Making a UITableView scroll when text field is sel

Question

After a lot of trial and error, I'm giving up and asking the question. I've seen a lot of people with similar problems but can't get all the answers to work right.

I have a UITableView which is composed of custom cells. The cells are made of 5 text fields next to each other (sort of like a grid).

When I try to scroll and edit the cells at the bottom of the UITableView, I can't manage to get my cells properly positioned above the keyboard.

I have seen many answers talking about changing view sizes,etc... but none of them has worked nicely so far.

Could anybody clarify the "right" way to do this with a concrete code example?

Answer 1

Keyboard notifications work, but Apple's sample code for that assumes that the scroll view is the root view of the window. This is usually not the case. You have to compensate for tab bars, etc., to get the right offset.

It is easier than it sounds. Here is the code I use in a UITableViewController. It has two instance variables, hiddenRect and keyboardShown.

// Called when the UIKeyboardDidShowNotification is sent.
- (void)keyboardWasShown:(NSNotification*)aNotification {
    if (keyboardShown)
        return;

    NSDictionary* info = [aNotification userInfo];

    // Get the frame of the keyboard.
    NSValue *centerValue = [info objectForKey:UIKeyboardCenterEndUserInfoKey];
    NSValue *boundsValue = [info objectForKey:UIKeyboardBoundsUserInfoKey];
    CGPoint keyboardCenter = [centerValue CGPointValue];
    CGRect keyboardBounds = [boundsValue CGRectValue];
    CGPoint keyboardOrigin = CGPointMake(keyboardCenter.x - keyboardBounds.size.width / 2.0,
                                         keyboardCenter.y - keyboardBounds.size.height / 2.0);
    CGRect keyboardScreenFrame = { keyboardOrigin, keyboardBounds.size };


    // Resize the scroll view.
    UIScrollView *scrollView = (UIScrollView *) self.tableView;
    CGRect viewFrame = scrollView.frame;
    CGRect keyboardFrame = [scrollView.superview convertRect:keyboardScreenFrame fromView:nil];
    hiddenRect = CGRectIntersection(viewFrame, keyboardFrame);

    CGRect remainder, slice;
    CGRectDivide(viewFrame, &slice, &remainder, CGRectGetHeight(hiddenRect), CGRectMaxYEdge);
    scrollView.frame = remainder;

    // Scroll the active text field into view.
    CGRect textFieldRect = [/* selected cell */ frame];
    [scrollView scrollRectToVisible:textFieldRect animated:YES];

    keyboardShown = YES;
}


// Called when the UIKeyboardDidHideNotification is sent
- (void)keyboardWasHidden:(NSNotification*)aNotification
{
    // Reset the height of the scroll view to its original value
    UIScrollView *scrollView = (UIScrollView *) self.tableView;
    CGRect viewFrame = [scrollView frame];
    scrollView.frame = CGRectUnion(viewFrame, hiddenRect);

    keyboardShown = NO;
}

Answer 2

Very interesting discussion thread, i also faced the same problem may be worse one because

1. I was using a custom cell and the textfield was inside that.
2. I had to use UIViewController to meet my requirements so cant take advantage of UITableViewController.
3. I had filter/ sort criterias in my table cell, ie ur cells keeps on changing and keeping track of the indexpath and all will not help.

So read the threads here and implemented my version, which helped me in pushing up my contents in iPad in landscape mode. Here is code ( this is not fool proof and all, but it fixed my issue) First u need to have a delegate in your custom cell class, which on editing begins, sends the textfield to ur viewcontroller and set the activefield = theTextField there

// IMPLEMENTED TO HANDLE LANDSCAPE MODE ONLY

- (void)keyboardWasShown:(NSNotification*)aNotification
{
    NSDictionary* info = [aNotification userInfo];
    CGSize kbValue = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
    CGRect aRect = myTable.frame;

    CGSize kbSize = CGSizeMake(kbValue.height, kbValue.width);

    aRect.size.height -= kbSize.height+50;
// This will the exact rect in which your textfield is present
        CGRect rect =  [myTable convertRect:activeField.bounds fromView:activeField];
// Scroll up only if required
    if (!CGRectContainsPoint(aRect, rect.origin) ) {


            [myTable setContentOffset:CGPointMake(0.0, rect.origin.y) animated:YES];

    }


}

// Called when the UIKeyboardWillHideNotification is sent

- (void)keyboardWillHide:(NSNotification*)aNotification
{
    UIEdgeInsets contentInsets = UIEdgeInsetsZero;
    myTable.contentInset = contentInsets;
    myTable.scrollIndicatorInsets = contentInsets;
    NSDictionary* info = [aNotification userInfo];
    CGSize kbValue = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
    CGSize kbSize = CGSizeMake(kbValue.height, kbValue.width);
    CGRect bkgndRect = activeField.superview.frame;
    bkgndRect.size.height += kbSize.height;
    [activeField.superview setFrame:bkgndRect];
    [myTable setContentOffset:CGPointMake(0.0, 10.0) animated:YES];
}

-anoop4real

Answer 3

An example in Swift, using the exact point of the text field from Get indexPath of UITextField in UITableViewCell with Swift:

func textFieldDidBeginEditing(textField: UITextField) {
    let pointInTable = textField.convertPoint(textField.bounds.origin, toView: self.accountsTableView)
    let textFieldIndexPath = self.accountsTableView.indexPathForRowAtPoint(pointInTable)
    accountsTableView.scrollToRowAtIndexPath(textFieldIndexPath!, atScrollPosition: .Top, animated: true)
}

Answer 4

I had the same problem but noticed that it appears only in one view. So I began to look for the differences in the controllers.

I found out that the scrolling behavior is set in - (void)viewWillAppear:(BOOL)animated of the super instance.

So be sure to implement like this:

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    // your code
}

And it doesn't matter if you use UIViewController or UITableViewController; checked it by putting a UITableView as a subview of self.view in the UIViewController. It was the same behavior. The view didn't allow to scroll if the call [super viewWillAppear:animated]; was missing.

Answer 5

Another easy method (only works with one section)

//cellForRowAtIndexPath
UItextField *tf;
[cell addSubview:tf];
tf.tag = indexPath.row;
tf.delegate = self;

//textFieldDidBeginEditing:(UITextField *)text
[[self.tableView scrollToRowsAtIndexPath:[NSIndexPath indexPathForRow:text.tag in section:SECTIONINTEGER] animated:YES];

Answer 6

Use UITextField's delegate method :

Swift

func textFieldShouldBeginEditing(textField: UITextField) -> bool {
  let txtFieldPosition = textField.convertPoint(textField.bounds.origin, toView: yourTableViewHere)
  let indexPath = yourTablViewHere.indexPathForRowAtPoint(txtFieldPosition)
  if indexPath != nil {
     yourTablViewHere.scrollToRowAtIndexPath(indexPath!, atScrollPosition: .Top, animated: true)
  }
  return true
}

Objective-C

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField
{
  CGPoint txtFieldPosition = [textField convertPoint:CGPointZero toView: yourTablViewHere];
  NSLog(@"Begin txtFieldPosition : %@",NSStringFromCGPoint(txtFieldPosition));
  NSIndexPath *indexPath = [yourTablViewHere indexPathForRowAtPoint:txtFieldPosition];

  if (indexPath != nil) {
     [yourTablViewHere scrollToRowAtIndexPath:indexPath atScrollPosition:UITableViewScrollPositionMiddle animated:YES];
  }
  return YES;
}