Oscillating UIView With Stopping Motion (iOS) - iphone

Question

I need a view to enter the screen with oscillating animation and finally, the animation should stop in a natural way (decreasing oscillations - pendulum effect). I have added the subview above the screen so that the view rotates into the screen when required. The code for adding the subview is:
myView.layer.anchorPoint = CGPointMake(1.0, 0.0);
[[self view] addSubview:myView];
[myView setHidden:YES];
// Rotate 75 degrees to hide it off screen
CGAffineTransform rotationTransform = CGAffineTransformIdentity;
rotationTransform = CGAffineTransformRotate(rotationTransform, DEGREES_RADIANS(75));
bannerView.transform = rotationTransform;
bannerView.center = CGPointMake(((self.view.bounds.size.width)/2.0), -5.0);
[self performSelector:#selector(animateSwing) withObject:nil afterDelay:3.0];
The way I'm trying to achieve this that the view should rotate one full semi circle & back rotation, then rotate one semi circle rotation and finally come to halt at desired point using EaseOut animation curve. The code for my animateSwing() method is given below:
- (void)animateSwing {
NSLog(#"ANIMATING");
[myView setHidden:NO];
CGAffineTransform swingTransform = CGAffineTransformIdentity;
swingTransform = CGAffineTransformRotate(swingTransform, DEGREES_RADIANS(-20));
[UIView animateWithDuration:0.30
delay:0.0
options:UIViewAnimationOptionCurveEaseOut
animations:^{
[UIView setAnimationRepeatCount:1.5];
[UIView setAnimationRepeatAutoreverses:YES];
myView.transform = swingTransform;
}completion:^(BOOL finished){
[UIView animateWithDuration:0.10
delay:0.0
options:UIViewAnimationOptionCurveEaseOut
animations:^{
myView.transform = CGAffineTransformMakeRotation(DEGREES_RADIANS(0));
}completion:^(BOOL Finished){
}];
}];
}
For some reason the above code isn't working. If I do not chain animations, the code performs the semi-circle routine. But if I chain animations like above, it just oscillates a little bit around the desired point and ends abruptly.
Please suggest a fix to this code OR suggest a way to implement the required animation
Thanks

Answer 1

You want to use a keyframe animation. I actually have an example of a "decreasing waggle" animation in my book (http://www.apeth.com/iOSBook/ch17.html#_keyframe_animation):
CompassLayer* c = (CompassLayer*)self.compass.layer;
NSMutableArray* values = [NSMutableArray array];
[values addObject: #0.0f];
int direction = 1;
for (int i = 20; i < 60; i += 5, direction *= -1) { // alternate directions
[values addObject: #(direction*M_PI/(float)i)];
}
[values addObject: #0.0f];
CAKeyframeAnimation* anim =
[CAKeyframeAnimation animationWithKeyPath:#"transform"];
anim.values = values;
anim.additive = YES;
anim.valueFunction =
[CAValueFunction functionWithName: kCAValueFunctionRotateZ];
[c.arrow addAnimation:anim forKey:nil];
Of course that isn't identical to what you're trying to do, but it should get you started.