Matlab GUI - Edit text only allow numbers and '.'

I would like to create an edit text that only allows to introduce numbers and '.' . If another letter is pressed it should write nothing.

Using KeyPressFcn I am able to detect the letter pressed and compare to the valid ones but I do not know what to do in order to not to write the character if it is not valid.

Any idea?

Answer 1

[Daniel Shub]

If the key is invlaid you want to set the string of the edit box to be whatever the string is minus the last element

x = get(h, 'String')
set(h, 'String', h(1:end-1))

[Jan]

This wil fail if a string is copied by Ctrl-V.

Answer 2

[Jan]

This behaviour will annoy the user. The limitation of the keyboard feels sticky. Better let the user write anything and check the input in the callback function only, e.g. by:

function myNumberCheck(ObjH, EventData)
S = get(ObjH, 'String');

% Exclude characters, which are accepted by sscanf:
S(ismember(S, '-+eEgG')) = ' ';

% Convert to one number and back to a string:
S2 = sprintf('%g', sscanf(S, '%g', 1));
set(ObjH, 'String', S2);

% Perhaps a small warning in WARNDLG or inside the GUI:
if ~all(ismember(S, '.1234567890'))
  ...
end