iOS的scrollView setContentOffset“ Shimmy”

Question

I have a scrollView with multiple textFields, which tracks the active field and makes sure it is visible when the keyboard pops up. It all works well, but when I tab from the 3rd to 4th textField, I get a little up and down "shimmy" before the textField ends up in the right place. Any suggestions?

-(void)keyboardDidShow:(NSNotification *)notification
{    
    if (keyboardIsShown)return;

    NSDictionary* info=[notification userInfo];
    // get keyboard size
    CGSize keyboardSize=[[info objectForKey:UIKeyboardFrameBeginUserInfoKey]CGRectValue].size;
    //Set scrollview insets to make room for keyboard
    UIEdgeInsets contentInsets=UIEdgeInsetsMake(0.0, 0.0, keyboardSize.height, 0.0);
    scrollView.contentInset=contentInsets;
    scrollView.scrollIndicatorInsets=contentInsets;

    //scroll the active text field into view
    CGRect viewFrame=self.view.frame;
    viewFrame.size.height-=keyboardSize.height;
    int fieldHeight=self.currentTextField.bounds.size.height;
    CGFloat navHeight=self.navigationController.navigationBar.frame.size.height;
    CGPoint viewPoint=CGPointMake(0.0, self.currentTextField.frame.origin.y+fieldHeight);

    if (!CGRectContainsPoint(viewFrame, viewPoint)) {
        //scroll to make sure active field is showing
        CGPoint scrollPoint=CGPointMake(0.0, viewPoint.y-keyboardSize.height+navHeight);//+navHeight
        [scrollView setContentOffset:scrollPoint animated:YES];
    }
}

-(void)showActiveField
{    
    //this makes sure that activeField shows when selecting another field after initial keyboard show
    int fieldHeight=self.currentTextField.bounds.size.height;
    CGPoint viewPoint=CGPointMake(0.0, self.currentTextField.frame.origin.y+fieldHeight);
    CGRect viewFrame=self.view.frame;

    int inset=scrollView.contentInset.bottom;
    if (!CGRectContainsPoint(viewFrame, viewPoint)) {
        //scroll to make sure active field is showing
        CGPoint scrollPoint=CGPointMake(0.0, viewPoint.y-inset);
        [scrollView setContentOffset:scrollPoint animated:YES];
    }    
}

Answer 1

Where do you set keyboardIsShown ? Don't you want to do that Right after you check if it is already set?

And then: is the 4th field near the end of the scrollview and you have bounce scroll set?