Slide up UIView following finger similar to Control Center in iOS - ios

Question

I have a UITableView that is at the bottom of my main UIViewController, it currently only shows the top two rows. To show the rest I don't want it to scroll, I want the user to be able to "pull" the view up to reveal the additional 4 rows (can then swipe down on it to "push" it back into its original place), and I want the "pull" to be similar to how control center works in iOS. The spring that it has is really great.
Looks like I can add a UIPanGestureRecognizer to do the pull:
UIPanGestureRecognizer * pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(pan:)];
pan.maximumNumberOfTouches = pan.minimumNumberOfTouches = 1;
[self addGestureRecognizer:pan];
- (void)pan:(UIPanGestureRecognizer *)aPan; {
CGPoint currentPoint = [aPan locationInView:self];
[UIView animateWithDuration:0.01f
animations:^{
CGRect oldFrame = _viewToChange.frame;
_viewToChange.frame = CGRectMake(oldFrame.origin.x, currentPoint.y, oldFrame.size.width, ([UIScreen mainScreen].bounds.size.height - currentPoint.y));
}];
}
Ref this question.
Doing this does sort of work, but my UITableView flashes as you pull it up and it eventually disappears.
There is also no spring, and no way to set a "max" so that you can't pull up the view past a certain point.
Does anyone have ideas on how this can be achieved?

Answer 1

this is how i write the pan:. t is tableView(initially user interaction is disabled). 40 in code is for more realistic look in pan. 200 is max value i used and 60 is min value. i directly add t to tableview with height 60 and increased the height with animation.
- (void)pan:(UIPanGestureRecognizer *)aPan; {
CGPoint currentPoint = [aPan locationInView:self.view];
CGRect fr = t.frame;
if ((currentPoint.y - fr.origin.y) < 40 && (fr.size.height <= 200) )
{
float nh = (currentPoint.y >= self.view.frame.size.height - 200) ? self.view.frame.size.height-currentPoint.y : 200;
if (nh < 60) {
nh = 60;
}
[UIView animateWithDuration:0.01f animations:^{
[t setFrame:CGRectMake(0, self.view.frame.size.height-nh, t.frame.size.width, nh)];
}];
if (nh == 200) {
[t setUserInteractionEnabled:YES];
}
else
{
[t setUserInteractionEnabled:NO];
}
}
}
or without pan; with using tableview's scrollview delegate methods, when tableview begin dragging in closed state, opening the large mode and when tableview scroll to top sliding down
-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
NSLog(#"scroll");
if (scrollView.contentOffset.y == 0) {
[UIView animateWithDuration:0.2f animations:^{
[scrollView setFrame:CGRectMake(0, self.view.frame.size.height-200, t.frame.size.width, 200)];
}];
}
}
-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
if (scrollView.contentOffset.y == 0) {
[UIView animateWithDuration:0.2f animations:^{
[scrollView setFrame:CGRectMake(0, self.view.frame.size.height-60, t.frame.size.width, 60)];
}];
}
}