How to get offset from start of line of UITextRange.start

Question

I have an UITextView which can have multiple lines. All I'm interested in is the position of the cursor on a certain line (where it doesn't matter whether first, second, third line etc.).

I've been logging UITextRange.start which gives me exactly what I need, namely the offset property:

cp <UITextPositionImpl: 0x6e93260> <<WebVisiblePosition: 0x6e92d00>(offset=5, context=([d|], [u+0064|u+0000])>

My question is how I get the offset=5 into a simply integer?

Here is my code:

UITextRange *caretPositionRange = textView.selectedTextRange; NSLog(@"cp %@", caretPositionRange.start);

All I need would be something like int cp = caretPositionRange.start.offset which doesn't work.

edit:

to clarify, I'm particularly interested in the cursor position of each line, not the entire TextView. So this won't really work:

UITextRange *caretPositionRange = tv.selectedTextRange; int caretPosition = [tv offsetFromPosition:tv.beginningOfDocument toPosition:caretPositionRange.start];

as this would give me a different position for each line.

edit 2:

the answer below given by Jesse works really well. First time around, I got an EXC_BAD_EXCESS as I didn't check if startOfLine = nil, so keep in mind checking if it's not nil.

Jesse Rusak · Accepted Answer · 2012-06-10 19:54:28Z

3

You'll need to ask the UITextView via its UITextInput methods. Something like this:

UITextPosition *pos = caretPositionRange.start; id<UITextInputTokenizer> tokenizer = [textView tokenizer]; UITextPosition *startOfLine = [tokenizer positionFromPosition:pos toBoundary:UITextGranularityLine inDirection:UITextStorageDirectionBackward]; if (startOfLine != nil) { // based on some experiments, startOfLine may be nil for, eg, empty text views // the next line crashes if you pass nil, so we check first NSUInteger offset = [textView offsetFromPosition:startOfLine toPosition:pos]; }

edited Jun 10, 2012 at 19:54

answered Jun 10, 2012 at 19:17

Jesse Rusak

57.3k12 gold badges103 silver badges102 bronze badges

Sign up to request clarification or add additional context in comments.

9 Comments

n.evermind Over a year ago

This won't work as I'm not interested in the position from the beginningOfDocument, but rather the beginning of the line. Offset will always give me the exact value. If I do what you suggest, I will get increasing values, e.g. I won't always get offset=5 if the cursor is on the fifth position from the beginning of a line.

Jesse Rusak Over a year ago

Oh, wow. I completely mis-read your question, sorry. One sec.

Jesse Rusak Over a year ago

OK, that should do it now. You might want to use UITextLayoutDirectionLeft instead depending on how it should handle right-to-left text.

Jesse Rusak Over a year ago

Sorry; I fixed a small bug. Try now.

Jesse Rusak Over a year ago

let us continue this discussion in chat

|

Collectives™ on Stack Overflow

How to get offset from start of line of UITextRange.start

1 Answer 1

9 Comments

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

9 Comments

Related