Question

For an iOS application I am writing I am using an UITextView, where the user can insert a limited text.

To the textview there are 2 restrictions:

1. Lines can be no longer than 30 characters
2. There can be only 20 lines of text in the UITextView.

So in short, the maximum is 20 lines of 30 characters.

When a user is typing some text in the UITextView and the current sentence is 30 characters, I want it to automatically insert a new line \n (before the last word on that line) and force the last word and cursor to the line below.

When a user has 20 lines with 30 characters (or even simpler said: 20 lines, with 30 characters on the last line) I want the input to be blocked.

Now, most of this is fairly ‘simple’ but the code I have does not account for border cases, like inserting text in earlier lines.

I looked around the documentation from Apple, but I can not find a way to actually force this kind of Word-wrapping on a UITextView.

My try is to handle all this in the shouldChangeTextInRange delegate method (made the code a little more verbose, so it’s a bit easier to read).

#define MAX_LENGTH_LINE 30
#define MAX_LENGTH_ROWS 20

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
    // Check for backspaces, they should always be allowed?
    if ([text length] == 0 && ![text isEqualToString:@"\n"])
        return YES;

    NSArray* lines = [textView.text componentsSeparatedByString:@"\n"];

    // Check if there are a maximum of lines and the last line is already maxed out
    NSString* lastLine = [lines objectAtIndex:[lines count] - 1];

    if (([lines count] == MAX_LENGTH_ROWS) &&
        (lastLine != nil) &&
        ([lastLine length] > MAX_LENGTH_LINE) &&
        ([text length] > 0))
        return NO;


    if ((lastLine != nil) &&
        ([lastLine length] > MAX_LENGTH_LINE))
    {
        NSRange range = [textView.text rangeOfString:@" " options:NSBackwardsSearch];
        NSRange breakRange = [textView.text rangeOfString:@"\n" options:NSBackwardsSearch];

        if (breakRange.location == NSNotFound)
            breakRange = NSMakeRange(0, 1);

        if (range.location == NSNotFound) {
            range = NSMakeRange(0, 1);
        }

        if (range.location > breakRange.location)
        {
            textView.text = [textView.text stringByReplacingCharactersInRange:NSMakeRange(range.location, 1) withString:@"\n"];
        }
        else
        {
            textView.text = [textView.text stringByAppendingString:@"\n"];
        }
    }

    if ([text isEqualToString:@"\n"])
    {
        if ([lines count] == MAX_LENGTH_ROWS)
            return NO;
        else {
            return YES;
        }
        NSRange range = NSMakeRange(textView.text.length - 1, 1);
        [textView scrollRangeToVisible:range];
    }

    return YES;
}

In the meanwhile I have been at this for a while and I lost it at the moment. Anyone who can give some pointers to just limit the UITextView to the 20 lines / 30 characters limitation I want?

Answer 1

After a bit of fiddling around, created a control which contains a UITextView as a subview.

I let this control handle the text wrapping and forward the delegate methods to the view registered as a delegate.

It might help others, so I am posting a link to BitBucket here.

PS. It’s still very verbose, but that is to show how I solved this for my case.

https://bitbucket.org/depl0y/sbframework/src/master/SBFramework/Views/SBTextView?at=master