为什么视图在键盘存在时为文本视图而不是文本字段时向上滚动？

Question

I have a textfield and a textview in a scroll view. When I begin to edit the textview the view scrolls up appropriately so the keyboard does not hide the text. The textfield, however, does not scroll up but is hidden by the keyboard. I have set the delegates of the textfields and textviews to the view controllers. The code I have so far is below. Thanks for the help in advance.

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

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

- (void)registerForKeyboardNotifications
{
[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(keyboardWasShown:)
                                             name:UIKeyboardDidShowNotification object:nil];

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

}


- (void)keyboardWasShown:(NSNotification*)aNotification
{
NSDictionary* info = [aNotification userInfo];
CGRect kbRect = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue];
kbRect = [self.view convertRect:kbRect toView:nil];

CGSize kbSize = kbRect.size;

UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, kbSize.height, 0.0);
pageScrollView.contentInset = contentInsets;
pageScrollView.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);
    [pageScrollView setContentOffset:scrollPoint animated:YES];
}
}


- (void)keyboardWillBeHidden:(NSNotification*)aNotification
{
UIEdgeInsets contentInsets = UIEdgeInsetsZero;
pageScrollView.contentInset = contentInsets;
pageScrollView.scrollIndicatorInsets = contentInsets;
}

Answer 1

michael tyson created TPKeyboardAvoiding which is very easy to use you can get it from github. https://github.com/michaeltyson/TPKeyboardAvoiding

Answer 2

I do not know why it works for your textview, but for a scrollview with textfields I am doing this manually via

// Called when the UIKeyboardDidShowNotification is sent.
- (void)keyboardWillBeShown:(NSNotification*)aNotification
{
    if(keyboardShown) return;

    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.5];
    [UIView setAnimationDelegate:self];

    NSDictionary* info = [aNotification userInfo];

    // Get the size of the keyboard.
    NSValue* keyboardFrameValue     = [info objectForKey:UIKeyboardFrameEndUserInfoKey];
    CGRect keyboardRectWrtScreen    = [keyboardFrameValue CGRectValue];
    CGRect keyboardRectWrtView      = [scrollView convertRect:[[scrollView window] convertRect:keyboardRectWrtScreen fromWindow:nil] fromView: nil];

    float keyboardHeight = keyboardRectWrtView.size.height;

    scrollView.frame = CGRectMake(scrollView.frame.origin.x, scrollView.frame.origin.y, scrollView.frame.size.width,scrollView.frame.size.height-keyboardHeight);

    if(activeTextField) {
        CGRect rect = [contentView convertRect:[activeTextField bounds] fromView:activeTextField];
        rect.origin.y -= 25;
        rect.size.height += 50;
        [scrollView scrollRectToVisible:rect animated:YES];
    }

    [UIView commitAnimations];

    keyboardShown = YES;
}

as you see, I am manually moving the scroll view to the visible part, then ensuring that the text field is in the center of the scroll view.