iOS UITextField Getting and Setting the Cursor Position
Example
Useful information
The very beginning of the text field text:
let startPosition: UITextPosition = textField.beginningOfDocument
The very end of the text field text:
let endPosition: UITextPosition = textField.endOfDocument
The currently selected range:
let selectedRange: UITextRange? = textField.selectedTextRange
Get cursor position
if let selectedRange = textField.selectedTextRange {
let cursorPosition = textField.offsetFromPosition(textField.beginningOfDocument, toPosition: selectedRange.start)
print("\(cursorPosition)")
}
Set cursor position
In order to set the position, all of these methods are actually setting a range with the same start and end values.
To the beginning
let newPosition = textField.beginningOfDocument
textField.selectedTextRange = textField.textRangeFromPosition(newPosition, toPosition: newPosition)
To the end
let newPosition = textField.endOfDocument
textField.selectedTextRange = textField.textRangeFromPosition(newPosition, toPosition: newPosition)
To one position to the left of the current cursor position
// only if there is a currently selected range
if let selectedRange = textField.selectedTextRange {
// and only if the new position is valid
if let newPosition = textField.positionFromPosition(selectedRange.start, inDirection: UITextLayoutDirection.Left, offset: 1) {
// set the new position
textField.selectedTextRange = textField.textRangeFromPosition(newPosition, toPosition: newPosition)
}
}
To an arbitrary position
Start at the beginning and move 5 characters to the right.
let arbitraryValue: Int = 5
if let newPosition = textField.positionFromPosition(textField.beginningOfDocument, inDirection: UITextLayoutDirection.Right, offset: arbitraryValue) {
textField.selectedTextRange = textField.textRangeFromPosition(newPosition, toPosition: newPosition)
}
Related
Select all text
textField.selectedTextRange = textField.textRangeFromPosition(textField.beginningOfDocument, toPosition: textField.endOfDocument)
Select a range of text
// Range: 3 to 7
let startPosition = textField.positionFromPosition(textField.beginningOfDocument, inDirection: UITextLayoutDirection.Right, offset: 3)
let endPosition = textField.positionFromPosition(textField.beginningOfDocument, inDirection: UITextLayoutDirection.Right, offset: 7)
if startPosition != nil && endPosition != nil {
textField.selectedTextRange = textField.textRangeFromPosition(startPosition!, toPosition: endPosition!)
}
Insert text at the current cursor position
textField.insertText("Hello")
Notes
-
This example originally comes from this Stack Overflow answer.
-
This answer uses a text field, but the same concepts apply to
UITextView. -
Use
textField.becomeFirstResponder()to give focus to the text field and make the keyboard appear. -
See this answer for how to get the text at some range.
Related
- How to Create a Range in Swift (Deals indirectly with the issue of why we have to use
selectedTextRangehere rather than justselectedRange)
