Scrollview should start from where I left it last time - ios

Question

I have a scrollview(timesScrollView) which is added as a subview on a view(dropDownView).The view is hidden until a particular button is pressed, when that button is pressed view will appear.
(IBAction)how_many_times_btn_click:(id)sender{
if(howMany==false){
for(UIView *view in dropDownView.subviews)
{
[view removeFromSuperview];
}
howMany=true;
duration=false;
how_many_times_btn.backgroundColor=[UIColor colorWithRed:130/255.0f green:189/255.0f blue:31/255.0f alpha:1.0f];
durationBtn.backgroundColor=[UIColor colorWithRed:62/255.0f green:67/255.0f blue:79/255.0f alpha:1.0f];
startBtn.backgroundColor=[UIColor colorWithRed:62/255.0f green:67/255.0f blue:79/255.0f alpha:1.0f];
dropDownView.hidden=NO;
dropDownView.frame=CGRectMake(0, 0, self.view.frame.size.width,70);
dropDownView.backgroundColor=[UIColor colorWithRed:37/255.0f green:42/255.0f blue:54/255.0f alpha:1.0f];
//dropDownView.backgroundColor=[UIColor whiteColor];
targetLbl=[[UILabel alloc]init];
targetLbl.frame=CGRectMake(0, 30, dropDownView.frame.size.width,30);
targetLbl.text=#"TARGET";
targetLbl.textColor=[UIColor whiteColor];
targetLbl.font=[UIFont boldSystemFontOfSize:22];
targetLbl.textAlignment=NSTextAlignmentCenter;
how_many_Lbl=[[UILabel alloc]init];
how_many_Lbl.frame=CGRectMake(0, targetLbl.frame.origin.y+targetLbl.frame.size.height, dropDownView.frame.size.width, 20);
how_many_Lbl.textAlignment=NSTextAlignmentCenter;
how_many_Lbl.text=#"HOW MANY TIMES WILL YOU DO IT?";
how_many_Lbl.textColor=[UIColor colorWithRed:65/255.0f green:71/255.0f blue:80/255.0f alpha:1.0f];
how_many_Lbl.font=[UIFont systemFontOfSize:10.0f];
hideViewBtn=[UIButton buttonWithType:UIButtonTypeCustom];
hideViewBtn.frame=CGRectMake(dropDownView.frame.size.width-30,20,20,20);
[hideViewBtn setImage:[UIImage imageNamed:#"Close Icon [ x ]"] forState:UIControlStateNormal];
[hideViewBtn addTarget:self action:#selector(hideView) forControlEvents:UIControlEventTouchUpInside];
//hideViewBtn.backgroundColor=[UIColor whiteColor];
self.timesScroll=[[LTInfiniteScrollView alloc] initWithFrame:CGRectMake(0, how_many_Lbl.frame.origin.y+how_many_Lbl.frame.size.height+16, dropDownView.frame.size.width, 102)];
//self.timesScroll.backgroundColor=[UIColor whiteColor];
self.timesScroll.verticalScroll=NO;
self.timesScroll.dataSource=self;
self.timesScroll.maxScrollDistance=5;
self.timesScroll.contentInset=UIEdgeInsetsMake(0, self.timesScroll.frame.size.width/2-31, 0,self.timesScroll.frame.size.width/2-31 );
self.timesScroll.userInteractionEnabled=YES;
self.timesScroll.exclusiveTouch=YES;
dropDownView.frame=CGRectMake(0, 0, self.view.frame.size.width,_timesScroll.frame.origin.y+_timesScroll.frame.size.height+20);
[self viewWillAppear:YES];
[dropDownView addSubview:targetLbl];
[dropDownView addSubview:how_many_Lbl];
[dropDownView addSubview:hideViewBtn];
[dropDownView addSubview:_timesScroll];
}
else
{
[self hideView];
}
}
The method above is what I am using to create view.
Now my problem is that when that particular button(how_many_times_btn) is pressed again all views are first removed then added as you can see and scrollview starts from initial position but I want it show from where I left it last time how_many_times_btn was clicked.
Hope you can understand What I am trying to say....if not I am happy to elaborate furthur.

Answer 1

you can get the last position by delegate methods
-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
nslog(#"%f %f",scrollView.contentOffset.x,scrollView.contentOffset.y);
}
and store the x and y value and set
scrollView.contentOffset = CGPointMake(x,y);

Answer 2

You can save contentOffsetto one variable of CGPoint. And use this variable 's value later to scroll the UIScrollview.
Something like below line of code :
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
contentOffset = scrollView.contentOffset;
}
When button pressed write below line of code:
self.timesScroll .contentOffset = contentOffset;

Answer 3

I'm using LTInfiniteScrollview in which there is a method 'reloadDataWithInitialIndex'
-(void)reloadDataWithInitialIndex:(NSInteger)initialIndex
{
for (UIView *view in self.scrollView.subviews) {
[view removeFromSuperview];
}
self.views = [NSMutableDictionary dictionary];
self.visibleViewCount = [self.dataSource numberOfVisibleViews];
self.totalViewCount = [self.dataSource numberOfViews];
[self updateSize];
_currentIndex = initialIndex;
self.scrollView.contentOffset = [self contentOffsetForIndex:_currentIndex];
[self reArrangeViews];
[self updateProgress];}
This method is called in 'viewWillAppear'
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
self.viewSize = CGRectGetWidth(self.view.frame) / Number_of_visibleViews;
self.timesScroll.delegate=self;
[self.timesScroll reloadDataWithInitialIndex:howIndex];}
I just passed previous index value here.