I would like to ask the group if this is "good practice" ( I am almost
certain it is not "best practice" :-) )
My question pertains to knowingly setting an object to NULL and then knowingly
sending it a message as an acceptable technique. (If this is not done, drawRect
will simply show the oval as if it was still being actively drawn).
The challenge was to design a doc based app that allowed a user to draw
arbitrary ovals.
Very briefly, I used the outline of "Cocoa design patterns" by using an NSArray
of objects in a "controller" object ( in this case "MyDocument") which defined
a bezierpath, and in the "drawRect" method of the view, used this code.
- (void)drawRect:(NSRect)dirtyRect {
....code to fill background of viewObject....
/* now load the stored ovals from the array */
for (NSBezierPath * oval in [[ self delegate] ovals])
{
....code to set saved color....
[oval fill];
}
/*paint the currently drawn user path (where currentPath is an ivar in the
NSView Object) */
..code to change color to "working" color ....
[[self currentPath] fill];
}
Now...In order to provide visual feedback on the mouseUp event ( the oval
changes color to show that it is now saved) I set the current path to NULL thus.
- (void)mouseUp:(NSEvent *)theEvent
{
....code that sets the current mouseDown point and creates the current
bezier path.....
...code that adds the current bezierpath to ovals list .....
[self setCurrentPath:NULL]; /*sets the current bezierPath to nil */
[self setNeedsDisplay:YES];
As mentioned above, this does work, but seems ?sloppy?.
Thanks.
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