Question
With the iOS SDK:
I have a UIView
with UITextField
s that bring up a keyboard. I need it to
be able to:
-
Allow scrolling of the contents of the
UIScrollView
to see the other text fields once the keyboard is brought up -
Automatically "jump" (by scrolling up) or shortening
I know that I need a UIScrollView
. I've tried changing the class of my
UIView
to a UIScrollView
, but I'm still unable to scroll the textboxes up
or down.
Do I need both a UIView
and a UIScrollView
? Does one go inside the other?
What needs to be implemented in order to automatically scroll to the active text field?
Ideally as much of the setup of the components as possible will be done in Interface Builder. I'd like to only write code for what needs it.
Note: the UIView
(or UIScrollView
) that I'm working with is brought up by
a tabbar (UITabBar
), which needs to function as normal.
I am adding the scroll bar just for when the keyboard comes up. Even though it's not needed, I feel like it provides a better interface because then the user can scroll and change textboxes, for example.
I've got it working where I change the frame size of the UIScrollView
when
the keyboard goes up and down. I'm simply using:
-(void)textFieldDidBeginEditing:(UITextField *)textField {
//Keyboard becomes visible
scrollView.frame = CGRectMake(scrollView.frame.origin.x,
scrollView.frame.origin.y,
scrollView.frame.size.width,
scrollView.frame.size.height - 215 + 50); // Resize
}
-(void)textFieldDidEndEditing:(UITextField *)textField {
// Keyboard will hide
scrollView.frame = CGRectMake(scrollView.frame.origin.x,
scrollView.frame.origin.y,
scrollView.frame.size.width,
scrollView.frame.size.height + 215 - 50); // Resize
}
However, this doesn't automatically "move up" or center the lower text fields in the visible area, which is what I would really like.
Answer
-
You will only need a
ScrollView
if the contents you have now do not fit in the iPhone screen. (If you are adding theScrollView
as the superview of the components just to make theTextField
scroll up when keyboard comes up, then it's not needed.) -
The standard way to prevent the
TextField
s from being covered by the keyboard is to move the view up/down whenever the keyboard is shown.
Here is some sample code:
#define kOFFSET_FOR_KEYBOARD 80.0
-(void)keyboardWillShow {
// Animate the current view out of the way
if (self.view.frame.origin.y >= 0)
{
[self setViewMovedUp:YES];
}
else if (self.view.frame.origin.y < 0)
{
[self setViewMovedUp:NO];
}
}
-(void)keyboardWillHide {
if (self.view.frame.origin.y >= 0)
{
[self setViewMovedUp:YES];
}
else if (self.view.frame.origin.y < 0)
{
[self setViewMovedUp:NO];
}
}
-(void)textFieldDidBeginEditing:(UITextField *)sender
{
if ([sender isEqual:mailTf])
{
//move the main view, so that the keyboard does not hide it.
if (self.view.frame.origin.y >= 0)
{
[self setViewMovedUp:YES];
}
}
}
//method to move the view up/down whenever the keyboard is shown/dismissed
-(void)setViewMovedUp:(BOOL)movedUp
{
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:0.3]; // if you want to slide up the view
CGRect rect = self.view.frame;
if (movedUp)
{
// 1. move the view's origin up so that the text field that will be hidden come above the keyboard
// 2. increase the size of the view so that the area behind the keyboard is covered up.
rect.origin.y -= kOFFSET_FOR_KEYBOARD;
rect.size.height += kOFFSET_FOR_KEYBOARD;
}
else
{
// revert back to the normal state.
rect.origin.y += kOFFSET_FOR_KEYBOARD;
rect.size.height -= kOFFSET_FOR_KEYBOARD;
}
self.view.frame = rect;
[UIView commitAnimations];
}
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
// register for keyboard notifications
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillShow)
name:UIKeyboardWillShowNotification
object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillHide)
name:UIKeyboardWillHideNotification
object:nil];
}
- (void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
// unregister for keyboard notifications while not visible.
[[NSNotificationCenter defaultCenter] removeObserver:self
name:UIKeyboardWillShowNotification
object:nil];
[[NSNotificationCenter defaultCenter] removeObserver:self
name:UIKeyboardWillHideNotification
object:nil];
}