移动UIImageView移动整个视图

Question

So I'm attempting to make some blocks (called obstacles) fall from the top of the screen. This works, but my code moves the entire view down as well...

ViewController.h:

@interface ViewController : UIViewController{
IBOutlet UIImageView * obstacle;
IBOutlet UIImageView * block;
NSTimer * obstacleTimer;
NSTimer * obMoveTimer;
}
-(void)obTimer;
-(void)moveOb;

ViewController.m:

- (void)obTimer{
UIImageView *cloneImageView = [[UIImageView alloc] initWithImage:obstacle.image];
cloneImageView.frame = CGRectMake(0, -20, obstacle.frame.size.width,     obstacle.frame.size.height);
cloneImageView.alpha = obstacle.alpha;
cloneImageView.layer.opacity = obstacle.layer.opacity;
cloneImageView.clipsToBounds = obstacle.clipsToBounds;
cloneImageView.backgroundColor = obstacle.backgroundColor;
cloneImageView.tintColor = obstacle.tintColor;
cloneImageView.contentMode = obstacle.contentMode;
cloneImageView.highlighted = obstacle.highlighted;
cloneImageView.opaque = obstacle.opaque;
cloneImageView.userInteractionEnabled = obstacle.userInteractionEnabled;
cloneImageView.multipleTouchEnabled = obstacle.multipleTouchEnabled;
cloneImageView.autoresizesSubviews = obstacle.autoresizesSubviews;
cloneImageView.layer.zPosition = obstacle.layer.zPosition+1;
cloneImageView.tag = numOb + 1;
numOb++;
cloneImageView.hidden = NO;
[obstacle.superview addSubview:cloneImageView];
}
- (void)moveOb{
    for (int i = 0; i <= numOb; i++){
        UIImageView *viewToAnimate = (UIImageView *)[obstacle.superview viewWithTag:i];
        viewToAnimate.center = CGPointMake(viewToAnimate.center.x, viewToAnimate.center.y + 1);
    }
}
- (void)viewDidLoad {
    obstacleTimer = [NSTimer scheduledTimerWithTimeInterval:3 target:self         selector:@selector(obTimer) userInfo:nil repeats:YES];
    obMoveTimer = [NSTimer scheduledTimerWithTimeInterval:0.05 target:self     selector:@selector(moveOb) userInfo:nil repeats:YES];
    obstacle.hidden = YES;
    [super viewDidLoad];
}

So the blue blocks are falling down and so is the whole view. Here is a picture:

Answer 1

Those tags are likely to cause you a problem. By default, a UIView has a tag of 0. So when you called up viewWithTag , are you sure you're getting the obstacle you want?

I've used tags many a time, often for different things in the same view. typically for that I would #define a TAG_START_ macro for that purpose, and space them out, sort of like

#define TAG_START_OBSTACLE 10000

And every time I would assign a tag, I would use

NSInteger tag = indexIWantToUse + TAG_START_OBSTACLE;

And to regain the index,

NSInteger index = tag - TAG_START_OBSTACLE;

Though I must say, because I don't see the definition for obstacle here, I would think there's a better way to get the container UIView than using obstacle.superview . Perhaps the UIViewController 's view property? A container within that, or some IBOutlet you can keep a pointer to?