Move view when jumping from text field to text field - iphone

Question

I have a form with a few text fields on a scroll view. I was trying to solve the problem of the keyboard hiding some text fields, which I partly did. At least it works well when I tap on each individual field. I used the recommended Apple approach:
I have registered for keyboard notifications in viewDidLoad:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:self.view.window];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:self.view.window];
I am tracking active text fields:
- (void)textFieldDidBeginEditing:(UITextField *)textField {
activeTextField = textField;
}
- (void)textFieldDidEndEditing:(UITextField *)textField {
activeTextField = nil;
}
I am scrolling the view up when the keyboard shows up:
- (void)keyboardWillShow:(NSNotification *)aNotification {
// Get the size of the keyboard
NSDictionary* info = [aNotification userInfo];
keyboardHeight = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size.height;
UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, keyboardHeight, 0.0);
scrollView.contentInset = contentInsets;
scrollView.scrollIndicatorInsets = contentInsets;
// If active text field is hidden by keyboard, scroll it so it's visible
CGRect aRect = self.view.frame;
aRect.size.height -= keyboardHeight + 44 + 44; // Compensates for Navbar and text field height
if (!CGRectContainsPoint(aRect, activeTextField.frame.origin) ) {
[scrollView scrollRectToVisible:activeTextField.frame animated:YES];
}
}
I then scroll the view back to default when the keyboard is hidden (I won't paste the code simply because it works fine).
However, out of my 5 text fields, the first 4 have a Next button on the keyboard (instead or Return) while the last field has Done. The idea is that I want the user to jump from one text field to another (in one direction is enough in my case). So, I've implemented a UITextField delegate method to handle that as well:
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
if (textField == firstNameTextField) {
[lastNameTextField becomeFirstResponder];
} else if (textField == lastNameTextField) {
[countryTextField becomeFirstResponder];
} else if (textField == cityTextField) {
[zipCodeTextField becomeFirstResponder];
} else if (textField == zipCodeTextField) {
[zipCodeTextField resignFirstResponder];
}
return NO;
}
The middle text field above is skipped, because for that text field I'm using a different input type (a custom view with a UIPickerView and a bar on top with Next button) - the missing code is in this method:
- (IBAction)goToNextTextField:(id)sender {
[cityTextField becomeFirstResponder];
}
OK, as I've mentioned, view adjustment works well when tapping individual text fields (and then dismissing the keyboard), even though keyboard sizes (standard iOS vs my custom view) are different heights. I can also successfully go through all text fields tapping on Next buttons.
Here are my issues though:
When tapping on Next, if the keyboard is not changing (say, from field 4 to 5 that both use standard keyboard), my keyboardWillShow: method is not called, NSLog debugger shows keyboardHeight as 0, and yet the view moves up unpredictably.
Also, when navigating to and from field 3 (the one that uses custom input view), keyboardHeight is thus not recalculated. I have tried registering to UIKeyboardDidChangeFrameNotification and UIKeyboardWillChangeFrameNotification (pointing to keyboardWillShow: method), but without much success. It is worth noting that I do see in console that keyboardHeight is changing, but it's usually lagging one step, i.e. keyboardHeight is updated when I leave the field, not when it becomeFirstResponder.
Perhaps a pair of experienced eyes will spot my mistake, for I have been destroying my pair of eyes searching for the solution for the last 2 days..
Thanks!

Answer 1

You can use UITextField delegates . Whenever user start editing in any textfield its delegate is called you can change scrollview offset using
- (void)scrollViewToCenterOfScreen:(UIView *)theView
{
CGFloat viewCenterY = theView.center.y;
CGRect applicationFrame = [[UIScreen mainScreen] applicationFrame];
CGFloat availableHeight = applicationFrame.size.height - 200; // Remove area covered by keyboard
CGFloat y = viewCenterY - availableHeight / 2.0;
if (y < 0)
{
y = 0;
}
[scrollView setContentOffset:CGPointMake(0, y+20) animated:YES];
}
So in TextField delegate you can set
- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField
{
if([textField isEqual:textfield1])
{
[self scrollViewToCenterOfScreen:textfield1];
}
else if([textField isEqual:textfield2])
{
[self scrollViewToCenterOfScreen:textfield2];
}
return YES;
}
and when user press done or return button you can change offset to (0,0)
[scrollView setContentOffset:CGPointMake(0, 0) animated:YES];
Hope this works for you.

Answer 2

https://github.com/simonbs/BSKeyboardControls
this control can show a toolbar above the keyboard when editing a textfield like this
==========================================
-(void)textFieldDidBeginEditing:(UITextField *)textField {
if (textField == firstNameTextField) {
//move to firstNameTextField
} else if (textField == lastNameTextField) {
//move to lastNameTextField
} else if (textField == cityTextField) {
//move to cityTextField
} else if (textField == zipCodeTextField) {
//move to zipCodeTextField
}
return NO;
}

Answer 3

I have in the end implemented a solution that works well for me. It's a mixture of Apple recommended approach, a couple of solutions found on these forums as well as my own.
First of all, register as UITextFieldDelegate on view controller .h file.
Then in viewDidLoad register for keyboard notifications:
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(keyboardWillShow:)
name:UIKeyboardWillShowNotification
object:self.view.window];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(keyboardWillHide:)
name:UIKeyboardWillHideNotification
object:self.view.window];
Don't forget to unregister from them (removeObserver:) in viewDidUnload method as well.
Let your application know which text field is currently active:
- (void)textFieldDidBeginEditing:(UITextField *)textField {
activeTextField = textField;
}
- (void)textFieldDidEndEditing:(UITextField *)textField {
activeTextField = nil;
}
When your application receives a notification that keyboard will show, it calls this method:
- (void)keyboardWillShow:(NSNotification *)aNotification {
keyboardHeight = [[[aNotification userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size.height;
[scrollView setFrame:CGRectMake(scrollView.frame.origin.x,
scrollView.frame.origin.y,
scrollView.frame.size.width,
scrollView.frame.size.height - keyboardHeight)];
[self moveViewWithKeyboard];
}
All I'm doing here is decreasing the size of my scrollView frame by the size of the keyboard. After that I call my moveViewWithKeyboard: method that will make active view visible.
Interestingly enough, to solve the problem of correct keyboard height being detected one step too late (read my original question above), I had to change the argument UIKeyboardFrameBeginUserInfoKey in keyboard height detection line with UIKeyboardFrameEndUserInfoKey argument. Having done so, keyboard (or custom view) is detected when moving to the relevant field, not when moving away from it.
Of course, I have to restore original view frame when the keyboard hides (and note that I'm still calling the moveViewWithKeyboard: method with nil as an argument):
- (void)keyboardWillHide:(NSNotification *)aNotification {
[scrollView setFrame:CGRectMake(scrollView.frame.origin.x,
scrollView.frame.origin.y,
scrollView.frame.size.width,
scrollView.frame.size.height + keyboardHeight)];
[self moveViewWithKeyboard];
}
I also added calls to move view when keyboard hide/show is not triggered. This happens when I jump from text field to text field that have system keyboard as input, so it is neither hidden nor shown again (and no notifications are issued to trigger delegate methods).
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
if (textField == firstNameTextField) {
[lastNameTextField becomeFirstResponder];
} else if (textField == lastNameTextField) {
[countryTextField becomeFirstResponder];
} else if (textField == cityTextField) {
[zipCodeTextField becomeFirstResponder];
} else if (textField == zipCodeTextField) {
[zipCodeTextField resignFirstResponder];
}
[self moveViewWithKeyboard:nil];
return NO;
}
And finally my method to move view:
- (void)moveViewWithKeyboard {
if (activeTextField) {
[scrollView scrollRectToVisible:activeTextField.frame animated:YES];
} else {
[scrollView scrollRectToVisible:CGRectMake(0, 0, 1, 1) animated:YES];
}
}
Note that when no text field is passed as an argument (i.e. no text field is active), view is scrolled to its original position.
Hope this helps someone.