Getting and Setting Cursor Position of Uitextfield and Uitextview in Swift

Getting and Setting Cursor Position of UITextField and UITextView in Swift

The following content applies to both UITextField and UITextView.

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.offset(from: textField.beginningOfDocument, to: 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.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)
}

Related

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")

Notes

  • 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.

See also

  • How to Create a Range in Swift

How to find the cursor Y position in an UITextView having multiple lines as word wraps?

You can get the cursor's CGPoint (X and Y position) within a UITextView in different ways. But do you need to find the position of cursor in relation to self.view (or phone screen borders)? If so, I translated this answer to C# for you:

var textView = new UITextView();
UITextRange selectedRange = textView.SelectedTextRange;
if (selectedRange != null)
{
// `caretRect` is in the `textView` coordinate space.
CoreGraphics.CGRect caretRect = textView.GetCaretRectForPosition(selectedRange.End);

// Convert `caretRect` in the main window coordinate space.
// Passing `nil` for the view converts to window base coordinates.
// Passing any `UIView` object converts to that view coordinate space.
CoreGraphics.CGRect windowRect = textView.ConvertRectFromCoordinateSpace(caretRect, null);
}
else
{
// No selection and no caret in UITextView.
}

Recommended Way to Temporarily Store Text and Cursor Position for UITextView When Backgrounded

I recommend using userdefaults to save short temporary data. When the user backgrounds the application you can set a notification to go off and your viewcontroller can observe for the notification. You can also use the same notification to fetch the text data from userdefaults and show it on textView

Getting the cursor position of UITextField in ios

UITextField conforms to the UITextInput protocol which has methods for getting the current selection. But the methods are complicated. You need something like this:

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
if (textField.tag == 201) {
UITextRange *selRange = textField.selectedTextRange;
UITextPosition *selStartPos = selRange.start;
NSInteger idx = [textField offsetFromPosition:textField.beginningOfDocument toPosition:selStartPos];

[myclass selectTextForInput:textField atRange:NSMakeRange(idx, 0)];
}
}


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