I've got a few UITextFields in an UITableView. The user should be able to insert only numbers and dots. To do this, I set the keyboard type to UIKeyboardTypeNumberPad and added a '.'-Button at the bottom left corner. Every time the button is pressed, a function is called. This function should insert a dot at the current cursor position, but this is the problem: UITextField hasn't got an selectedRange property, so I'm not able to get the current cursor position. Does anybody know how to solve this problem or is there any other way to do this? Thanks.
12
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6 Answers
33
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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.
Update: As per Jasarien's comment below, it is good practice to save off the pasteboard contents first and restore them afterward. For convenience, here is my code:
// Get a reference to the system pasteboard
UIPasteboard* lPasteBoard = [UIPasteboard generalPasteboard];
// Save the current pasteboard contents so we can restore them later
NSArray* lPasteBoardItems = [lPasteBoard.items copy];
// Update the system pasteboard with my string
lPasteBoard.string = @"-";
// Paste the pasteboard contents at current cursor location
[myUIField paste:self];
// Restore original pasteboard contents
lPasteBoard.items = lPasteBoardItems;
[lPasteBoardItems release];
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4
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In Swift
This inserts text at the current cursor position.
textField.insertText("Hello")
My full answer about working with the cursor position is here.
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There is now a fantastic number pad type keyboard that includes a decimal point, no configuration necessary except setting (not in IB, not an option there yet) the UITextField's keyboardType property to UIKeyboardStyleDecimalPad, like so:
textField.keyboardType = UIKeyboardTypeDecimalPad;
This does all the fancy stuff you've been trying to do automatically.
1
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If you're looking to create text fields that allow you to enter decimal places may I suggest that you rather fix the decimal point to a certain precision and allow the user to enter numbers as follows:
Assuming your precision is 2 decimal points:
start: value is 0.00
user enters 1: value is 0.01
user enters 2: value is 0.12
user enters 3: value is 1.23
user enters 4: value is 12.34
See What is the best way to enter numeric values with decimal points? for a similar solution for currency.
It is by far a more simple solution than creating a custom keyboard and dealing with all the nuances that that approach presents. If, however, you need variable length precision then that approach might suite you better.
