I know there is stuff on GithHub which lets you implement a sleek 'pull down to sync' if you are in an UITableView.
However, all I would need to do is to know if the UITableView has been pulled down. I know there is a - (void)scrollViewDidScroll:(UIScrollView *)scrollView function, but that does not appear to fire if I scroll in an UITableView.
All I would need to know is, I suppose, if the UITableView scrolled beyond the upper bonds (which would give a minus figure, I suppose).
I'd be very grateful if anyone has any suggestions / solutions to this problem. Thanks in advance!
You don't say if your UITableView is being managed by a UITableViewController or you are managing it yourself. UITableView will send scrollViewDidScroll: messages, but only to the delegate of the table view instance.
Since you're saying scrollViewDidScroll: is not firing, I assume you are not subclassing UITableViewController and doing something else. Add the method to your table view's delegate and you will be notified of the scroll position changes.
I'd recommend EGORefreshTableHeaderView. Available on GitHub and works great.
Related
I'm trying to make a custom table view. I have a UIScrollView loaded up with UIViews. I would like to recreate the reusable cell functionality that a tableview has. And I'm wondering what might be a good way to do this.
I was thinking that when the UIViews are scrolled off screen I'll remove them from the Subview, and when I need another I'll just add it. However I'm not sure what method might be the best to do this in.
I could check to see the views location in scrollViewDidScroll: but I'm not sure if this would be the best thing to check over and over again. If anyone has any suggestions or helpful tips that would be really awesome.
Thanks!
One reason why scrollViewDidScroll is less than ideal choice is that your scroll view subclass will then need to be its own delegate. That will deny the users of that class the chance to be the delegate (easily, at least).
The better place to check this is in overriding layoutSubviews. And yes, like scrollViewDidScroll, it gets called a lot! But if you think about it, the only way to detect with certainty if any subview has been scrolled off, is to check when any scrolling occurs.
So the key is to be as efficient as you can checking. The first thing I'd try is fast enumeration of the subviews, asking if each frame transformed by contentOffset falls within the parent's bounds (using CGRectIntersectsRect). If not, add it to your reuse pool and remove it from superview.
Subclass UIScrollView and override setContentOffset. That's where the scrollViewDidScroll message comes from in the original UITableView, and that's where you can implement your own logic.
Edit: you might want to study the source code for PSTCollectionView, which is not a custom UITableView but a custom UICollectionView.
I am implementing a UIScrollView which behaves mostly like a UITableView, a bit more advanced with that.. but most of the API used are the same signature.. cellForRowAtIndexPath.. etc. First before people start storming why not just use a UITableView, let me just say that I can't. The reasons are fairly complex, but that is a decision been made.
The issue is now I am implementing infinite scrolling, basically when I scroll down and I am at 65% of the full contentHeight I am doing an async request to the backend to fetch more data and adding it to the data source and then calling reloadData. The issue is that if I am calling reloadData while the user is scrolling, it doesn't provide a very smooth scrolling experience. So what is the best way to tackle this? Also I noticed that reloadData basically refreshes the entire table view (in this case my scroll view). In my table view cell I am animating a UIImage to fade in. So when reloadData is called, the image that is already presented is being faded in again, which is kind of annoying.
How do I avoid such things?
Any tips and tricks?
In case you're still working on this, check out PSTCollectionView. It works exactly like UICollection view but supports backwards of iOS 4.3.
Its difficult to answer without knowing why you need to create a custom view similar to the tableview. If you have a developer account you might want to check the new iOS 6 view based on tableview. Not sure if I can talk more about it as it is under NDA.
For the UIImage fading, how about flagging each UIImage as displayed and then do a check when reloading the data or recalling the fade statement. Only fade the images that are not flagged as already presented?
In new iOS 6.0 there is new controllers call UIContainer view,its similar to UITableview but we can also set more then one column with that.
delegate methods for that controllers are almost same as in UITableview.you can use that controller if you have similar requirements.
do anyone have experience with UITableView inside a custom UITableViewCell ?
I had a try and the UITableView in the UITableViewCell looks like that can't respond to user inputs (i.e scrolling).
Before going any further I would like to know if I am wasting my time !
Does anyone have seen something like that around ? Any reference would be helpful.
Thanks
I haven't done this, but I discourage this. This could cause odd things to happen.
In a similar vein, Apple says not to use UIWebView inside of a UIScrollView. The reason is because a web view is a subclass of the scroll view. Nesting them can cause unexpected behaviors. Note that the table view is also a subclass of the scroll view. While Apple doesn't explicitly mention your case, I assume that it is the same idea.
If yo must, subclass UITableViewCell and see what happens. It's not that difficult. Make the cell implement the UITableViewDelegate protocol.
Since the parent TableView responds to the vertical swipe gesture, your child TableView is not going to ever see it. Where should the swipe gesture "go"? It has to go one place or the other, so one of the TableViews will always not behave "correctly". I do think that trying to put a TableView inside a TableViewCell and getting it to work just like a root TableView is probably a waste of time.
How do you know that you scrolled using the UITableViewIndex ?
I have some basic info to show on my cells, and when I jump/scroll I need to retrieve info about thoses cells by a request for a group(page) of items.
So in order to request only thoses I've stopped to, I need a way to know that I've stopped scrolling (I used scrollViewDidEndDecelerating) but with the UITableViewIndex we ca just jump to another index or scroll though them.
The only feedback that you get is in the UITAbleViewDelegate protocol - none of these report that the table view has scrolled.
However, you will get calls to tableView:cellForRowAtIndexPath: calls to your data source - this will tell you that the table view has moved enough to want a new cell.
Also, you have the visibleCells property of the UITableView itself to see where you are in the table?
It might help if you put more detail into your question - why do you need to know that a scroll has happened?
The UITableView inherits from UIScrollView so you can also implement the UIScrollViewDelegate methods such as scrollViewDidScroll. When the table view scrolls, these will be called.
However, if you explain why you need to know whether the table view has scrolled, there might be a better answer.
Edit:
From your updated question, it's still not totally clear whether you need the scrollview delegate methods.
If you just need to update the contents of the cells themselves, put that in cellForRowAtIndexPath and the table view will automatically call it when the cell comes into view.
If you need to update something outside the table view, you might still be able to do it in cellForRowAtIndexPath or you can handle scrollViewDidEndDecelerating: and then use the table view's visibleCells or indexPathsForVisibleRows methods to get the list of cells currently visible.
I have a series of UIViews inside a UIScrollView, and the UIViewControllers for those views are not receiving the touch events. If I take the views out of the scroll view then it works.
I have enabled userInteraction on the views but it's still not working!
This must be possible and I'd be really grateful if someone could point me in the right direction!
Thanks,
Mike
Do the views have their own touch handlers, or are you relying on the viewcontroller to get the touches? Depending on how you have set things up, the views may be handling the touches without passing through to the view controller.
I have overcome this issue by overriding the loadView method of the view controller, and setting the view's instance variable to a simple UIView subclass which passes on the touches.
Check what you are returning in scrollview delegate method view for scrollin in scroll view.
As mahboudz mentioned - check if you have any custom handler for touch event. If not, please have one. Its far more relief to do whatever you want to do with your view. Check out Apples sample app from scrollViewSuite. They have tapDetectingImageView delegate. I used the same in my app it worked great! Hope this helps!
You may find this post useful. It's an example of a pretty clean way of intercepting events.
Have touch handlers for view for which you want to receive touch events and that will work.