changing the frame of UITextView as I am typing - iphone

Question

I can use the code below to set the size of the textView frame, to approximately match the textView's content (the typed text) when I press a button or whatnot. How would I call this whenever a new character is typed, so that the frame would grow or shrink interactively?
- (IBAction)doneEditingText:(id)sender {
[myTextView resignFirstResponder];
[myTextView setFrame:CGRectMake(myTextView.frame.origin.x, myTextView.frame.origin.y, myTextView.contentSize.width, myTextView.contentSize.height)];
}
Thanks for reading

Answer 1

EDIT :
Implement UITextView delegate in .h file this:
#interface ViewController : UIViewController<UITextViewDelegate>
If yourTextView added from xib then bind delegate with fileowner otherwise in ViewDidLoad add this line:
yourTextView.delegate = self;
Use textView's delegate for your requirement:
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
CGSize maximumSize = CGSizeMake(280,999); //specify width of textView and maximum height for text to fit in width of textView
CGSize txtSize = [textView.text sizeWithFont:[UIFont fontWithName:#"Arial" size:16] constrainedToSize:maximumSize lineBreakMode:UILineBreakModeCharacterWrap]; //calulate size of text by specifying font here
//Add UIViewAnimation here if needed
[textView setFrame:CGRectMake(textView.frame.origin.x,textView.frame.origin.y,txtSize.width+10,txtSize.height+10)]; // change accordingly
return YES;
}

Answer 2

You can use something like this repo on GIT which has the almost same functionality that you want-
https://github.com/HansPinckaers/GrowingTextView
it's similar like message app in iPhone.

Answer 3

I just got done implementing this. The problem with the current (as of posting this answer) accepted answer is that the delegate method:
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
exposes the textView before the change the user has typed/inserted/deleted is commited. therefore, the resizing you would be achieving would be one character late. UITextView does inherit from a UIScrollView so the text wouldn't clip off of screen but it could lead to some awkward behavior.
My Solution is to use two delegate methods to achieve the resizing effect correctly.
Expanding the UITextView before the character the user typed hits the screen:
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
NSMutableString *tempString = [NSMutableString stringWithString:textView.text];
[tempString replaceCharactersInRange:range withString:text];
//If we are adding to the length of the string (We might need to expand)
if([tempString length]>textView.text.length)
{
//Create a temporaryTextView which has all of the characteristics of your original textView
UITextView *tempTextView = [[UITextView alloc] initWithFrame:CGRectZero];
tempTextView.font = _inputFont;
tempTextView.contentInset = textView.contentInset;
[tempTextView setText:tempString];
//Change this to respect whatever width constraint you are trying to achieve.
CGSize theSize = [tempTextView sizeThatFits:CGSizeMake(192, CGFLOAT_MAX)];
if(theSize.height!=textView.frame.size.height)
{
textView.frame = CGRectMake(115, 310, 192,theSize.height);
return YES;
}
else
{
return YES;
}
}
else
{
return YES;
}
}
And Shrinking after the user has deleted/shrunk the amount of text in the UITextView the character
-(void)textViewDidChange:(UITextView *)textView
{
//We enter this method AFTER the edit has been drawn to the screen, therefore check to see if we should shrink.
if([textView sizeThatFits:CGSizeMake(192, CGFLOAT_MAX)].height!=textView.frame.size.height)
{
//change this to reflect the constraints of your UITextView
textView.frame = CGRectMake(115, 310, 192,[textView sizeThatFits:CGSizeMake(192, CGFLOAT_MAX)].height);
}
}