Scroll up view when keyboard appears

Hi,

Here I am about to help you to tackle the textfield or textview invisibility problem when keyboard appears on the screen.There are 2 delegate methods related to UITextfield and UITextView.You just have to move the current view up slightly to make the controls visible.

Here are the 2 delegates of UITextField.

1. Just declare  
   
          CGFloat animatedDistance;
     in viewController.h file.

2. Add these Constants as well,

          static const CGFloat KEYBOARD_ANIMATION_DURATION = 0.3;

          static const CGFloat MINIMUM_SCROLL_FRACTION = 0.2;

          static const CGFloat MAXIMUM_SCROLL_FRACTION = 0.8;

          static const CGFloat PORTRAIT_KEYBOARD_HEIGHT = 240;

          static const CGFloat LANDSCAPE_KEYBOARD_HEIGHT = 140;

3. Finally,add the UITextField delegates in your viewController.m as below,

    - (void)textFieldDidBeginEditing:(UITextField *)textField

    {    

         CGRect textFieldRect =

         [self.view.window convertRect:textField.bounds fromView:textField];

         CGRect viewRect =

         [self.view.window convertRect:self.view.bounds fromView:self.view];

         CGFloat midline = textFieldRect.origin.y + 0.5 * textFieldRect.size.height;

         CGFloat numerator =

            midline - viewRect.origin.y

           - MINIMUM_SCROLL_FRACTION * viewRect.size.height;

        CGFloat denominator =

              (MAXIMUM_SCROLL_FRACTION - MINIMUM_SCROLL_FRACTION)

                 * viewRect.size.height;

        CGFloat heightFraction = numerator / denominator;

       if (heightFraction < 0.0){

             heightFraction = 0.0;

        }else if (heightFraction > 1.0) {

                  heightFraction = 2.0;

        }

     
        UIInterfaceOrientation orientation =

               [[UIApplication sharedApplication] statusBarOrientation];

 
        if (orientation == UIInterfaceOrientationPortrait ||

                        orientation == UIInterfaceOrientationPortraitUpsideDown)

        {

                animatedDistance = floor(PORTRAIT_KEYBOARD_HEIGHT * heightFraction);

         }

        else

        {

              animatedDistance = floor(LANDSCAPE_KEYBOARD_HEIGHT * heightFraction);

        }

        CGRect viewFrame = self.view.frame;

        viewFrame.origin.y -= animatedDistance;

    

        [UIView beginAnimations:nil context:NULL];

        [UIView setAnimationBeginsFromCurrentState:YES];

        [UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION];

    

        [self.view setFrame:viewFrame];

    

        [UIView commitAnimations];

    }

    - (void)textFieldDidEndEditing:(UITextField *)textField

    {

    

        if(self.view.frame.origin.y == 0)

              return;

    

        if (animatedDistance == 0.0)

             return;

    

         CGRect viewFrame = self.view.frame;

         viewFrame.origin.y += animatedDistance;

    

         [UIView beginAnimations:nil context:NULL];

         [UIView setAnimationBeginsFromCurrentState:YES];

         [UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION];

    

         [self.view setFrame:viewFrame];

    

         [UIView commitAnimations];

    

         animatedDistance = 0.0;

     }

You are done !

For UITextView you have to replace above delegate methods with

- (void)textViewDidBeginEditing:(UITextView *)textVield and
- (void)textViewDidEndEditing:(UITextView *)textView

respectively.

Feel free to comment. Thanks :)