How to create auto resizing input bar

I want to impleme开发者_运维问答nt a in-app chat view like the following pic. http://img408.imageshack.us/img408/4057/img0139.png

How can I implement the input bar? As I cannot found any resourece on internet.

Thanks.

Best,

Dante

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Don't count newline chars, since you will miss lines added by long sentences, but use NSString's sizeWithFont methods. See Documentation for NSString sizeWithFont:forWidth:lineBreakMode: method (in the iPhone SDK)?

Then resize all elements appropriately (no, this will not happen by itself, you have to do it).

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Use a UITextView, check for new line character in textViewDidBeginEditing and increase the height of the text view (and the background view if you have one).