I'm developing my first iPhone app and I would greatly appreciate you guy's input on a problem I'm having.
I'm looking to implement scrolling both horizontally and vertically. I want the horizontal scrolling to be paged, without the vertical one being paged (scrolling "normally"). A single UIScrollView with pagingEnabled set to YES will page in both directions. The natural solution would be to nest a UIScrollView inside another one, however when I do that, I can't get the "inner" UIScrollView to scroll at all. Seems the outer one is "eating" up all the tap events, like in:
UIScrollView : paging horizontally, scrolling vertically?
I read something about "inner scrolling" being improved upon in SDK 3.0 and actually when I add an inner UITableView instead of a UIScrollView the scrolling works flawlessly. Since UITableView subclasses UIScrollView I imagine that my desired behavior should be achievable by making my own subclass of UIScrollView.
Is this the right approach? If so, what should this subclass look like?
This works out of the box with the SDK now. See Scrolling Madness and Apple's UIPageControl sample for guidelines on how to implement paged horizontal scrolling with a view controller for each page.
The nested UIScrollViews you add as subviews to your outer UIScrollView should have the same frame heights as the container. If you do this then the outer UIScrollView will pass through the vertical scrolling events to the subview. My app has three levels of UIScrollView and UIWebView nesting and I've found Cocoa is really intelligent about passing the events to the one I want as long as I set my frame sizes so that only one view is really scrollable (contentSize > frame) on each axis.
If you are trying something like Twitter profile UI I achieved this by putting header view and bottom scrollview in a a parent scrollview and underlaying another scrollview behind.
Underlaying scrollview is responsible for the adjusting content offsets of header and bottom. Its contentsize is also adjusted by the inner item heights.
It looks complicated when I tell, better see the code
https://github.com/OfTheWolf/Twitterprofile
I've been using this great lib by Andrey Tarantsov for months: SoloComponents
You can use it as an "horizontal UITableView" with support for pagination and view recycling.
Well made and perfectly cocoa-style designed.
Based on Dylan's answer, in my case, I actually also had to make content size heights equal for both parent and nested UIScrollViews to make nested UIScrollView to scroll vertically. Making only "the same frame heights as the container" as Dylan explained was not enough:
parentScrollView.contentSize = CGSizeMake(parentScrollView.contentSize.width, desiredContentHeight);
nestedScrollView.contentSize = CGSizeMake(nestedScrollView.frame.size.width, desiredContentHeight);
What Dylan says. And, perhaps of interest on this topic - you do not need to enable scrolling in the master "paging" UIScrollView, just enable paging and direction lock. This seems to assure that all vertical scrolling cues go to the nested, fixed-size, vertical-scrolling NSScrollViews. It works back to at least iOS 9.
Related
I know that I asked a question a few minutes ago, but I want to make a few points clearer before asking for the community's help. I'm new to iOS development, close to finishing my first app. The only thing standing in my way is this UIScrollView. I simply do not understand it, and could use your help.
This is in the detail view controller of a drill-down app with a tab bar. I have approximately 8 fields (for things like phone numbers and such) drawing from a .plist. Obviously, those take up enough room that I could use a little extra real estate. I would guess that it needs to be about the size of two views vertically, but I do not understand how to allocate that sort of space to a UIScrollView. Some tutorials I have read say that you don't even need to define it in the header, which I doubt and do not understand. Additionally, I do not understand how to simply get the app to smoothly scroll up-and down only. Apple's examples have constant move cycles that flip between horizontal pictures.
I doubt it makes very much a difference, but I have an image that is in the background. I'm going to load the view on top of that.
My question is broad, so I don't expect you to take the time to sit down and write out all of the code for me (and I wouldn't ask you to). Just an outline of quick, helpful tips would help me understand how to get this view to load in the context of my project.
Many thanks!
It's fairly simple. Add a UIScrollView to your view. Add your fields and such to the scrollview. In viewDidLoad or somewhere similar, you need to set the contentSize on your scrollview. This is the "virtual" area that will be scrollable. This will generally be larger than the frame of the scrollview. In your case, you indicated it should be roughly double the width.
For instance, if you had a scrollview with a view inside, and you wanted to make sure the entire view is visible via scrolling:
self.scrollView.contentSize = self.contentView.frame.size;
//setting scrollview zoom level
self._scrollview.minimumZoomScale=0.5;
self._scrollview.maximumZoomScale=6.0;
self._scrollview.contentSize=CGSizeMake(320,500 );
you have to outlet scroll view in .h class and #property #synthesis this scroll view.then you can able to scroll up and down,if u want only vertical scrolling ,then u have to go to interface builder and uncheck the horizontal scrolling.
You can set a few settings for your scrollview to limit the scrolling to horizontal or vertical. A few important ones are:
// pseudcode here, start typing "[scrollView " then press escape to get a intelli-sense of all // the things you can set for the scrollview.
// values could be YES/NO or TRUE/FALSE, I can't remember which one but
// I think it's YES/NO. Once you start scrolling, the phone will determine
// which way you're scrolling then lock it to that direction
[scrollView setDirectionalLockEnabled:YES];
// when you slide the view, if enough of the next part of the view is visible,
// the scrollview will snap or bounce the scrollview to fit this new "page".
// think of swiping feature to navigate the iPhone home screens
// to show different "pages" of iphone apps
[scrollView setPagingEnabled:YES];
// as a safe guard, make sure the width of your scrollview fits snuggly with the content
// it is trying to display. If the width is more than necessary to display your table of
// data vertically, sometimes the scrollview will cause the
// horizontal scrolling that you don't want to happen and you get bi-directional scrolling
Just set the content size of UIScrollView after adding all the controls/button/textfields etc. for example you add 10 textfields in UIScrollview then content size of UIScrollView will be
lastTextField.frame.origin.y+lastTextField.frame.size.height+20; 20 is for margin.
That's it let me know if you want to know something more related to your app.
In my app, I have part of a view sticking out from the right. I would like the user to be able to swipe that to the left, to pull/reveal the rest of that view, which would basically almost cover the screen. See below:
I am figuring my best option is to use UIScrollView for two reasons. That I can lock the movement to horizontal only, and the animation for swiping is already built it.
My question is, can I have one page of the UIScrollView smaller than the other as shown in my mockup images?
UIScrollView horizontal paging like Mobile Safari tabs
I have a UIScrollView instance with many views inside. I have touchesBegan: defined inside my implementation of a subclass of UIView, but touches are only detected for views that are originally shown inside the scrollview (without scrolling). That is, initially all touches are detected, but when I scroll down, no touches are detected, except for on those views which were originally above the fold (i.e. they originally fit in the scrollview), and moreover, only those parts of those views which were above the fold (in the cases of views that were partially shown originally).
I hope this is clear... anyone have any idea what could be causing a situation like this?
After a day of debugging, I found the simple solution. The height of the frame of the view inside the scrollview had been set to the height of the screen. I needed to extend it to the full height of the scrollview.
I have got a hierarchy where UIScrollviews exist within each other.
How may I redirect swipe events for a certain area to an inner scrollview?
If you set your UIScrollViews to only be scrollable in one axis or the other (ie, set their contentSize property appropriately for this. To have a view only be scrollable vertically, set its contentSize.width value to be the same as its bounds.size.width). then they should just work, assuming that no two views scroll in the same axis. Usually, you'll have the 'child' views scroll vertically, and the parent view scroll horizontally.
If it's at all possible, you should redesign to avoid this. Safari handles this kind of situation, i.e. iframes and textareas, by having the embedded view scroll with two fingers. This isn't very discoverable, but it's better than the alternative, which would be even more frustrating. If an embedded view were just barely onscreen, an attempt to scroll the outer view could instead scroll the inner view, but not display much of anything; it would just appear to be non-responsive.
That said, If you still want to do this, try setting the outer scroll view's canCancelContentTouches to NO. This should prevent the outer view from scrolling when a touch begins in the inner view. Getting Safari-style two finger scrolling would probably involve subclassing UIScrollView and implementing the -touchesShouldBegin:withEvent:inContentView: method.
Client wants some tricky stuff and i don't really know where to start with it.
The idea is that there is a horizontal scrollView whose each page consists of a vertical scrollView.
For example, on the horizontal axis there are galleries, on the vertical we scroll through selected gallery's images. Is this even possible?
I'd be very glad to hear comments on this one!
You will have to manage the state yourself. When one scrollbar is selected the other has to be disabled and vice versa. You can also disable the user scrolling and handle the swiping yourself with the touch events. (on a clearColor UIView as a topmost view).
They all works magically, there's no additional work for this unless there's an issue about memory consumption which will require more coding.
Simply, create a horizontal scroll view then add vertical scroll views into it. Don't forget to update the contentSize property.