Question

I’m trying to do an animation where when a person clicks from point A to Point B on screen the object should slowly slide straight across (horizontally) from point A to Point B.
I’m new at animations by the way.

        [UIView animateWithDuration:10
                              delay:0
                            options:nil
                         animations:^ {

                             if(magnifier != nil){
                                 [magnifier removeFromSuperview];

                             }

                             magnifier = [[MagnifierView alloc] init];

                             magnifier.viewToMagnify = imageView;
                             magnifier.touchPoint = newPoint;
                             [imageView addSubview:magnifier];
                             [magnifier setNeedsDisplay];                             
                         } 
                         completion:nil]; 

but for some reason it is moving it way up and then eventually to point B. sort of in a weird curve.

how can I do this correctly?

Answer 1

Don’t use a loop. Just use the animation block that you have.

• Before the block, set the object to point A.
• In the block, set it to point B. The block will cause it to animate.
• Also, initialize your object outside the animation block.

Example:

// initialize your object outside the block
magnifier = [[MagnifierView alloc] init];
[magnifier setFrame:CGRectMake(0, 0, 100, 100)]; // for example, start at 0, 0 (width and height set to 100 for demo purposes)
[imageView addSubview:magnifier];

[UIView animateWithDuration:10
 delay:0
 options:nil 
 animations:^ {

    // inside the animation block, put the location you want the magnifier to move to
    [magnifier setFrame:CGRectMake(500, 0, 100, 100)]; // for example, move to 500, 0

} 
completion:^(BOOL finished) {

    // do anything you need after here

}];

Also for options you can set UIViewAnimationOptionCurveEaseInOut if you want an easing effect at the beginning and end of the animation or UIViewAnimationOptionCurveLinear if you want an equally timed animation with no easing (there are others available, look up UIViewAnimationOptions).