从预测键盘切换为简单键盘（iOS 8）时，UIScrollView（包含多个UITextField）正在上下弹跳

Question

I am trying to handle the keyboard appearance on the screen and moving the UIScrollView ( tfScroll ) to make my all UITextFields ( tf1, tf2, tf3, tf4, tf5, tf6, tf7 ) visible above the keyboard.

• I have added the Keyboard notifications ( UIKeyboardWillShowNotification , UIKeyboardWillHideNotification ) in viewWillAppear method.
• I made 'correction' option of textfields tf1, tf3, tf5, tf7 YES , and rest of the textfields to NO ie keyboards with 'YES' to correction option will have predictive bar and others with 'NO' to correction option will not have predictive bar .
• ScrollView is scrolling very fine and all textfields are visible except one issue that, when predictive bar of the keyboard appears or vanish , the scrollview bounces to the top and then comes to it's right position, which gives weird look.
• But if I switch off/on the predictive bar of keyboard for all the textfields , then scrollview scrolls smoothly.
• Please suggest some way to handle the rough scrolling in case of switching from simple keyboard to perdictive_bar keyboard .
• Here is the code that I have implemented to do the above process:

pragma mark - Keyboard Notification

- (void)keyboardWillShow: (NSNotification *) noti
{
    NSDictionary *info = [noti userInfo];


    float kbOffset = [[[noti userInfo] valueForKey:@"UIKeyboardFrameEndUserInfoKey"] CGRectValue].origin.y;


    CGSize keyboardSize = [info[UIKeyboardFrameEndUserInfoKey]CGRectValue].size;


    [UIView beginAnimations:nil context:NULL];

    [UIView setAnimationDuration:[info[UIKeyboardAnimationDurationUserInfoKey] doubleValue]];

    [UIView setAnimationCurve:[info[UIKeyboardAnimationCurveUserInfoKey] integerValue]];

    [UIView setAnimationBeginsFromCurrentState:YES];



    UIEdgeInsets insets = UIEdgeInsetsMake(tfScroll.contentInset.top, 0, keyboardSize.height+10.0, 0);


    tfScroll.contentInset = insets;

    tfScroll.scrollIndicatorInsets = insets;


    float tfOffset ;

    if (tf1.isEditing)
    {
        tfOffset = tfScroll.frame.origin.y + tf1.frame.origin.y + tf1.frame.size.height ;
    }

    else if (tf2.isEditing)
    {
        tfOffset = tfScroll.frame.origin.y +  tf2.frame.origin.y + tf2.frame.size.height ;
    }

    else if (tf3.isEditing)
    {
        tfOffset = tfScroll.frame.origin.y +  tf3.frame.origin.y + tf3.frame.size.height ;
    }

    else if (tf4.isEditing)
    {
        tfOffset = tfScroll.frame.origin.y + tf4.frame.origin.y + tf4.frame.size.height ;
    }

    else if (tf5.isEditing)
    {
        tfOffset = tfScroll.frame.origin.y + tf5.frame.origin.y + tf5.frame.size.height ;
    }

    else if (tf6.isEditing)
    {
        tfOffset = tfScroll.frame.origin.y + tf6.frame.origin.y + tf6.frame.size.height ;
    }

    else if (tf7.isEditing)
    {
        tfOffset = tfScroll.frame.origin.y + tf7.frame.origin.y + tf7.frame.size.height ;
    }


    if ((kbOffset - tfOffset) < 0)
    {
        CGFloat y = (kbOffset - tfOffset);

        tfScroll.contentOffset = CGPointMake(tfScroll.frame.origin.x, y);
    }


    [UIView commitAnimations];
}


- (void)keyboardWillHide: (NSNotification *) noti
{
    UIEdgeInsets insets = UIEdgeInsetsMake(tfScroll.contentInset.top, 0, 0, 0);


    tfScroll.contentInset = insets;

    tfScroll.scrollIndicatorInsets = insets;

    tfScroll.contentOffset = CGPointMake(tfScroll.frame.origin.x, 0);
}

Answer 1

I found the error in my code. It was silly mistake though. When I was changing the 'content offset' of UIScrollView to pull the hidden UITextFields above the keyboard in 'keyboardWillShow' method, I was assigning negative 'y-axis' to content offset, which causes bounces in my scrollview (as difference of (kbOffset - tfOffset) is negative).

So I made a little change in above code, provide +ve y-axis displacement to Scrollview, and starts running fine.

 if ((kbOffset - tfOffset) < 0)
{
    CGFloat y = (tfOffset - kbOffset);

    tfScroll.contentOffset = CGPointMake(tfScroll.frame.origin.x, y);
}