Control cursor position in UITextField

Question

I have a UITextField that I\'m forcing formatting on by modifying the text inside the change notification handler. This works great (once I solved the reentranc

Answer 1

Here's the Swift version of @Chris R. – updated for Swift3

private func selectTextForInput(input: UITextField, range: NSRange) {
    let start: UITextPosition = input.position(from: input.beginningOfDocument, offset: range.location)!
    let end: UITextPosition = input.position(from: start, offset: range.length)!
    input.selectedTextRange = input.textRange(from: start, to: end)
}

Answer 2

Controlling cursor position in a UITextField is complicated because so many abstractions are involved with input boxes and calculating positions. However, it's certainly possible. You can use the member function setSelectedTextRange:

[input setSelectedTextRange:[input textRangeFromPosition:start toPosition:end]];

Here's a function which takes a range and selects the texts in that range. If you just want to place the cursor at a certain index, just use a range with length 0:

+ (void)selectTextForInput:(UITextField *)input atRange:(NSRange)range {
    UITextPosition *start = [input positionFromPosition:[input beginningOfDocument] 
                                                 offset:range.location];
    UITextPosition *end = [input positionFromPosition:start
                                               offset:range.length];
    [input setSelectedTextRange:[input textRangeFromPosition:start toPosition:end]];
}

For example, to place the cursor at idx in the UITextField input:

    [Helpers selectTextForInput:input 
                        atRange:NSMakeRange(idx, 0)];

Answer 3

Useful to position at index (Swift 3)

private func setCursorPosition(input: UITextField, position: Int) {
    let position = input.position(from: input.beginningOfDocument, offset: position)!
    input.selectedTextRange = input.textRange(from: position, to: position)
}

Answer 4

Here is a snippet which works fine for this problem:

- (void)textFieldDidBeginEditing:(UITextField *)textField{
    UITextPosition *positionBeginning = [textField beginningOfDocument];
    UITextRange *textRange =[textField textRangeFromPosition:positionBeginning 
                                                  toPosition:positionBeginning];
    [textField setSelectedTextRange:textRange];
}

Source from @omz

Answer 5

Feel free to use this UITextField category to get and set cursor position:

@interface UITextField (CursorPosition)

@property (nonatomic) NSInteger cursorPosition;

@end

–

@implementation UITextField (CursorPosition)

- (NSInteger)cursorPosition
{
    UITextRange *selectedRange = self.selectedTextRange;
    UITextPosition *textPosition = selectedRange.start;
    return [self offsetFromPosition:self.beginningOfDocument toPosition:textPosition];
}

- (void)setCursorPosition:(NSInteger)position
{
    UITextPosition *textPosition = [self positionFromPosition:self.beginningOfDocument offset:position];
    [self setSelectedTextRange:[self textRangeFromPosition:textPosition toPosition:textPosition]];
}

@end

Answer 6

I've finally found a solution for this problem! You can put the text you need inserted into the system pasteboard and then paste it at the current cursor position:

[myTextField paste:self]  

I found the solution on this person's blog:
http://dev.ragfield.com/2009/09/insert-text-at-current-cursor-location.html

The paste functionality is OS V3.0 specific, but I've tested it and it works fine for me with a custom keyboard.

If you go for this solution then you should probably save the user's existing clipboard contents and restore them immediately afterwards.