UITextPosition to Int

问题

I have a UISearchBar on which I am trying to set a cursor position. I am using UITectField delegates as I couldn't find anything direct for UISearchBar. Below is the code I am using:

  UITextField *textField = [searchBar valueForKey: @"_searchField"];
  // Get current selected range , this example assumes is an insertion point or empty selection
  UITextRange *selectedRange = [textField selectedTextRange];
  // Construct a new range using the object that adopts the UITextInput, our textfield
  UITextRange *newRange = [textField textRangeFromPosition:selectedRange.start toPosition:selectedRange.end];

Question is in the 'newRange' object for 'toPosition' I want to have something like selectedRange.end-1; as I want the cursor to be on second last position.

How do I set the cursor to second last position?

回答1:

the clue is to make a position and then a range with no length and then select it

e.g.

- (IBAction)select:(id)sender {
    //get position: go from end 1 to the left
    UITextPosition *pos = [_textField positionFromPosition:_textField.endOfDocument
                                               inDirection:UITextLayoutDirectionLeft
                                                    offset:1];

    //make a 0 length range at position
    UITextRange *newRange = [_textField textRangeFromPosition:pos
                                                toPosition:pos];

    //select it to move cursor
    _textField.selectedTextRange = newRange;
}

回答2:

Swift 3

I came across this question originally because I was wondering how to convert UITextPosition to an Int (based on your title). So that is what I will answer here. You can get an Int for the current text position like this:

if let selectedRange = textField.selectedTextRange {
    // cursorPosition is an Int
    let cursorPosition = textField.offset(from: textField.beginningOfDocument, to: selectedRange.start)
}

For setting the cursor position and other related tasks, see my fuller answer.

来源：https://stackoverflow.com/questions/19369438/uitextposition-to-int