Python for Bioinformatics: Hillegass Challenge: count letters

Monday, July 28, 2008

Hillegass Challenge: count letters

On p. 90, we're instructed to build an app with a Text Field where the user enters a string, and another one which displays the character count of the string. I did this using bindings. The Text Fields are bound to variables "textField" and "count" and we implement setTextField_ with a check for string value of None, which is what we get when we delete the last character of a string in the Text Field. Continuously update value is checked in the binding.

class PyStrLenAppDelegate(NSObject):
    textField = objc.ivar('textField')
    count = objc.ivar('count')
    
    def setTextField_(self,value):
        NSLog("setTextField_ %s" % value)
        if not value:   x = '0'
        else:           x = value.length()
        self.setCount_(x)
    
    def setCount_(self,value):  self.count = value