I've been struggling with this issue for days, so I hope someone can help me out...
I have a grouped UITableView with several cells. I want to draw some custom graphics above the UITableView that would scroll with the content of the table. Specifically, I want to draw a line with dots, joining the UITableViewCells (across the sections) like this:
Of course if we have more cells than what the screen is capable of displaying, the upper layer with the custom drawing should move with the underlaying cells.
I've tried to subclass UITableView and override it's -drawRect method, but it didn't work. Even if I wouldn't call [super drawRect:rect], the table content displayed without problem.
I've tried to add a new subview to the UITableView, but it changes it's size dynamically when it gets the cells and sections from its datasource... I'm out of ideas...
Although the Web is full of custom UITableViewCell samples, I haven't managed to find anything similiar to my concept...
Can anyone help me how to achieve the above mentioned feature?
First your should subclass UITableView. Then create another UIView and add it as a subView of your custom UITableVIew.
Next override the contentOffset property of the UITableView.
-(void)setContentOffset:(CGPoint)contentOffset
{
[super setContentOffset:contentOffset];
// Custom code here. Update custom subview here.
}
This method will be called as the UITableView is scrolled. You can then adjust the offset of your subview and update its drawing.
Related
How do I go about getting the correct frame (and more importantly, origin) of a UIButton that is outside of the current visible area of a UIScrollView? It seems like when they are not visible, I get erroneous values (i.e. I layout a subview using the frame values I receive, and when I scroll down to it, it is in the wrong place.) Any ideas?
Once again, I've answered my own question. If you have outlets and/or references to your buttons, you'll want to re-reference your button/label/custom view frames in the scrollViewDidScroll method. In my case, I was trying to line up a custom view frame with a button frame, so the implementation looks like this:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
// Enumerate through each object you're looking to reposition and compare them:
if(!(CGRectEqualToRect(bsv.frame, btn.frame))) bsv.frame = btn.frame;
I hope this will help someone out there.
Imagine, there is a UIViewController with a UIScrollView in it. At the top of the view there is an UIImageView, some UILabels and other things. Furthermore, there is a UITableView which content is Dynamic Prototypes. I attach a picture to make it clear:
I haven't got a static amount of cells in the UITableView so it could be scrollable. My problem is the following: the UITableView scrolls in itself but I want to scroll the whole View. What is the best possibility to do that?
Possible solutions I've founded today
1) The first thing is: I create a UITableViewController and declare a header section in which I include all my labels, images etc. programmatically (I would love to use the interface builder for that...)
2) Another solution is to calculate the height of the view. I tried the best to do it like this way - but: without success. If this is the best way to do that: Can anybody give an example?
I would ditch the UIScrollView and just use a UITableView. You can add a UIView object as the tableHeaderView of the UITableView just by dragging it in in Interface Builder. Now since everything is part of the UITableView hierarchy, everything will scroll together as expected.
You could also try setting delaysContentTouches to NO on your scrollView. Depending on your setup, this may make the scroll view respond to the touch first instead of the table view.
From Apples UIScrollView Docs:
delaysContentTouches
A Boolean value that determines whether the scroll view delays the
handling of touch-down gestures.
#property(nonatomic) BOOL delaysContentTouches
Discussion
If the value of this property is YES, the scroll view delays handling
the touch-down gesture until it can determine if scrolling is the
intent. If the value is NO , the scroll view immediately calls
touchesShouldBegin:withEvent:inContentView:. The default
value is YES.
You'll have to (as you've mentioned) add the UIView containing the image and buttons to the actual UITableView. Embedding it in the scroll view will produce the undesired behavior that you're seeing.
I would recommend returning the UIView as the header view for the first section of your table view. You can do this by implementing the UITableViewDelegate method:
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section;
If you maintain an IBOutlet to the view containing your image/labels, you can return it here.
this is same demo i hope its helps you from iphone sorce code library
http://developer.apple.com/library/ios/#samplecode/iPhoneCoreDataRecipes/Introduction/Intro.html
thank you
I am trying to have a UI component stuck to my cells in a UITableView and scrolling with them...
It seems weird but a picture permits to understand the main point:
Before Scrolling
During Scroll
I am trying to do the same effect but with other UI components (another UIVIew).
Do you have some hints to do this ?
Is it a custom uitableviewcell inserted at start ?
Is there an easy-to-implement hack ?
Thanks a lot for your help !
You can add any UIView and make it scroll with the table cells by placing the UIView in the table header. There is a special property for a table view, called tableHeaderView.
Use something like this:
UIView* my_custom_view;
// TODO: Alloc, and initialize the view
tableView.tableHeaderView = my_custom_view;
I'm working on an an app that updates both a UITableView and a UIScrollView. I like how UITableView updating works. As I add, remove, or update items, I call insertRowsAtIndexPaths:withRowAnimation:, reloadRowsAtIndexPaths:withRowAnimation:, and deleteRowsAtIndexPaths:withRowAnimation: as appropriate. However, updating the UIScrollView has turned out to be more of a challenge.
So how can I do it? My UIScrollView contains images, and I want to be able to insert, update, and remove individual images -- with animation -- efficiently and smoothly, and perhaps in random order. How does one do this sort of thing?
As an example, I have code like this in my UIScrollViewDelegate implementation for adding a new image:
if (newImageindex == currentImageIndex) {
[scrollView setNeedsDisplay];
[scrollView setContentOffset:portalView.contentOffset animated:YES];
} else if (newImageIndex < currentImageIndex) {
currentImageIndex++;
CGPoint offset = portalView.contentOffset;
offset.x += portalView.frame.size.width;
portalView.contentOffset = offset;
}
This is close, I think, but not quite right. I end up with the images added, but the UIScrollView seems to scroll to a position before the first image in the view. If I start scrolling it by hand, the first image appears. It's like it's scrolled to position -1 in my images.
The example may not help to highlight my problem much, but surely it's a common need to dynamically rejigger the images appearing in a UIScrollView. What's the state of the art on this?
A UIScrollView is not so specialized and structured as a UITableView. The former is a generic view that scrolls and zooms anything you put in it, and you can put any subviews into it anywhere, whereas the latter is made especially to display lists of cells stacked on top of each other.
So the answer is: you need to animate the subviews in the scrollview yourself. There are various libraries like Three20 which provide frameworks for creating more advanced views, you'll need to use a suitable component from one of those or roll your own.
I have a UITableView which is a subview of a UIView, then that UIView is a subview of a UIScrollView. How do I detect the touches that should scroll the UITableView?
The UITableView can get item selection events (a cell in the table is selected/tapped) just fine, except that you have to hold down on the cell before it fires. But I can't get the UITableView to scroll, its always the UIScrollView that reacts to the pan gesture.
Any help is greatly appreciated. Thanks in advance!
EDIT:
Solved, though I asked the wrong question. It does work by default as Roman K pointed out. I think the problem was related to having a part of the UITableView outside the bounds of the UIScrollView (the UITableView went over the bottom bounds of the UIScrollView). Setting it to correctly fit inside the UIScrollView fixed it.
Please, make sure that UIScrollView's properties delaysContentTouches and canCancelContentTouches are set appropriately. They control how UIScrollView instance passes touch information to its subviews. By default delaysContentTouches is set to YES. Also, make sure that, if you extended UIScrollView, touchesShouldBegin:withEvent:inContentView: allow touches in the subview.
Otherwise, UITableView scrolling should work by default in your scenario. If you create a test project with just the view hierarchy as described you will see that it is the case. So, compare the two and see what difference affects the scrolling.