user-input

I want to allow users only to type certain characters based on the a regex in my android applications. How do I achieve it? Ragunath Jawahar Used a TextWatcher as @Matt Ball suggested. @Override public void afterTextChanged(Editable s) { String text = s.toString(); int length = text.length(); if(length > 0 && !Pattern.matches(PATTERN, text)) { s.delete(length - 1, length); } } Edit Although the TextWatcher works, it would be cleaner to use an InputFilter . Check this example . Try this: If the character to type matches /[a-zA-Z0-9{insert valid characters here}]/ then allow it, otherwise don't.

I am trying to build a custom text input for phone numbers that accepts only numbers and the plus (+) symbol; all other characters need to be discarded and not shown on the field. I am trying to do this using an event handler (onkeydown/onkeypress) and discarding inputs corresponding to other keys. However, I can't figure out a cross-browser way to do it. Here are the approaches that I have tried and don't work: Using the onkeypress event and looking at event.key to figure out which key was pressed: doesn't work on Chrome (see http://caniuse.com/keyboardevent-key ). Is there any cross-browser

a = raw_input('How much is 1 share in that company? ') while not a.isdigit(): print("You need to write a number!\n") a = raw_input('How much is 1 share in that company? ') This only works if the user enters an integer , but I want it to work even if they enter a float , but not when they enter a string . So the user should be able to enter both 9 and 9.2 , but not abc . How should I do it? Use regular expressions. import re p = re.compile('\d+(\.\d+)?') a = raw_input('How much is 1 share in that company? ') while p.match(a) == None: print "You need to write a number!\n" a = raw_input('How much

I am looking for a way to 'fix' a dollar symbol $ to a text input box eg <input type="text" value="$" /> but make it not possible for the default value to be removed, so that whatever the user inputs, there is always a $ symbol 'prepending' input. Cheers There is the possibility of a background-image but it's difficult to maintain, and doesn't react to font size changes, which makes it the less optimal choice IMO. A better way in my opionion would be: Put a <span>$</span> next to the input (before it, actually). give it position: relative; left: 20px . The $ sign then moves into the input