zPosition example, a bit wordy.

gistfile1.txt

//
// C4WorkSpace.m
//
// Created by Travis Kirton and Greg Debicki.
//

#import "C4WorkSpace.h"

@implementation C4WorkSpace {
    NSArray *shapes;
    C4Shape *s1, *s2, *s3;
    C4Label *l1, *l2, *l3;
}

-(void)setup {
    [self setupShapesAndLabels];
    [self listenFor:@"touchesBegan" fromObjects:shapes andRunMethod:@"adjustZPositions:"];
}

-(void)adjustZPositions:(NSNotification *)notification {
    C4Shape *touchedShape = (C4Shape *)[notification object];
    if(touchedShape.zPosition != 3) {
        for(C4Shape *s in shapes) {
            if(s == touchedShape) s.zPosition = 3;
            else s.zPosition = s.zPosition == 1 ? 1 : s.zPosition - 1;
        }
        [self setLabels];
    }
}

-(void)setLabels {
    //FIXME: zPosition should be an integer (maybe)
    l1.text = [NSString stringWithFormat:@"%d",(int)s1.zPosition];
    l2.text = [NSString stringWithFormat:@"%d",(int)s2.zPosition];
    l3.text = [NSString stringWithFormat:@"%d",(int)s3.zPosition];
}

-(void)setupShapesAndLabels {
    //FIXME: shape lineWidth needs fixing
    CGRect frame = CGRectMake(0, 0, 100, 100);
    s1 = [C4Shape ellipse:frame];
    s2 = [C4Shape ellipse:frame];
    s3 = [C4Shape ellipse:frame];
    
    s1.zPosition = 1;
    s2.zPosition = 2;
    s3.zPosition = 3;
    
    s1.center = CGPointMake(self.canvas.center.x - 50, self.canvas.center.y - 50);
    s2.center = self.canvas.center;
    s3.center = CGPointMake(self.canvas.center.x + 50, self.canvas.center.y + 50);
    
    l1 = [C4Label labelWithText:@"1"];
    l1.center = CGPointMake(s1.center.x,s1.center.y + s1.height);
    l2 = [C4Label labelWithText:@"2"];
    l2.center = CGPointMake(s2.center.x,s2.center.y + s2.height);
    l3 = [C4Label labelWithText:@"3"];
    l3.center = CGPointMake(s3.center.x,s3.center.y + s3.height);
    
    shapes = @[s1,s2,s3];
    
    [self.canvas addObjects:shapes];
    [self.canvas addObjects:@[l1,l2,l3]];
}
@end