Up: W3Kit Class Reference

W3ActionInput

Superclass: W3Input

W3ActionInput is an abstract W3Kit base class representing an input element that holds a value and can notify another object of changes in that value. This "target-action" paradigm comes from OpenStep, and is a convenient way to record a lot of the interface logic in object relationships rather than code. Most of the basic HTML widgets are implemented as subclasses of W3ActionInput.

The target of the W3ActionInput is the object to be notified, while the action is the message that will be sent. The action message should take one object argument (the sender) and return an object value (typically the target which received the message). 

- setAction:(SEL)aSelector;
- (SEL)action;
- setTarget:anObject;
- target;
- sendAction;
The "essential state" of the base W3ActionInput consists of the target, action, and title. The base class provides a standard way to print out the title and current value, for use in printHtml. The current value only gets printed if there is a nonempty title. 
- setTitle:(const char *)aString;
- (const char *)title;
- printHtmlTitle;
The data entered by the user is the "non-essential state" (it gets refreshed every time and so does not have to be remembered explicitly). The data is loosely typed and can be accessed with a variety of methods. The take...From: methods are intended as action messages. 
- takeStringValueFrom:sender;
- takeDoubleValueFrom:sender;
- takeFloatValueFrom:sender;
- takeIntValueFrom:sender;
- setStringValue:(const char *)value;
- setDoubleValue:(double)value;
- setFloatValue:(float)value;
- setIntValue:(int)value;
- (const char *)stringValue;
- (double)doubleValue;
- (float)floatValue;
- (int)intValue;
- setState:(int)value;
- (int)state;

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Author: Paul Burchard
Comments to: webmaster@www.geom.uiuc.edu
Created: Apr 18 1994 --- Last modified: Tue Jun 18 10:40:41 1996