Views positioning with dynamic resizing

Question

I'm trying to create a UITextView where the height increase dynamically. There is a UIView to group this UITextView with a UIButton.

I've added a observer to the NSnotificationCenter for the UITextViewTextDidChangeNotification notification.

According to the height of the current tapping text , I create a new CGRect:

CGRect newRect = [contentTextView.text boundingRectWithSize:CGSizeMake(222, CGFLOAT_MAX)
                                                         options:(NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading) attributes:@{NSFontAttributeName:font} context:nil];

Then, I change the size of the current UIView:

CGRect tmp = commentView.frame;
CGRect fitRectForView = CGRectMake(tmp.origin.x, tmp.origin.y - abs(newRectH - commentView.frame.size.height), tmp.size.width, newRect.size.height);
            commentView.frame = fitRectForView; 

Finally, I change the height of my UITextView:

CGRect fitRectForTextView = CGRectMake(contentTextView.frame.origin.x, contentTextView.frame.origin.y, contentTextView.frame.size.width,newRectH);
            contentTextView.frame = fitRectForTextView;

Here is the log of the origin and the size of my contentTextView variable before and after the fitting:

//Before
contentTextView origin : 0.000000 ; 0.000000
contentTextView size : 33.000000 ; 251.000000
//After
contentTextView origin : 0.000000 ; 0.000000
contentTextView size : 84.000000 ; 251.000000

With this screenshot, you can see that only my commentView's height is changing. I put a constraint on the send button to keep it on the bottom of the UIView (commentView) but it's not effective.

I can't find my mistake.

Here is my first source: create-a-multi-line-uitextfield

Answer 1

If your UITextView is on your View Controller's view and not inside a Keyboard input accessory view, then this is how I usually do it with constraints:

-(void)viewDidLoad
{
    ...

    myTextView = [[UITextView alloc] init];
    myTextView.scrollEnabled = NO;

    myTextView.translateAutoresizingMaskIntoConstraints = NO;

    // -----------------------------------------------
    // set textview delegate for delegate method
    // -----------------------------------------------
    myTextView.delegate = self;

    // -----------------------------------------------
    // put your code to setup all the constraint 
    // for your textView here
    //
    // Note: alternatively, you can set your constraints
    // using Interface Builder.
    // -----------------------------------------------


}

// -----------------------------------------------
// This is the UITextView delegate method so make
// sure your .h file has conformed to 
// UITextViewDelegate method
// -----------------------------------------------
-(BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
    ...

    // let autolayout know the textView needs to relayout
    [textView invalidateIntrinsicContentSize];

    return YES;
}

Additional info

If you want the button to appear the bottom of your view, then you need to set the button to pin to the bottom of your UIView container.

With constraints in code, this is how it's done:

id views = @{"containerView": self.containerView, @"contentTextView": self. contentTextView, @"myButton": self.myButton};

// make your container view expand to fill up your root view
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[containerView]|" options:0 metrics:nil views:views]];
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[containerView]|" options:0 metrics:nil views:views]];

// text view constraints
[self.containerView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-10-[contentTextView]-10-[myButton]-10-|" options:0 metrics:nil views:views]];
[self.containerView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-10-[contentTextView]-10-|" options:0 metrics:nil views:views]];

// button constraints

// note here, we make the button bottom edge always same as text view's bottom edge.

[self.containerView addConstraint:[NSLayoutConstraint constraintWithItem:self.myButton attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self.contentTextView attribute:NSLayoutAttributeBottom multiplier:1.0 constant:0.0]];