To create a custom spinner create a custom view with the following initialization method

- (id)initWithFrame:(CGRect)frame superViewFrame:(CGRect)superViewFrame
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code

        self.layer.cornerRadius = frame.size.height/2;
        self.backgroundColor = [UIColor grayColor];
        self.layer.borderColor = [UIColor grayColor].CGColor;


        height = superViewFrame.size.height/2;
        center = CGPointMake(height, height);

        count = 0;
        x = 0;
    }
    return self;
}

Now create a method which will rotate custom view in circular path

-(void)fameForView{
    count += 3;

    if (count >= 180) {

        count = 0;
    }
    x = sinf(DEGREES_TO_RADIANS(count))*height*2;

    if (x < 0) {
        x = 0;
    }


    CGFloat pwr;

    pwr = sqrt((powf(height,2) - powf((x - center.x), 2)));

    BOOL isRotating = YES;
    if (count >= 90) {
        isRotating = NO;
    }


    if (isRotating) {

        y = center.y - pwr;
    }else{

        y = center.y + pwr;
    }


    CGFloat decreaseSize = 1.0/(8.0);
    CGRect frame = self.frame;
    if (x != 0) {
        frame.size.width -= decreaseSize;
        frame.size.height -= decreaseSize;

    }else{

        frame.size.width = 15;
        frame.size.height = 15;
    }
    [self setFrame:frame];
    self.center = CGPointMake(x, y);  
}

add animation while rotating the custom view with following method

-(void)animateView{
    [UIView animateWithDuration:0.02 animations:^{

            [self fameForView];


    } completion:^(BOOL finished) {
        [self animateView];
    }];
}

Happy coding......