UITextField resigns first responder when scrolling in UITableView isn't fast enough - ios

I have a uitableview where each cell has a uitextfield. If i touch a text field low down in the table view, then it sets the text field as first responder and scrolls to it, and also scrolls up a keyboard (all as expected). But if the keyboard animation is faster than the table view scrolling, then the keyboard momentarily covers up the text field, which then therefore resigns as first responder.
It's hard to reproduce with a basic project or any code snippet that i could paste here, because the problem is that each cell is doing a lot of layout, and it's dequeueing other cells as it scrolls up etc, meaning that the scrolling is fairly slow.
I don't mind the slightly jerky scrolling, i'm just interested in finding a way of ensuring the text field keeps itself as first responder even when it momentarily is hidden by the keyboard.
edit:
as in the answer below, i'm now trying to maintain whether or not the table view is scrolling, and only allow resigning of first responder if scrolling = NO. The code for UITableViewDelegate is below, but the problem now is that non animated movements of the table view (i.e. scrollToRowAtIndexPath...animated:NO) result in scrollViewDidScroll, but not scrollViewDidEndScrollingAnimation. Any ideas on how to get round this in a way that isn't even more clunky?
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
NSLog(#"YES");
self.scrolling = YES;
}
-(void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{
NSLog(#"NO");
self.scrolling = NO;
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
NSLog(#"NO");
self.scrolling = NO;
}
- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView
{
NSLog(#"NO");
self.scrolling = NO;
}

You could subclass UITextField and implement
- (BOOL)resignFirstResponder
There you could return NO while scrolling.

Related

UITableView, make footer not bounce when table view scrolled till the end

When I scroll to the bottom of my table view, the last element (intended to be a footer) bounces with the tableview object.
Is there a way I can make this last item / footer item, pin to the bottom of the screen when it is reached?
You can use below Method, in this way, when you go down in UITableView ,
at that time Stop or turn off bouncing all together?
e.g. .bounces=NO; .alwaysBounceVertical=NO
otherwise Set Yes To all.
this way may be helpful to you.
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
NSLog(#"scrollView.contentOffset.y-%f",scrollView.contentOffset.y);
NSLog(#"tblView.contentSize.height=%f",tblView.contentSize.height-tblView.frame.size.height);
if ([scrollView isKindOfClass:[UITableView class]])
{
if(scrollView.contentOffset.y == tblView.contentSize.height-tblView.frame.size.height)
{
// we are at the end
//Sp do wahtever want to do here.
//set bounce no
}
else
{
//not at END.
//set bounce Yes
}
}
}

How to animate views according to tableview scrolling directions without content scrolling

i'm trying to implement a specific tableview behaviour (Like on Facebook app).
I want to have a dynamic header that will be magnified every time the user scrolls up and will be shrieked when the user scroll down.
In addition i want the tableview to cause the effect of pushing the header and than scrolling the tableview cells.
I used the method:
- (void)scrollViewDidScroll:(UIScrollView *)aScrollView
in this method i calculated the offset and the direction and called a method that shrink or magnify the header accordingly
so far so good.
The thing is that the animation is being performed with the tableview scrolling.
To avoid it, I created a custom scrollview on to of the top of my tableview, I taged the two scrollviews differently.
In the scrollview i created a weak reference of the tableview and a boolean value that indicated if the scrollview should return the tableview touch.
When the shrinking\magnifying animation was finished i changed the boolean value so it will signal the custom scrollview to return the tableview in my HitTest methods that i implemented inside the scrollview.
But hitTest not called when the user keep scrolling (without leafing the finger), in additions now my buttons inside my tableViewCell aren't reacting.
Here is my HitTest Method:
- (UIView*)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{
UIView* result = [super hitTest:point withEvent:event];
if (_recieveTouchOnTable)
{
return _table;
}
else
return result;
}
Here is my scrollViewDidScroll method:
(onProgress means that the animation is being performed, so keep returning the custom scrollview)
Tag = 2 = the custom scrollview
Tag = 1 = the tableview
- (void)scrollViewDidScroll:(UIScrollView *)aScrollView {
CGFloat yVelocity = [aScrollView.panGestureRecognizer velocityInView:aScrollView].y;
CGFloat offset = lastCustomScrollViewContentOffset.y-aScrollView.contentOffset.y;
lastCustomScrollViewContentOffset =aScrollView.contentOffset;
if (yVelocity<0)
offset = fabs(offset)*-1;
else if(yVelocity>0)
offset = fabs(offset);
if (offset!=0 && aScrollView.tag == 2)
[self layoutViewAccorrdingToTableviewScorlingVelocity:offset];
if (!onProgress ){
customScrollView.recieveTouchOnTable=YES;
}
}
Am i missing something, or maybe there's a more simple way to do it?

UICollectionView Within Last UITableViewCell AND Congruent Scrolling? How?

I'm racking my head over this one, I know this has to be possible but after going over every bit of documentation I still can't come up with something that works well.
Basically, I have a UICollectionView in the LAST cell of a UITableView. What I want to happen is, only when the UITableView is totally scrolled to the bottom, can the UICollectionView in it's last cell start scrolling. And, if the TableView offset reaches the bottom of the CollectionView's tableviewcell during a drag / pan, any additional dragging of the current table view drag / pan should effect the collection view instead of the table view.
Also, when the collection view is scrolling, if a user starts scrolling on the collection view, if the collection view reaches the top of it's scroll (Content Y offset of 0 or less), and additional scrolling of the current pan/drag gesture in affect should cause the containing table view to scroll up.
The reason I want to achieve this effect, is because the table view cell above the last cell containing the collection view, contains a UISegmentControl that toggles the contents of the UICollectionView, and I want the user to be able to toggle this segment at any time while scrolling in the CollectionView. Meaning the collection view has to scroll but the parent table view needs to not scroll..
I've tried playing with the gesture recognizers, and doing something with
– gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer:
This gets me halfway there, I can use a flag to return yes/no to this method if the collection view is to scroll into a negative offset (Past it's top offset) or if the table view has reached the end of it's total scroll.. I get sort of close to what I want to achieve, but if I scroll up slowly on the collection view, it doesn't fire the simultaneous recognizer, same happens if I scroll down on the table view too slowly.
Another issue is, I do NOT want the collection view to bounce. However setting bounces to NO totally prevents the simultaneous recognizer to fire at all. I even tried setting content offset to CGPointZero on the collection view in it's viewDidScroll if it's y offset were to dip below zero. This also doesn't work and prevents the simultaneous method from firing...
Does anyone have any idea what to do? Or something to point me in the right direction?
UPDATE -
Still trying at this, I've made little progress towards the behavior I'm trying to achieve. I've messed with toggling userInteractionEnabled in the viewDidScroll method, as have I tried in willBeginDragging. The same with scrollEnabled property.. No luck :( I get a behavior similar to what I want with this, however the parent view will not scroll up until the user lets off the screen and attempts to scroll again..
UPDATE -
Is there anyway to transition the panGestureRecognizer currently handling scroll events DURING scrolling? If I could transition the scroll handler from the child to the parent while still scrolling this would solve my issue. I've looked through apple's gesture related and uiscrollview related documentation and can't find anything close to doing that.
UPDATE -
Just got done trying something like this..
- (CGPoint)maxParentContentOffset
{
return CGPointMake(0, self.parentScrollView.contentSize.height - self.frame.size.height - 44);
}
- (void)parentScrollViewDidScroll:(UIScrollView *)parentScrollView
{
if (self.contentOffset.y > 0) {
self.parentScrollView.contentOffset = [self maxParentContentOffset];
}
}
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
if (scrollView.contentOffset.y < 0) {
scrollView.contentOffset = CGPointZero;
}
}
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
CGPoint translation = [scrollView.panGestureRecognizer velocityInView:scrollView.superview];
if (translation.y < 0) {
[UIView animateWithDuration:0.5f animations:^(void) {
self.parentScrollView.contentOffset = [self maxParentContentOffset];
}];
}
}
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
return YES;
}
However there is a problem... for some reason I keep getting a bad access error on the following method
- (void)parentScrollViewDidScroll:(UIScrollView *)parentScrollView
{
if (self.contentOffset.y > 0) {
self.parentScrollView.contentOffset = [self maxParentContentOffset];
}
}
Specifically setting the content offset. Which is really strange, because with breakpoints I'm seeing parentScrollView and self as being set. I'm wondering if it's not a bad access but it's getting trapped in an infinite loop for some reason? Any ideas?
Even though you may manage to make it work now, embedding a collection view inside a table view (both UIScrollView subclasses) is not a good idea and it will bug as soon as apple modifies their implementation.
Try to migrate to a single UICollectionView layout. After all there's nothing you can't achieve with a collection view that a table view can.
Separate your "table view" and "collection view" in two (or more) collection view sections, then implement layoutAttributesForItemAtIndexPath: differently according to the indexPath.section.
To make it table view-like you'll want to return frames whose width are the same as the collection view.
If your layout is simpler then you could use a UICollectionViewFlowLayout (maybe your already are) and implement collectionView:layout:sizeForItemAtIndexPath: as described above.
Figured this out after a good 8 hours.. I had a confliction due to infinite setting of the parent scroll view offset, since I had multiple objects that were of the same class that received a call whenever their parent view scrolled, both trying to set the same parent view offset to zero, which caused the other class to see scroll changing, and calling their method to change offset, and the process happening infinitely causing a crash.
This code however, solved everything and functions exactly as I was desiring. Hopefully this helps anyone else in the future looking to get congruent scrolling between a parent and child scroll view.
- (CGPoint)maxParentContentOffset
{
return CGPointMake(0, self.parentScrollView.contentSize.height - self.frame.size.height - 44);
}
- (void)parentScrollViewDidScroll:(UIScrollView *)parentScrollView
{
if (self.contentOffset.y > 0 && self.isDragging) {
self.parentScrollView.contentOffset = [self maxParentContentOffset];
}
}
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
if (scrollView.contentOffset.y < 0) {
scrollView.contentOffset = CGPointZero;
}
}
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
CGPoint translation = [scrollView.panGestureRecognizer velocityInView:scrollView.superview];
if (translation.y < 0) {
[UIView animateWithDuration:0.5f animations:^(void) {
self.parentScrollView.contentOffset = [self maxParentContentOffset];
}];
}
}
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
return YES;
}
In an application that I've worked, we needed something close to that, we wanted to have a uitableview inside the first cell of another uitableview, which should be scrollable (you can check the app here)
Our approach was quite different, and we thought about doing it your way, but that way was a bit overkill for the time we had, and needed too much custom control instead of using what apple already gives us.
I'll share our method just for you to have another way to solve your problem, since I can't figure out what is wrong in that method call.
On the outer tableview's datasource lifecycle, we were able to know how our inner table view would be, allowing us to feed our inner table view with all the data, which would then gave us the total content size of the inner table view.
With this info, and since we knew (and in your case, you know) the actual cell where the inner table view would be placed, we make that cell's height equal to the height of the inner tableview content size. With this, the inner table view is 'totally visible'(in your case, the collection view) inside the outer table view cell, but since the cell is so big, it looks like we are scrolling the inner table view when we are simply scrolling a really big, special, cell.
And it won't bounce, if you don't want it too.
In our case, this worked, and the implementation was pretty straight forward.
In your case, and since you have a UISegmentedController, you should do a beginUpdates endUpdates and a 'reloadData', upon press in the UISegmenedController, in your outer table view in order to be able to recalculate the collection view's content size and resize the last cell, but that is pretty straight forward.
I know I'm not answering your question, but this method allowed us to achieve something so similar in such a fast and straight forward way that I thought it was worth sharing.
Hope it helps.

Newly added tableview cells are hidden upon bounce back

I have a UITableview that is populated by a REST web service. I have bouncing enabled so that I can trigger a call to the server with
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
Using this method the call gets triggered when the user lifts their finger after trying to scroll past the bottom of the tableView. The view then bounces back and the new cells are added. The problem I have is that it is not obvious anything was added. The tableView bounces back to the bottom of the screen and it isn't until the user tries to scroll again that the new cells become visible. Here is the method I use to trigger the call.
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{
NSInteger currentOffset = scrollView.contentOffset.y;
NSInteger maximumOffset = scrollView.contentSize.height - scrollView.frame.size.height;
if (maximumOffset - currentOffset <= -40)
{
if (scrollView == _feedTableView)
{
//This method has a call to the server and adds the new cells to the table
[self loadFeed:feedRefreshControl];
}
}
}
I tried turning off bouncing after the trigger in an attempt to get the bottom cell to remain where it was when the user lifts their finger but the last cell just shoots back to the bottom in an non-animated way.
Any ideas would be appreciated!
In the past, I've used a fake last cell which held a spinner. As the user scrolls down to the end of the list, they see the spinner cell as the last cell. When more data is added the spinner cell gets replaced with the first cell of the new data. This is an obvious visual clue to the user that more information has been loaded into the list. I also flashed the status bar, again just a visual cue to the user that the data has been updated.

Make Keyboard Disappear when UITableView Scrolls

I have a UITextField at the top of my Table View, after the text field is selected I want the keyboard to disappear. I know to call [[self view] endEditing:YES]; but I don't know how to check for the scroll. A good example of this is IMessage, when the keyboard is in view you can scroll up to collapse it, I want my table view to work inversely.
UITableView is a subclass of UIScrollView. By being the table delegate (implementing <UITableViewDelegate>) you are also the scroll view delegate (<UIScrollViewDelegate>) and as such you can implement:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
Then you will receive a notification whenever the table view is scrolled. You can then also use scrollView.contentOffset to check where the table has scrolled to (which direction it's scrolling in).
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
[textField resignFirstResponder];
}
Try other method in UIScrollViewDelegate if you need other behaviour.
Call resignFirstResponder where appropriate.
It seems you use UITextField in your cells. Use UITextFieldDelegate protocol to know when UITextField ends being edited:
-(void)textFieldDidEndEditing:(UITextField*)textField
{
[textField resignFirstResponder];
}

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