Text input box like the SMS app on the iPhone

I am having a terrible time trying to get an input box like the one in the SMS app.

Can anyone offer some guidance on how to build one of these and make it look good? I need an input box that is shaped nicely like the UITextfield but will stretch vertically when typing.

I assume that I need to calculate width of the text and stretch the overlay image frame vertically when the text word wraps. The closest I have come does stretch but the cursor bounces all around when nearing the boundaries.

UPDATE:

I have worked on this everyday for a week and I have about given up on the UITextView. I can get it to stretch properly but when backspacing, the Textview height shrinks too much when going up a line. As I continue backspacing it corrects itself. For example, it displays this behavior when I am on line 4 and backspace up to line 3. Then as I continue backspacing, it corrects until I get to the end of line 2. Then it corrects itself,.... etc.

I decided to try to subclass UITextField but I can't even get it to display in 开发者_StackOverflowthe Frame size that I specify. 150,150,150,150.

Try Chat Input Sample. It has the similar look and functionality of SMS app.

Three20 project has a control that should do this for you.

From the Three20 README:

TTTextEditor is a UITextView which can grow in height automatically as you type. I use this for entering messages in Facebook Chat, and it behaves similarly to the editor in Apple's SMS app.

You get to do this yourself. Luckily, the UITextField can notify you whenever its text changes using UITextFieldTextDidChangeNotification, and luckily NSString has methods (under the UIKit Additions) that let you get the height of the string given a certain width using boundingRectWithSize:options:attributes:context:, and luckily you can resize a UITextField yourself using frame.

I know this is old but for the people that still look at this answer there is now a nice control from Slack that does that called SlackTextViewController.