How to use performSelector: withObject: afterDelay: according to a method with several arguments

Question

Let's say I have a method with this signature:

 -(void)plotPoly:(Polygon *)poly WithColor:(UIColor *)color AndFill:(BOOL)filled;

How do I get UIColor and BOOL , as well as a Polygon ?

Should I wrap them in an NSArray and pull them inside the called method? That means I need to change the sig method, right?

Is there a more elegant way to do this?

Answer 1

I answered a rather similar question a few weeks ago. The answer to this question has been edited for this question.

, NSInvocation . , , , , .

, :

 -(void)plotPoly:(Polygon *)poly WithColor:(UIColor *)color AndFill:(BOOL)filled;

:

 -(void)plotPoly:(Polygon *)aPoly color:(UIColor *)aColor filled:(BOOL)filledFlag;

.

, , , -invoke.

- :

PolyPlotter.h:

@interface  PolyPlotter : NSObject
{
    Polygon *poly;
    UIColor *color;
    BOOL filled;
}

+ plotterWithPoly: (Polygon *) aPoly color: (UIColor *) aColor filled: (BOOL) filledFlag; 

- (void) plot;
@end

PolyPlotter.m:

@interface PolyPlotter()
@property Polygon *poly;
@property UIColor *color;
@property BOOL filled;
@end

@implementation PolyPlotter
@synthesize poly, color, filled;

+ plotterWithPoly: (Polygon *) aPoly color: (UIColor *) aColor filled: (BOOL) filledFlag; 
{
    PolyPlotter *polygonPlotter = [PolyPlotter new];
    polygonPlotter.poly = aPoly;
    polygonPlotter.color = aColor;
    polygonPlotter.filled = filledFlag;
    return [polygonPlotter autorelease];
}

- (void) plot;
{
    // ... do your plotting here ...
}
@end

. PolygonPlotter plot - .

, , ? , -plot, , :

- (void) plot: (UIView *) aViewToPlotIn;

- .

, , , NSInvocation. , PolygonPlotter -, .

Answer 2

, , , API, - NSInvocation:

Polygon *poly;
UIColor *color;
BOOL filled;
// Assume the above variables exist
NSInvocation *inv = [NSInvocation invocationWithMessageSignature:[target messageSignatureForSelector:message]];
[inv setArgument:&poly atIndex:2];
[inv setArgument:&color atIndex:3];
[inv setArgument:&filled atIndex:4];
[inv performSelector:@selector(invokeWithTarget:) withObject:target afterDelay:1];

, , , (, ), , .

Answer 3

Joe Hewitt Three20 performSelector, ( ):

- (id)performSelector:(SEL)selector withObject:(id)p1 withObject:(id)p2 withObject:(id)p3 {
  NSMethodSignature *sig = [self methodSignatureForSelector:selector];
  if (sig) {
    NSInvocation* invo = [NSInvocation invocationWithMethodSignature:sig];
    [invo setTarget:self];
    [invo setSelector:selector];
    [invo setArgument:&p1 atIndex:2];
    [invo setArgument:&p2 atIndex:3];
    [invo setArgument:&p3 atIndex:4];
    [invo invoke];
    if (sig.methodReturnLength) {
      id anObject;
      [invo getReturnValue:&anObject];
      return anObject;
    } else {
      return nil;
    }
  } else {
    return nil;
  }
}

NSObject.

Answer 4

I believe NSArray is a smart solution, and yes, that would mean replacing the method signature with NSArray * as the only argument.