UIScrollView not working properly

Question

I have one view window which I created in the interface builder. I created a UIScrollView which fills the entire window and dragged some other items into it, including a UITextView. The problem I encountered was that when I click to write into the TextView the keyboard blocks the view of the TextView, hence the use of a ScrollView.

Now I've searched around quite a bit and think I know what I need to do but if I'm doing it right is another matter.

I get the bounce, that is I can drag everything that's in the ScrollView and it will bounce back. When I then press to write in the TextView the keyboard pops up, this shrinks the ScrollView to "screen size" - "keyboard size" (I know this happens as I haven't implemented the "do this once I hide the keyboard" function yet, so when I hide the keyboard the ScrollView now ends where the keyboard started). But even though the view size is now smaller than the content size it does not scroll, simply continues to bounce.

Here below you can see the code I'm using. I call the registerForKeyboardNotifications in viewDidLoad.

// 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 *)n
{
    NSLog(@"WoopWoopWoop");

    NSDictionary* userInfo = [n userInfo];

    // get the size of the keyboard
    CGSize keyboardSize = [[userInfo objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;

    // resize the noteView
    CGRect viewFrame = self.mainScrollView.frame;

    viewFrame.size.height -= (keyboardSize.height);

    mainScrollView.bounces = YES;

    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationBeginsFromCurrentState:YES];
    [UIView setAnimationDuration:0.4];
    [self.mainScrollView setFrame:viewFrame];
    [UIView commitAnimations];
}

I've tried setting the content view to some arbitrary size such as

[mainScrollView setContentSize:CGSizeMake(3200.0,2300.0)];

but that has had no effect...

Any ideas?

Answer 1

when I click to write into the TextView the keyboard blocks the view of the TextView, hence the use of a ScrollView.

First, I would suggest that this use of UIScrollViews is not necessary (if you only have a UITextView to display. Also, remember that UITextView is a subclass of UIScrollView).

You can achieve repositioning and resizing of your UITextView by configuring it as a subview of a UIView instead. Enable autoresizesSubviews on your UIView and configure both views' springs and struts via the IB Inspector. The UIView container should take all the available space.

Using the same approach as described in your question, when the UIView is resized, it should automatically adjust the UITextView's frame as well.

Now, even if you do need to have a view hierarchy with a UIScrollView at the top, I would still suggest to wrap that into a plain UIView container, and configure autoresizing as I mentioned above.

Hope that helps!

Answer 2

Hi, you don't need to make use of notifications. Just make use of the UITextFieldDelegate protocol methods. You can set the content Offset for the scrollView in those methods.

For example:

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField {
    //Check the necessary textfield and then change yValue accordingly
    [scrollView setContentOffset:CGPointMake(0,yValue) animated:YES];
    return YES;
}