How to enable “tap and slide” in a UISlider?

Question

What I want to get is a UISlider which lets the user not only slide when he starts on its thumbRect, but also when he taps elsewhere. When the user

Answer 1

I completed @DWilliames solution for a UISlider subclass containing minimum and maximumValueImages.

Additionally I implemented a functionality for user touches in the areas outside the trackArea (means either the area around the minimum or the maximumValueImage). Touching these areas moves the slider/changes the value in intervals.

- (void) tapAndSlide: (UILongPressGestureRecognizer*) gesture {
    CGPoint touchPoint = [gesture locationInView: self];
    CGRect trackRect = [self trackRectForBounds: self.bounds];
    CGFloat thumbWidth = [self thumbRectForBounds: self.bounds trackRect: trackRect value: self.value].size.width;
    CGRect trackArea = CGRectMake(trackRect.origin.x, 0, trackRect.size.width, self.bounds.size.height);
    CGFloat value;

if (CGRectContainsPoint(trackArea, touchPoint)) {
    if (touchPoint.x <= trackArea.origin.x + thumbWidth/2.0) {
        value = self.minimumValue;
    }
    else if (touchPoint.x >= trackArea.origin.x + trackArea.size.width - thumbWidth/2.0) {
        value = self.maximumValue;
    }
    else {
        CGFloat percentage = (touchPoint.x - trackArea.origin.x - thumbWidth/2.0)/(trackArea.size.width - thumbWidth);
        CGFloat delta = percentage*(self.maximumValue - self.minimumValue);
        value = self.minimumValue + delta;
    }

    if (value != self.value) {
        if (gesture.state == UIGestureRecognizerStateBegan) {
            [UIView animateWithDuration: 0.2 delay: 0 options: UIViewAnimationOptionCurveEaseInOut animations: ^{
                [self setValue: value animated: YES];

            } completion: ^(BOOL finished) {
                [self sendActionsForControlEvents: UIControlEventValueChanged];
            }];
        }
        else {
            [self setValue: value animated: YES];
            [self sendActionsForControlEvents: UIControlEventValueChanged];
        }
    }
}
else {
    if (gesture.state == UIGestureRecognizerStateBegan) {
        if (touchPoint.x <= trackArea.origin.x) {
            if (self.value == self.minimumValue) return;
            value = self.value - 1.5;
        }
        else {
            if (self.value == self.maximumValue) return;
            value = self.value + 1.5;
        }
        CGFloat duration = 0.1;
        [UIView animateWithDuration: duration delay: 0 options: UIViewAnimationOptionCurveEaseInOut animations: ^{
            [self setValue: value animated: YES];
        } completion: ^(BOOL finished) {
            [self sendActionsForControlEvents: UIControlEventValueChanged];
        }];
    }
}
}