I've been experimenting with UITextField
and how to work with it's cursor position. I've found a number of relation Objective-C answers, as in
But since I am working with Swift, I wanted to learn how to get the current cursor location and also set it in Swift.
The answer below is the the result of my experimentation and translation from Objective-C.
The following content applies to both UITextField
and UITextView
.
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
if let selectedRange = textField.selectedTextRange {
let cursorPosition = textField.offset(from: textField.beginningOfDocument, to: selectedRange.start)
print("\(cursorPosition)")
}
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.textRange(from: newPosition, to: newPosition)
To the end
let newPosition = textField.endOfDocument
textField.selectedTextRange = textField.textRange(from: newPosition, to: 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.position(from: selectedRange.start, offset: -1) {
// set the new position
textField.selectedTextRange = textField.textRange(from: newPosition, to: newPosition)
}
}
To an arbitrary position
Start at the beginning and move 5 characters to the right.
let arbitraryValue: Int = 5
if let newPosition = textField.position(from: textField.beginningOfDocument, offset: arbitraryValue) {
textField.selectedTextRange = textField.textRange(from: newPosition, to: newPosition)
}
Select all text
textField.selectedTextRange = textField.textRange(from: textField.beginningOfDocument, to: textField.endOfDocument)
Select a range of text
// Range: 3 to 7
let startPosition = textField.position(from: textField.beginningOfDocument, offset: 3)
let endPosition = textField.position(from: textField.beginningOfDocument, offset: 7)
if startPosition != nil && endPosition != nil {
textField.selectedTextRange = textField.textRange(from: startPosition!, to: endPosition!)
}
Insert text at the current cursor position
textField.insertText("Hello")
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.