James James - 3 months ago 18
Objective-C Question

Keyboard Scroll on Active Text Field - Scrolling to Out of View?

I have an application with a view that has text fields from the top of the view to the bottom of the view. I needed it to scroll when editing the bottom fields so that the fields would be visible, but it's not seeming to work correctly.

Following the Apple docs, I placed all of that code into my program (Listings 4-1, 4-2), and added the

scrollView
and
activeField
outlets to my header file and linked them to IB.

The problem is as soon as I click into a text field, ALL of the text fields go out of view until I dismiss the keyboard. They scroll down very far (again, far enough to where none of the fields are visible).

Does anyone know what that problem could be caused by?

I'm placing the code in here from the Apple Docs so you can see exactly what code I'm using without having to click away.

//my .h
IBOutlet UIScrollView *scrollView;
IBOutlet UITextField *activeField;

//.m
// Call this method somewhere in your view controller setup code.
- (void)registerForKeyboardNotifications
{
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWasShown:)
name:UIKeyboardDidShowNotification object:nil];

[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillBeHidden:)
name:UIKeyboardWillHideNotification object:nil];

}

// Called when the UIKeyboardDidShowNotification is sent.
- (void)keyboardWasShown:(NSNotification*)aNotification
{
NSDictionary* info = [aNotification userInfo];
CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;

UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, kbSize.height, 0.0);
scrollView.contentInset = contentInsets;
scrollView.scrollIndicatorInsets = contentInsets;

// If active text field is hidden by keyboard, scroll it so it's visible
// Your application might not need or want this behavior.
CGRect aRect = self.view.frame;
aRect.size.height -= kbSize.height;
if (!CGRectContainsPoint(aRect, activeField.frame.origin) ) {
CGPoint scrollPoint = CGPointMake(0.0, activeField.frame.origin.y-kbSize.height);
[scrollView setContentOffset:scrollPoint animated:YES];
}
}

// Called when the UIKeyboardWillHideNotification is sent
- (void)keyboardWillBeHidden:(NSNotification*)aNotification
{
UIEdgeInsets contentInsets = UIEdgeInsetsZero;
scrollView.contentInset = contentInsets;
scrollView.scrollIndicatorInsets = contentInsets;
}
- (void)textFieldDidBeginEditing:(UITextField *)textField
{
activeField = textField;
}

- (void)textFieldDidEndEditing:(UITextField *)textField
{
activeField = nil;
}

Answer

UPDATE: Below answer is outdated. For now you can use "TPkeyboardavoiding" library for handle all kind of text field operation in UIScrollView, UITableView & many more. Try it and let me know if any one have a problem in integration.

Old Answer

There is no need to register for the keyboard notifications for this functionality. In order to center the active textField the screen above the keyboard, you only have to set the contentOffset of the UIscrollView two methods as shown here:

// called when textField start editting.
- (void)textFieldDidBeginEditing:(UITextField *)textField
{
    activeField = textField;
    [scrollView setContentOffset:CGPointMake(0,textField.center.y-60) animated:YES];
}



// called when click on the retun button.
- (BOOL)textFieldShouldReturn:(UITextField *)textField
{


    NSInteger nextTag = textField.tag + 1;
    // Try to find next responder
    UIResponder *nextResponder = [textField.superview viewWithTag:nextTag];

    if (nextResponder) {
        [scrollview setContentOffset:CGPointMake(0,textField.center.y-60) animated:YES];
        // Found next responder, so set it.
        [nextResponder becomeFirstResponder];
    } else {
        [scrollview setContentOffset:CGPointMake(0,0) animated:YES];
        [textField resignFirstResponder];   
        return YES;
    }

    return NO; 
}

Note: All TextField should have incremental tags Like 1,2,3 and so no. And set delegates to self.

Thanks,