UITextView Snippet

!!!!!! 
On every user input the methods "textViewDidChange", "resizeTextViewHeight" and "textView:shouldChangeTextInRange" will be called
!!!!!!

hide keyboard when pressing return button
-----------------------------------------

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text {

    if([text isEqualToString:@"\n"]) {
        [textView resignFirstResponder];
        return NO;
    }

    return YES;
}

method that will be called for each keyboard press
--------------------------------------------------

- (void)textViewDidChange:(UITextView *)textView;

center text vertically inside a textview
----------------------------------------

    [self.textViewDescription addObserver:self
                               forKeyPath:@"contentSize"
                                  options:(NSKeyValueObservingOptionNew)
                                  context:NULL];
    
    [super viewDidLoad];

-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
    UITextView *tv = object;
    CGFloat topCorrect = ([tv bounds].size.height - [tv contentSize].height * [tv zoomScale])/2.0;
    topCorrect = ( topCorrect < 0.0 ? 0.0 : topCorrect );
    tv.contentOffset = (CGPoint){.x = 0, .y = -topCorrect};
}