Updating UI in when consuming RESTful API - ios

Question

I have UI that uses scrollview with paging as well UITableView in one view controller. In order to load UI I am using an array of NSDictionaries (sourceArray) which has necessary information to draw UI. This array is created by consuming RESTful API that returns an array of records. I am returning that array in completion handler. Later I add that array along with some other key:value pairs to create NSDictioary which is later added to sourceArray for UI drawing.
Now my question is how can I update my UI based on changes in sourceArray. I am calling [self.view layoutIfNeeded]; but it does not force redraw.
- (void)getStateDetails {
NSArray *statesArray = [self getStates];
for (NSString *state in statesArray) {
[self getStateDetailsInState:state withCompletionBlock:^(NSArray *records) {
NSLog(#"%#",records);
NSDictionary *dict = #{
#"kImage": state,
#"kName": state,
#"kRecord": records
};
[self.sourceArray addObject:dict];
dispatch_async(dispatch_get_main_queue(), ^{
[self.view layoutIfNeeded];
});
}];
}
}
UI Details-
Viewcontroller contains UIScrollView with various UIViews which used dynamic data and a UITableView that contains dynamic data as well.
This is how I my current UI looks like.

Answer 1

The call to layoutIfNeeded will trigger your views to check to see if they need to update their layouts. Changing the contents of an array will not cause your view's layouts to need updating, so the call to layoutIfNeeded is unlikely to do anything.
In order for us to help you use the dictionary you load to update your UI, you're going to have to tell us what changes you expect the new array element to have on your UI.
One common thing to do is to display the contents of an array in a table view or collectionView. In that case you'd call the table/collection view's reloadData() function, which will cause it to ask it's data source for it's number of entries and re-render all of it's cells.
EDIT
Ok, and what is the relationship between the data you download and your UI? What code have you written that is supposed to cause the UI to update? You've changed your array, but you don't show any code that tells your view objects about updated data.
For a table view, that might be as simple as calling reloadData as mentioned above. For other views, how is your data being displayed into those views? What mechanism is supposed to install new data into those views?

Answer 2

The easiest way to get a view to re-draw itself is to call [UIView setNeedsDisplay] or by using [UIView setNeedsDisplayInRect]. This method tells the view that it needs to re-draw itself and it's subviews. However you shouldn't always have to call this. There are other methods that can cause views to redraw themselves. For instance if you add or remove a view to the view hierarchy using [UIView addSubview:] or [UIView removeFromSuperview].
These methods cause the system to call your view's drawInRect: method (assuming you overrode it with custom drawing code). If you did not override this method for custom drawing then it should cause your subviews to receive the same message so that they can get a chance to redraw.
Additional information here. Specifically read the section labeled "The View Drawing Cycle".
http://developer.apple.com/library/ios/#documentation/uikit/reference/uiview_class/uiview/uiview.html
One of the stackoverflow posts where you can add an observer and force call the controller to relaod
How to reload UIViewController

Answer 3

You have to use [tableView reloadData] and then if needed
[self.view layoutSubviews];
[self.view setNeedsDisplay];
[self.view setNeedsLayout];