How to disable a UITableView from scrolling up vertically? - objective-c

I'm using EGORefreshTableHeader in conjunction with a static cell (defined in a nib) in a UITableView.
I'd like to be able to scroll the tableview down to trigger the EGORefreshTableHeader and thus refresh the data in the static cell. BUT, as the static cell is sized to fit perfectly in the window, I want to prevent folks from being able to scroll up.
Is there a way to do this?

Try this:
CGFloat a;
-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
a = scrollView.contentOffset.y;
}
-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
if (scrollView.contentOffset.y > a)
{
[scrollView setScrollEnabled:NO];
[scrollView setContentOffset:CGPointMake(0, a)];
}
[scrollView setScrollEnabled:YES];
}

Related

Tracking frame.origin.x in UIPageController while scrolling

I'm using standard UIPageViewController here and I need to track x coordinate in order to change the alpha of the image accordingly. I try to find the UIScrollView in UIPageViewController like this and it works:
for (UIView *view in self.pageViewController.view.subviews) {
if ([view isKindOfClass:[UIScrollView class]]) {
[(UIScrollView *)view setDelegate:self];
}
}
But when I do this:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
MTWPageContentViewController *pageContentVC = [self viewControllerAtIndex:_mainPageControl.currentPage];
NSLog(#"%f", pageContentVC.view.frame.origin.x);
}
NSLog gives me 0.000 which obviously means that I'm doing something wrong.
pageContentVC exists and it is the view controller visible at the moment I scroll.
So, tell me how do I track x coordinate of UIPageViewController's subview while scrolling?
You can grab the gesture recognisers from the UIPageViewController and add yourself as a target/action to get information about the pan.
for (UIGestureRecognizer *gestureRecognizer in self.pageViewController.gestureRecognizers) {
if ([gestureRecognizer isKindOfClass:UIPanGestureRecognizer.class]) {
[gestureRecognizer addTarget:self action:#selector(panned:)];
}
}

The UICollectionView "swipe-away" in iOS7 app manager?

On any 2014+ iPhone or iPad, double-click the home button to see the "app manager"
This is a left-right UICollectionView BUT it has a "swipe-away" gesture .. swipe up. How is it done? It's not so easy to "remove" a cell from a UICollectionView.
Footnote for googlers .. for the general problem of "peeling off", "tearing away", one cell from a collection view, here's a full tidy explanation: https://stackoverflow.com/a/24339705/294884 Hope it helps someone.
It can be much simpler than the comments on your question are suggesting.
Your cell should contain a view (the thing that you're going to drag off) and you add a UIPanGestureRecognizer to that view.
In the gesture's action method, you move the view up or down, and when it gets far enough off that you want to delete it, you just animate it off. There are plenty of questions here dealing with this part.
This leaves a gap in your collection and now you need to move things around. It turns out this is quite simple:
[_collectionView performBatchUpdates:^{
[_collectionView deleteItemsAtIndexPaths:#[indexPath]];
} completion:^(BOOL finished) {
// you might want to remove the data from the data source here so the view doesn't come back to life when the collection view is reloaded.
}];
The stuff to the right of the removed cell slides over and we're all good.
Another problem to get over: making sure your gesture recognizer and the collection view's one play nice together. Thankfully, that's not too tricky either.
[_collectionView.panGestureRecognizer requireGestureRecognizerToFail:pgr]; //where pgr is the recognizer you made for dragging the view off
This means in order for the collection view's pan gesture to do its thing, your one has to fail. So you'll want to set yours up so that it only works when panning up and down, and let the collection view still do its thing for left to right pans. In your gesture recognizers's delegate, implement the following method which simply checks if you're moving more on the x-axis or y-axis.
-(BOOL)gestureRecognizerShouldBegin:(UIPanGestureRecognizer *)gestureRecognizer
{
CGPoint translation =[gestureRecognizer translationInView:self.view];
return(translation.x * translation.x > translation.y * translation.y);
}
I was looking for this functionality and using #mbehan suggestion i faked this functionality using UICollectionView.
What i did is i added a view of smaller size on a collection cell(Transparent background) and added a single pan gesture on CollectionView(not on each cell) then on pan gesture i move the view and it looks like the cell is moving. After view reaches some point i first hide it and then deletes the collection view cell.
Cell Hierarchy : collectionViewCell -> View(tag value==2) -> UILabel(tag Value == 1)
Label is just used for placeholder purpose.
i am posting my code below:
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *cell = (UICollectionViewCell *)[collectionView dequeueReusableCellWithReuseIdentifier:#"Cards" forIndexPath:indexPath];
UILabel *lblNumber = (UILabel*)[cell.contentView viewWithTag:1];
UIView *viewTouch = (UIView*)[cell.contentView viewWithTag:2];
[viewTouch setHidden:NO];
[lblNumber setText:arrCards[indexPath.row]];
return cell;
}
- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section {
return UIEdgeInsetsMake(0, 50, 0, 30);
}
-(BOOL)gestureRecognizerShouldBegin:(UIPanGestureRecognizer *)gestureRecognizer
{
if([gestureRecognizer isEqual:panGesture]) {
CGPoint point = [(UIPanGestureRecognizer*)gestureRecognizer translationInView:collectionView_];
if(point.x != 0) { //adjust this condition if you want some leniency on the X axis
//The translation was on the X axis, i.e. right/left,
//so this gesture recognizer shouldn't do anything about it
return NO;
}
}
return YES;
}
- (IBAction)panGestureCalled:(UIPanGestureRecognizer *)sender {
yFromCenter = [sender translationInView:collectionView_].y; //%%% positive for up, negative for down
UIView *view = sender.view;
CGPoint location = [view.superview convertPoint:view.center toView:collectionView_];
NSIndexPath *indexPath = [collectionView_ indexPathForItemAtPoint:location];
UICollectionViewCell *cell = [collectionView_ cellForItemAtIndexPath:indexPath];
UIView *touchView = (UIView*)[cell.contentView viewWithTag:2];
switch (sender.state) {
case UIGestureRecognizerStateBegan:{
originalPoint = touchView.center;
break;
};
case UIGestureRecognizerStateChanged:{
touchView.center = CGPointMake(originalPoint.x , originalPoint.y + yFromCenter);
break;
};
//%%% let go of the card
case UIGestureRecognizerStateEnded: {
CGFloat velocityY = (0.2*[(UIPanGestureRecognizer*)sender velocityInView:collectionView_].y);
if (velocityY < -30 && yFromCenter<0) {
[self hideView:touchView withDuration:0.2 andIndexPath:indexPath];
}else if ((yFromCenter< 0 && yFromCenter > -200) || yFromCenter > 0){
CGFloat animationDuration = (ABS(velocityY)*.0002)+.2;
[self resettleViewToOriginalPosition:touchView andDuration:animationDuration];
}else
[self hideView:touchView withDuration:0.2 andIndexPath:indexPath];
};
break;
case UIGestureRecognizerStatePossible:break;
case UIGestureRecognizerStateCancelled:break;
case UIGestureRecognizerStateFailed:break;
}
}
-(void)resettleViewToOriginalPosition:(UIView*)view andDuration:(float)duration{
[UIView animateWithDuration:duration
delay:0.0f
options: UIViewAnimationOptionCurveEaseOut
animations:^
{
[view setCenter:originalPoint];
}
completion:^(BOOL finished)
{
}];
}
- (void)hideView:(UIView*)view withDuration:(float)duration andIndexPath:(NSIndexPath*)indexPath
{
[UIView animateWithDuration:duration
delay:0.0f
options: UIViewAnimationOptionCurveEaseOut
animations:^
{
CGRect frame = view.frame;
frame.origin.y = -300;
view.frame = frame;
}
completion:^(BOOL finished)
{
[view setHidden:YES];
CGRect frame = view.frame;
frame.origin.y = 39;
view.frame = frame;
NSLog(#"View is hidden.");
[arrCards removeObjectAtIndex:indexPath.row];
[collectionView_ performBatchUpdates:^{
[collectionView_ deleteItemsAtIndexPaths:#[indexPath]];
} completion:^(BOOL finished) {
// you might want to remove the data from the data source here so the view doesn't come back to life when the collection view is reloaded.
}];
}];
}
and keep pagingEnabled of CollectionView to NO and then it should be good to go.

UITableViewCell content overlaps delete button when in editing mode in iOS7

I am creating a UITableView with custom UITableViewCells. iOS 7's new delete button is causing some problems with the layout of my cell.
If I use the "Edit" button, which makes the red circles appear I get the problem, but if I swipe a single cell it looks perfect.
This is when the Edit button is used:
[self.tableView setEditing:!self.tableView.editing animated:YES];
This is when I swipe a single cell:
As you can se my labels overlaps the delete button in the first example. Why does it do this and how can I fix it?
try using the accessoryView and editingAccessoryView properties of your UITableViewCell, instead of adding the view yourself.
If you want the same indicator displayed in both editing and none-editing mode, try setting both view properties to point at the same view in your uiTableViewCell like:
self.accessoryView = self.imgPushEnabled;
self.editingAccessoryView = self.imgPushEnabled;
There seems to be a glitch in the table editing animation in IOS7, giving an overlap of the delete button and the accessoryView when switching back to non-editing state. This seems to happen when the accesoryView is specified and the editingAccessoryView is nil.
A workaround for this glitch, seems to be specifying an invisible editingAccessoryView like:
self.editingAccessoryView =[[UIView alloc] init];
self.editingAccessoryView.backgroundColor = [UIColor clearColor];
The problem is that in edit mode the cell's contentView changes in size. So either you have to override layoutSubviews in your cell and support the different frame sizes
- (void) layoutSubviews
{
[super layoutSubviews];
CGRect contentFrame = self.contentView.frame;
// adjust to the contentView frame
...
}
or you take the bait and switch to autolayout.
First I thought setting contentView.clipsToBounds to YES could be an ugly workaround but that does not seem to work.
I've resolved this problem with set up constraints without width only leading and trailing
As tcurdt mentioned, you could switch to autolayout to solve this issue. But, if you (understandably) don't want to mess with autolayout just for this one instance, you can set the autoresizingMask and have that turned automatically into the appropriate autolayout constraints.
label.autoresizingMask = UIViewAutoresizingFlexibleWidth;
Just use this method in your custom TableViewCell class you can get the perfect answer,
Here self is UITableviewCell
- (void)layoutSubviews {
[super layoutSubviews];
for (UIView *subview in self.subviews) {
for (UIView *subview2 in subview.subviews) {
if ([NSStringFromClass([subview2 class]) isEqualToString:#"UITableViewCellDeleteConfirmationView"]) { // move delete confirmation view
[subview bringSubviewToFront:subview2];
}
}
}
}
And if any one want to adjust the Delete Button Size, Use the following Code
- (void)layoutSubviews {
[super layoutSubviews];
for (UIView *subview in self.subviews) {
for (UIView *subview2 in subview.subviews) {
if ([NSStringFromClass([subview2 class]) isEqualToString:#"UITableViewCellDeleteConfirmationView"]) { // move delete confirmation view
CGRect rect = subview2.frame;
rect.size.height = 47; //adjusting the view height
subview2.frame = rect;
for (UIButton *btn in [subview2 subviews]) {
if ([NSStringFromClass([btn class]) isEqualToString:#"UITableViewCellDeleteConfirmationButton"]) { // adjusting the Button height
rect = btn.frame;
rect.size.height = CGRectGetHeight(subview2.frame);
btn.frame = rect;
break;
}
}
[subview bringSubviewToFront:subview2];
}
}
}
}
Best way to remove this problem is that add an image in cell and set it in Backside.
UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"bgImg.png"]];
imageView.frame = CGRectMake(0, 0, 320, yourCustomCell.frame.size.height);
[yourCustomCell addSubview:imageView];
[yourCustomCell sendSubviewToBack:imageView];
If your text would overlap the delete button then implement Autolayout. It'll manage it in better way.
One more case can be generate that is cellSelectionStyle would highlight with default color. You can set highlight color as follows
yourCustomCell.selectionStyle = UITableViewCellSelectionStyleNone;
Set your table cell's selection style to UITableViewCellSelectionStyleNone. This will remove the blue background highlighting or other. Then, to make the text label or contentview highlighting work the way you want, use this method in yourCustomCell.m class.
- (void)setHighlighted:(BOOL)highlighted animated:(BOOL)animated
{
if (highlighted)
self.contentView.backgroundColor = [UIColor greenColor];
else
self.contentView.backgroundColor = [UIColor clearColor];
}
I hope you understand it in a better way.
Bringing to front UITableViewCellDeleteConfirmationView in the layoutSubviews of the custom cell works for me on iPhone, but not on iPad.
I have a UITableView in the master part of a splitViewController for the iPad, and in this case
the frame of the UITableViewCellDeleteConfirmationView is (768 0; 89 44), instead of (320 0; 89 44)
So I resize the frame in the layoutSubviews method and this works for me
- (void)layoutSubviews {
[super layoutSubviews];
for (UIView *subview in self.subviews)
{
for (UIView *subview2 in subview.subviews)
{
if ([NSStringFromClass([subview2 class]) isEqualToString:#"UITableViewCellDeleteConfirmationView"])
{
CGRect frame = subview2.frame;
frame.origin.x = 320;
subview2.frame = frame;
[subview bringSubviewToFront:subview2];
}
}
}
}
If you are putting content in the UITableViewCell's contentView, be sure you use self.contentView.frame.size.width and not self.frame.size.width in layoutSubviews.
self.frame expands width in editing mode, and will cause any content on the right to extend past the bounds of the contentView. self.contentView.frame stays at the correct width (and is what you should be using).
Try this: Might be you are setting cell setBackgroundImage in cellForRowAtIndexPath (Delegate Method). Do not set this here. Set your image in:
-(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath { cell.backgroundColor=[UIColor colorWithPatternImage:[UIImage imageNamed:#"cellList.png"]]; }
Enjoy Coding.
My solution is to move whole contentView to the left when Delete button showing:
override func layoutSubviews() {
super.layoutSubviews()
if editingStyle == UITableViewCellEditingStyle.Delete {
var rect = contentView.frame
rect.origin.x = self.showingDeleteConfirmation ? -15 : 38
contentView.frame = rect
}
}

Creating a hidden UISegmentedControl in a UITableView

Like the iBooks app, when you pull down the tableview, a search bar and segmented control appear, to allow you to search and switch between two types of views.
It sticks in that position when you pull down far enough, and alternatively, gets hidden when you pull the tableview up enough.
I am trying to implement the same thing with a UISegmentedControl.
So far I have added a segmented control successfully as a subview to the table. (It has a negative Y frame so make it stick above the tableview).
I have also implemented this code:
- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView {
float yOffset = scrollView.contentOffset.y;
if (yOffset < -70) {
[scrollView setContentOffset:CGPointMake(0.0f, -70.0f) animated:YES];
} else if (yOffset > -10) {
[scrollView setContentOffset:CGPointMake(0.0f, -11.0f) animated:YES];
}
}
This works great, until I try using the segmented control. Where the table will just act like it is scrolling, ignoring the segmented control altogether (i.e. if I tap on a segment, it doesn't even get selected, instead the table scrolls up, hiding the segmented control.
I did use the scrollViewDidScroll method but this made it buggy and the scrolling jumpy.
I also tried to make the segmented control's exclusiveTouch = YES, but this had no effect whatsoever.
I would be thankful for all help! thanks in advance!
Here is my code which works:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
//
// Table view
//
if ([scrollView isKindOfClass:[myTableView class]]) {
//
// Discover top
//
CGFloat topY = scrollView.contentOffset.y + scrollView.contentInset.top;
if (topY <= self.tableHeaderHeightConstraint.constant) {
[self setIsScrolledToTop:YES];
} else {
[self setIsScrolledToTop:NO];
}
}
}
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
//
// Table view
//
if ([scrollView isKindOfClass:[myTableView class]]) {
//
// Toggle favourite category
//
if ([self isScrolledToTop]) {
//
// Show
//
} else {
//
// Hide
//
}
}
}
Edited the above code to make it a bit more generic, but syntactically its correct

How programmatically move a UIScrollView to focus in a control above keyboard?

I have 6 UITextFields on my UIScrollView. Now, I can scroll by user request. But when the keyboard appear, some textfields are hidden.
That is not user-friendly.
How scroll programmatically the view so I get sure the keyboard not hide the textfield?
Here's what worked for me. Having an instance variable that holds the value of the UIScrollView's offset before the view is adjusted for the keyboard so you can restore the previous state after the UITextField returns:
//header
#interface TheViewController : UIViewController <UITextFieldDelegate> {
CGPoint svos;
}
//implementation
- (void)textFieldDidBeginEditing:(UITextField *)textField {
svos = scrollView.contentOffset;
CGPoint pt;
CGRect rc = [textField bounds];
rc = [textField convertRect:rc toView:scrollView];
pt = rc.origin;
pt.x = 0;
pt.y -= 60;
[scrollView setContentOffset:pt animated:YES];
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
[scrollView setContentOffset:svos animated:YES];
[textField resignFirstResponder];
return YES;
}
Finally, a simple fix:
UIScrollView* v = (UIScrollView*) self.view ;
CGRect rc = [textField bounds];
rc = [textField convertRect:rc toView:v];
rc.origin.x = 0 ;
rc.origin.y -= 60 ;
rc.size.height = 400;
[self.scroll scrollRectToVisible:rc animated:YES];
Now I think is only combine this with the link above and is set!
I've put together a universal, drop-in UIScrollView and UITableView subclass that takes care of moving all text fields within it out of the way of the keyboard.
When the keyboard is about to appear, the subclass will find the subview that's about to be edited, and adjust its frame and content offset to make sure that view is visible, with an animation to match the keyboard pop-up. When the keyboard disappears, it restores its prior size.
It should work with basically any setup, either a UITableView-based interface, or one consisting of views placed manually.
Here it is.
(For google: TPKeyboardAvoiding, TPKeyboardAvoidingScrollView, TPKeyboardAvoidingCollectionView.)
Editor's note: TPKeyboardAvoiding seems to be continually updated and fresh, as of 2014.
If you set the delegate of your text fields to a controller object in your program, you can have that object implement the textFieldDidBeginEditing: and textFieldShouldReturn: methods. The first method can then be used to scroll to your text field and the second method can be used to scroll back.
You can find code I have used for this in my blog: Sliding UITextViews around to avoid the keyboard. I didn't test this code for text views in a UIScrollView but it should work.
simple and best
- (void)textFieldDidBeginEditing:(UITextField *)textField
{
// self.scrlViewUI.contentOffset = CGPointMake(0, textField.frame.origin.y);
[_scrlViewUI setContentOffset:CGPointMake(0,textField.center.y-90) animated:YES];
tes=YES;
[self viewDidLayoutSubviews];
}
The answers posted so far didn't work for me as I've a quite deep nested structure of UIViews. Also, the I had the problem that some of those answers were working only on certain device orientations.
Here's my solution, which will hopefully make you waste some less time on this.
My UIViewTextView derives from UIView, is a UITextView delegate and adds a UITextView after having read some parameters from an XML file for that UITextView (that XML part is left out here for clarity).
Here's the private interface definition:
#import "UIViewTextView.h"
#import <CoreGraphics/CoreGraphics.h>
#import <CoreGraphics/CGColor.h>
#interface UIViewTextView (/**/) {
#private
UITextView *tf;
/*
* Current content scroll view
* position and frame
*/
CGFloat currentScrollViewPosition;
CGFloat currentScrollViewHeight;
CGFloat kbHeight;
CGFloat kbTop;
/*
* contentScrollView is the UIScrollView
* that contains ourselves.
*/
UIScrollView contentScrollView;
}
#end
In the init method I have to register the event handlers:
#implementation UIViewTextView
- (id) initWithScrollView:(UIScrollView*)scrollView {
self = [super init];
if (self) {
contentScrollView = scrollView;
// ...
tf = [[UITextView alloc] initWithFrame:CGRectMake(0, 0, 241, 31)];
// ... configure tf and fetch data for it ...
tf.delegate = self;
// ...
NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
[nc addObserver:self selector:#selector(keyboardWasShown:) name: UIKeyboardWillShowNotification object:nil];
[nc addObserver:self selector:#selector(keyboardWasHidden:) name: UIKeyboardWillHideNotification object:nil];
[self addSubview:tf];
}
return(self);
}
Once that's done, we need to handle the keyboard show event. This gets called before the textViewBeginEditing is called, so we can use it to find out some properties of the keyboard. In essence, we want to know the height of the keyboard. This, unfortunately, needs to be taken from its width property in landscape mode:
-(void)keyboardWasShown:(NSNotification*)aNotification {
NSDictionary* info = [aNotification userInfo];
CGRect kbRect = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue];
CGSize kbSize = kbRect.size;
CGRect screenRect = [[UIScreen mainScreen] bounds];
CGFloat sWidth = screenRect.size.width;
CGFloat sHeight = screenRect.size.height;
UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];
if ((orientation == UIDeviceOrientationPortrait)
||(orientation == UIDeviceOrientationPortraitUpsideDown)) {
kbHeight = kbSize.height;
kbTop = sHeight - kbHeight;
} else {
//Note that the keyboard size is not oriented
//so use width property instead
kbHeight = kbSize.width;
kbTop = sWidth - kbHeight;
}
Next, we need to actually scroll around when we start editing. We do this here:
- (void) textViewDidBeginEditing:(UITextView *)textView {
/*
* Memorize the current scroll position
*/
currentScrollViewPosition = contentScrollView.contentOffset.y;
/*
* Memorize the current scroll view height
*/
currentScrollViewHeight = contentScrollView.frame.size.height;
// My top position
CGFloat myTop = [self convertPoint:self.bounds.origin toView:[UIApplication sharedApplication].keyWindow.rootViewController.view].y;
// My height
CGFloat myHeight = self.frame.size.height;
// My bottom
CGFloat myBottom = myTop + myHeight;
// Eventual overlap
CGFloat overlap = myBottom - kbTop;
/*
* If there's no overlap, there's nothing to do.
*/
if (overlap < 0) {
return;
}
/*
* Calculate the new height
*/
CGRect crect = contentScrollView.frame;
CGRect nrect = CGRectMake(crect.origin.x, crect.origin.y, crect.size.width, currentScrollViewHeight + overlap);
/*
* Set the new height
*/
[contentScrollView setFrame:nrect];
/*
* Set the new scroll position
*/
CGPoint npos;
npos.x = contentScrollView.contentOffset.x;
npos.y = contentScrollView.contentOffset.y + overlap;
[contentScrollView setContentOffset:npos animated:NO];
}
When we end editing, we do this to reset the scroll position:
- (void) textViewDidEndEditing:(UITextView *)textView {
/*
* Reset the scroll view position
*/
CGRect crect = contentScrollView.frame;
CGRect nrect = CGRectMake(crect.origin.x, crect.origin.y, crect.size.width, currentScrollViewHeight);
[contentScrollView setFrame:nrect];
/*
* Reset the scroll view height
*/
CGPoint npos;
npos.x = contentScrollView.contentOffset.x;
npos.y = currentScrollViewPosition;
[contentScrollView setContentOffset:npos animated:YES];
[tf resignFirstResponder];
// ... do something with your data ...
}
There's nothing left to do in the keyboard was hidden event handler; we leave it in anyway:
-(void)keyboardWasHidden:(NSNotification*)aNotification {
}
And that's it.
/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{
// Drawing code
}
*/
#end
I know this is old, but still none of the solutions above had all the fancy positioning stuff required for that "perfect" bug-free, backwards compatible and flicker-free animation.
Let me share my solution (assuming you have set up UIKeyboardWill(Show|Hide)Notification):
// Called when UIKeyboardWillShowNotification is sent
- (void)keyboardWillShow:(NSNotification*)notification
{
// if we have no view or are not visible in any window, we don't care
if (!self.isViewLoaded || !self.view.window) {
return;
}
NSDictionary *userInfo = [notification userInfo];
CGRect keyboardFrameInWindow;
[[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] getValue:&keyboardFrameInWindow];
// the keyboard frame is specified in window-level coordinates. this calculates the frame as if it were a subview of our view, making it a sibling of the scroll view
CGRect keyboardFrameInView = [self.view convertRect:keyboardFrameInWindow fromView:nil];
CGRect scrollViewKeyboardIntersection = CGRectIntersection(_scrollView.frame, keyboardFrameInView);
UIEdgeInsets newContentInsets = UIEdgeInsetsMake(0, 0, scrollViewKeyboardIntersection.size.height, 0);
// this is an old animation method, but the only one that retains compaitiblity between parameters (duration, curve) and the values contained in the userInfo-Dictionary.
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:[[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue]];
[UIView setAnimationCurve:[[userInfo objectForKey:UIKeyboardAnimationCurveUserInfoKey] intValue]];
_scrollView.contentInset = newContentInsets;
_scrollView.scrollIndicatorInsets = newContentInsets;
/*
* Depending on visual layout, _focusedControl should either be the input field (UITextField,..) or another element
* that should be visible, e.g. a purchase button below an amount text field
* it makes sense to set _focusedControl in delegates like -textFieldShouldBeginEditing: if you have multiple input fields
*/
if (_focusedControl) {
CGRect controlFrameInScrollView = [_scrollView convertRect:_focusedControl.bounds fromView:_focusedControl]; // if the control is a deep in the hierarchy below the scroll view, this will calculate the frame as if it were a direct subview
controlFrameInScrollView = CGRectInset(controlFrameInScrollView, 0, -10); // replace 10 with any nice visual offset between control and keyboard or control and top of the scroll view.
CGFloat controlVisualOffsetToTopOfScrollview = controlFrameInScrollView.origin.y - _scrollView.contentOffset.y;
CGFloat controlVisualBottom = controlVisualOffsetToTopOfScrollview + controlFrameInScrollView.size.height;
// this is the visible part of the scroll view that is not hidden by the keyboard
CGFloat scrollViewVisibleHeight = _scrollView.frame.size.height - scrollViewKeyboardIntersection.size.height;
if (controlVisualBottom > scrollViewVisibleHeight) { // check if the keyboard will hide the control in question
// scroll up until the control is in place
CGPoint newContentOffset = _scrollView.contentOffset;
newContentOffset.y += (controlVisualBottom - scrollViewVisibleHeight);
// make sure we don't set an impossible offset caused by the "nice visual offset"
// if a control is at the bottom of the scroll view, it will end up just above the keyboard to eliminate scrolling inconsistencies
newContentOffset.y = MIN(newContentOffset.y, _scrollView.contentSize.height - scrollViewVisibleHeight);
[_scrollView setContentOffset:newContentOffset animated:NO]; // animated:NO because we have created our own animation context around this code
} else if (controlFrameInScrollView.origin.y < _scrollView.contentOffset.y) {
// if the control is not fully visible, make it so (useful if the user taps on a partially visible input field
CGPoint newContentOffset = _scrollView.contentOffset;
newContentOffset.y = controlFrameInScrollView.origin.y;
[_scrollView setContentOffset:newContentOffset animated:NO]; // animated:NO because we have created our own animation context around this code
}
}
[UIView commitAnimations];
}
// Called when the UIKeyboardWillHideNotification is sent
- (void)keyboardWillHide:(NSNotification*)notification
{
// if we have no view or are not visible in any window, we don't care
if (!self.isViewLoaded || !self.view.window) {
return;
}
NSDictionary *userInfo = notification.userInfo;
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:[[userInfo valueForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue]];
[UIView setAnimationCurve:[[userInfo valueForKey:UIKeyboardAnimationCurveUserInfoKey] intValue]];
// undo all that keyboardWillShow-magic
// the scroll view will adjust its contentOffset apropriately
_scrollView.contentInset = UIEdgeInsetsZero;
_scrollView.scrollIndicatorInsets = UIEdgeInsetsZero;
[UIView commitAnimations];
}
You may check it out: https://github.com/michaeltyson/TPKeyboardAvoiding (I used that sample for my apps). It is working so well. I hope that helps you.
Actually, here's a full tutorial on using TPKeyboardAvoiding, which may help someone
(1) download the zip file from the github link. add these four files to your Xcode project:
(2) build your beautiful form in IB. add a UIScrollView. sit the form items INSIDE the scroll view. (Note - extremely useful tip regarding interface builder: https://stackoverflow.com/a/16952902/294884)
(3) click on the scroll view. then at the top right, third button, you'll see the word "UIScrollView". using copy and paste, change it to "TPKeyboardAvoidingScrollView"
(4) that's it. put the app in the app store, and bill your client.
(Also, just click on the Inspector tab of the scroll view. You may prefer to turn on or off bouncing and the scroll bars - your preference.)
Personal comment - I strongly recommend using scroll view (or collection view) for input forms, in almost all cases. do not use a table view. it's problematic for many reasons. and quite simply, it's incredibly easier to use a scroll view. just lay it out any way you want. it is 100% wysiwyg in interface builder. hope it helps
This is my code, hope it will help you. It work ok in case you have many textfield
CGPoint contentOffset;
bool isScroll;
- (void)textFieldDidBeginEditing:(UITextField *)textField {
contentOffset = self.myScroll.contentOffset;
CGPoint newOffset;
newOffset.x = contentOffset.x;
newOffset.y = contentOffset.y;
//check push return in keyboar
if(!isScroll){
//180 is height of keyboar
newOffset.y += 180;
isScroll=YES;
}
[self.myScroll setContentOffset:newOffset animated:YES];
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField{
//reset offset of content
isScroll = NO;
[self.myScroll setContentOffset:contentOffset animated:YES];
[textField endEditing:true];
return true;
}
we have a point contentOffset to save contentoffset of scrollview before keyboar show. Then we will scroll content for y about 180 (height of keyboar). when you touch return in keyboar, we will scroll content to old point(it is contentOffset). If you have many textfield, you don't touch return in keyboar but you touch another textfield, it will +180 . So we have check touch return
Use any of these,
CGPoint bottomOffset = CGPointMake(0, self.MainScrollView.contentSize.height - self.MainScrollView.bounds.size.height);
[self.MainScrollView setContentOffset:bottomOffset animated:YES];
or
[self.MainScrollView scrollRectToVisible:CGRectMake(0, self.MainScrollView.contentSize.height - self.MainScrollView.bounds.size.height-30, MainScrollView.frame.size.width, MainScrollView.frame.size.height) animated:YES];
I think it's better use keyboard notifications because you don't know if the first responder (the control with focus on) is a textField or a textView (or whatever). So juste create a category to find the first responder :
#import "UIResponder+FirstResponder.h"
static __weak id currentFirstResponder;
#implementation UIResponder (FirstResponder)
+(id)currentFirstResponder {
currentFirstResponder = nil;
[[UIApplication sharedApplication] sendAction:#selector(findFirstResponder:) to:nil from:nil forEvent:nil];
return currentFirstResponder;
}
-(void)findFirstResponder:(id)sender {
currentFirstResponder = self;
}
#end
then
-(void)keyboardWillShowNotification:(NSNotification*)aNotification{
contentScrollView.delegate=nil;
contentScrollView.scrollEnabled=NO;
contentScrollViewOriginalOffset = contentScrollView.contentOffset;
UIResponder *lc_firstResponder = [UIResponder currentFirstResponder];
if([lc_firstResponder isKindOfClass:[UIView class]]){
UIView *lc_view = (UIView *)lc_firstResponder;
CGRect lc_frame = [lc_view convertRect:lc_view.bounds toView:contentScrollView];
CGPoint lc_point = CGPointMake(0, lc_frame.origin.y-lc_frame.size.height);
[contentScrollView setContentOffset:lc_point animated:YES];
}
}
Eventually disable the scroll and set the delegate to nil then restore it to avoid some actions during the edition of the first responder. Like james_womack said, keep the original offset to restore it in a keyboardWillHideNotification method.
-(void)keyboardWillHideNotification:(NSNotification*)aNotification{
contentScrollView.delegate=self;
contentScrollView.scrollEnabled=YES;
[contentScrollView setContentOffset:contentScrollViewOriginalOffset animated:YES];
}
In Swift 1.2+ do something like this:
class YourViewController: UIViewController, UITextFieldDelegate {
override func viewDidLoad() {
super.viewDidLoad()
_yourTextField.delegate = self //make sure you have the delegate set to this view controller for each of your textFields so textFieldDidBeginEditing can be called for each one
...
}
func textFieldDidBeginEditing(textField: UITextField) {
var point = textField.convertPoint(textField.frame.origin, toView: _yourScrollView)
point.x = 0.0 //if your textField does not have an origin at 0 for x and you don't want your scrollView to shift left and right but rather just up and down
_yourScrollView.setContentOffset(point, animated: true)
}
func textFieldDidEndEditing(textField: UITextField) {
//Reset scrollview once done editing
scrollView.setContentOffset(CGPoint.zero, animated: true)
}
}