Re: NSTextField with NSLevelIndicator

FROM : Andy Lee
DATE : Mon Apr 28 23:53:09 2008

Yup, that's right.

An object that has a delegate sends certain pre-defined messages to 
the delegate at certain times.  Those times are described by the name 
of the delegate method.  For example, "controlTextDidChange:" is sent 
after the text in an NSControl changes.  The naming convention is very 
consistent throughout Cocoa.  Delegate methods sound almost like 
newspaper headlines: "window will close", "file manager should proceed 
after error", etc.

You can see the list of delegate methods an object supports by looking 
at its class documentation.  You wouldn't have found -
controlTextDidChange: by looking at NSTextField, but by going up the 
inheritance hierarchy you would have found NSControl's delegate methods.

The delegate contract is quite relaxed.  If the object's delegate is 
nil, it doesn't send any delegate messages.  If the delegate doesn't 
implement all the delegate methods, only the messages that are 
implemented are sent.  The delegate can be an instance of any class -- 
all that matters is what methods it implements.  So you can implement 
only what you need.

--Andy

On Apr 28, 2008, at 5:06 PM, Philip Bridson wrote:

> Ok. Thanks for the reply - this may sound stupid but I haven't dealt
> with delegates much. If I make the window controller the delegate
> would I just declare a method in that window controller's files as
> below?
>
> - (void)controlTextDidChange:(NSNotification)notification
> {
> runMyFunction();
> }
>
> Sorry if I seem stupid but as I say I don't use them much.
>
> Thanks,
>
> Phil
>
> On Monday, April 28, 2008, at 08:34PM, "Andy Lee" <<email_removed>> 
> wrote:

>> Give your text field a delegate, and in the delegate implement -
>> controlTextDidChange:.
>>
>> See the docs for more details.
>>
>> --Andy
>>
>> On Apr 28, 2008, at 3:17 PM, Philip Bridson wrote:
>>

>>> Hi there,
>>>
>>> I want to create a password analysis tool that updates an
>>> NSLevelIndicator with each character entered into a
>>> NSSecureTextField. I know how to update the NSLevelIndicator once 
>>> the
>>> user has finished entering text but how do i update it per 
>>> character?
>>>
>>> To give you a bit more info:
>>>
>>> The text is passed to a function: the function returns a value: the
>>> value is used to update the level indicator.
>>>
>>> This works fine but I can only do it once the whole word is in the
>>> field. How do I pass characters as they are entered to my func? Such
>>> as:
>>>
>>> 1. P
>>> 2. Pa
>>> 3. Pas
>>> 4. Pass
>>> 5. Passw
>>> 6. Passwo
>>> 7. Passwor
>>> 8. Password
>>>
>>> Thank you for any help you might give.
>>>
>>> Phil.

>>>>
>>>>

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