBeginDecelerating: and scrollViewDidEndDecelerating:.
Ref: http://developer.apple.com/library/ios/#documentation/uikit/reference/uiscrollviewdelegate_protocol/Reference/UIScrollViewDelegate.html
Related
I've been struggling with first responder problem. I put web controller (UIWebView) inside UITableViewCell and now I would like to scroll vertically my table and not affect UIWebView (this case may be done by disabling scrolling scrollview from UIWebView). However problem appears when user zooms into web content, then I want scroll horizontally through web content and still vertically scroll in table (cause cell will be resized to zoomed content).
There is a property called 'multipleTouchEnabled' that should disable the pinch gesture, but I think the user would still be able to double-tap (assuming the cell doesn't consume this gesture). Why not, instead of creating multiple UIWebView's (which have a large overhead) don't you create one hidden UIWebView that loads a website and caches an image, then load this image into the cell.
Ultimately, if you still wanted to use the UIWebView approach, you could probably subclass it and override hitTest/touches methods or handle the gesture recognizers yourself.
Also, if this is for iOS8 I would be using the WKWebView instead.
I was able to get this working in iOS but I am having trouble with Win 8. What I need to do is this:
I have a drawing view that is the forward most child of a ScrollViewer. When I enable drawing mode from a button in the app bar, this view becomes active. With one touch, I want the user to be able to perform the current drawing action, but with two touches I want the touches to go to the scroll view instead for scrolling and zooming. I am able to distinguish between 1 and 2 (or more) fingers, but I don't know what to do after that point.
I tried removing the manipulation mode from the drawing view so that it would not block the scroll view, but the touches continued to be swallowed by the drawing view. I also tried calling ReleasePointerCapture but that had no effect either. How can I forward touch events using the WinRT API?
For some more information, I am making use of the PointerPressed, PointerChanged, etc events in the drawing view.
I have a subview with a UIButton added to a UIScrollView.
The button is working perfectly as long as the user isn't scrolling.
If the UIScrollView is still scrolling when the user clicks on the button, it just stops the scrolling instead(like if a row had been clicked).
Anyone know how to fix this?
First, make sure this really is the behavior you want - iOS users are used to scrolling views and touching to stop them with a tap without triggering button presses. Non-standard behavior (even when you think its better then the standard behavior) can be confusing to users used to how things work in other iOS apps - it can violate their mental model. Ok, note of caution over.
So how do you fix this? UIScrollView delays sending touch events until it knows if those touches are scroll events. You problem is a user tapping is a scroll event when the UIScrollView is moving. Two possible solutions:
Stop the UIScrollView from delaying any touch events it gets. You can set any scroll views delaysContentTouches to NO, which will stop the delaying action and should allow your buttons to be tapped while scrolling. You can read about it in the UIScrollView class documentation. You will also want to read up on canCancelContentTouches there as well.
Subclass the UIScrollView to add your own logic about where touch events should go. Here is a blog post that discusses how to do this.
I subclassed NSTextView and added support for automatic scrolling in a userdefineable time.
Now I want to detect, if the user manually scrolls, while the view is scrolling automatically.
Then I want to immediately stop automatic scrolling, until the user stops his action and then I want to start scrolling again from the new position.
I want to do this in such a matter, that the user can move around without a stuttering view.
I use boundsDidChangeNotification to calculate the scrolling position (playtime) and show it in a label, but I can't use it to detect the user manual scrolling, because it is also pushed by the automatic scrolling...
Would be very nice, if anyone has an idea ;-)
Thanks in advance
Gerald
I’ve got a view that has to be presented both in landscape and portrait. The transition between different orientations is done by repositioning and resizing the subviews. One of the subviews is a button (plain UIButton with an image background). When the interface rotates to landscape, the button starts misbehaving – it can only be tapped on its left part, the right part does not respond. When I move the button a bit to the left, the tappable part grows. The button should not be obscured by any other view, it’s clearly visible. When I override the hitTest:withEvent: method in the parent view, I see that the taps in the “numb” part of the button result in nil being returned. I think I have seen this behaviour once before, but unfortunately I’ve forgotten the source of the problem :) Any help?
Ah yes, I forgot to resize the view itself. Thus the button was on the boundary of the view and even though it was not clipped, the part lying outside the view frame was not considered for hit tests.