Animate UIImageView by Set Distance

Question

I am trying to move an image view forward by a set distance but can't seem to get it working. My turnRight and turnLeft methods work fine. I'm just having issues with the moveForward method. Here is what I'm trying:

- (IBAction)moveForward:(id)sender
{
    if (turtle.image.imageOrientation == UIImageOrientationRight)
    {
        turtle.frame = CGRectMake(turtle.frame.origin.x + 10, turtle.frame.origin.y, 75, 75);
    }
    else if (turtle.image.imageOrientation == UIImageOrientationLeft)
    {
        turtle.frame = CGRectMake(turtle.frame.origin.x - 10, turtle.frame.origin.y, 75, 75);
    }
    else if (turtle.image.imageOrientation == UIImageOrientationUp)
    {
        turtle.frame = CGRectMake(turtle.frame.origin.x, turtle.frame.origin.y + 10, 75, 75);
    }
    else if (turtle.image.imageOrientation == UIImageOrientationDown)
    {
        turtle.frame = CGRectMake(turtle.frame.origin.x, turtle.frame.origin.y - 10, 75, 75);
    }
}

- (IBAction)turnRight:(id)sender
{   
    UIImage *newImage;

    switch (turtle.image.imageOrientation)
    {
        case UIImageOrientationUp:
            newImage = [UIImage imageWithCGImage:[turtle.image CGImage] scale:1.0f orientation:UIImageOrientationRight];
            turtle.contentMode = UIViewContentModeScaleAspectFit;
            break;
        case UIImageOrientationLeft:
            newImage = [UIImage imageWithCGImage:[turtle.image CGImage]scale:1.0f orientation:UIImageOrientationUp];
            turtle.contentMode = UIViewContentModeScaleAspectFill;
            break;
        case UIImageOrientationDown:
            newImage = [UIImage imageWithCGImage:[turtle.image CGImage] scale:1.0f orientation:UIImageOrientationLeft];
            turtle.contentMode = UIViewContentModeScaleAspectFit;
            break;
        case UIImageOrientationRight:
            newImage = [UIImage imageWithCGImage:[turtle.image CGImage]scale:1.0f orientation:UIImageOrientationDown];
            turtle.contentMode = UIViewContentModeScaleAspectFill;
            break;
        default:
            break;
    }
    turtle.image = newImage;
}

- (IBAction)turnLeft:(id)sender
{
    UIImage *newImage;

    switch (turtle.image.imageOrientation)
    {
        case UIImageOrientationUp:
            newImage = [UIImage imageWithCGImage:[turtle.image CGImage] scale:1.0f orientation:UIImageOrientationLeft];
            turtle.contentMode = UIViewContentModeScaleAspectFit;
            break;
        case UIImageOrientationLeft:
            newImage = [UIImage imageWithCGImage:[turtle.image CGImage]scale:1.0f orientation:UIImageOrientationDown];
            turtle.contentMode = UIViewContentModeScaleAspectFill;
            break;
        case UIImageOrientationDown:
            newImage = [UIImage imageWithCGImage:[turtle.image CGImage] scale:1.0f orientation:UIImageOrientationRight];
            turtle.contentMode = UIViewContentModeScaleAspectFit;
            break;
        case UIImageOrientationRight:
            newImage = [UIImage imageWithCGImage:[turtle.image CGImage]scale:1.0f orientation:UIImageOrientationUp];
            turtle.contentMode = UIViewContentModeScaleAspectFill;
            break;
        default:
            break;
    }
    turtle.image = newImage;
}

Answer 1

There are 2 things to consider here.

1) Make sure you are making UI changes on the main thread.
2) Use UIView's animation methods

- (IBAction)moveForward:(id)sender
{
    CGRect frame = turtle.frame;
    switch (turtle.image.imageOrientation)
    {
        case UIImageOrientationUp:
            frame.origin.y + 10; 
            break;
        case UIImageOrientationLeft:
            frame.origin.x - 10;
            break;
        case UIImageOrientationDown:
            frame.origin.y + 10;
            break;
        case UIImageOrientationRight:
            frame.origin.x + 10;
            break;
        default:
            break;
    }

    [UIView animateWithDuration:1.0 // The duration in seconds for the animation to complete.
                 animations:^{
                     turtle.frame = frame;
                 }];
}