Show UISearchController on UITableView scroll down - objective-c

Question

I have a UISearchController just over my UITableView and my table has many recrods. When a user goes to bottom in the table, he has to come back to top to see the search bar. Below you can see how I create the search bar:
- (void) showSearchBar {
_searchController = [[UISearchController alloc] initWithSearchResultsController:nil];
self.searchController.searchResultsUpdater = self;
self.searchController.searchBar.placeholder = nil;
[self.searchController.searchBar sizeToFit];
self.tableView.tableHeaderView = self.searchController.searchBar;
//self.sharedNavigationItem.titleView = _searchController.searchBar;
self.searchController.delegate = self;
self.searchController.dimsBackgroundDuringPresentation = NO; // default is YES
self.searchController.searchBar.delegate = self; // so we can monitor text changes + others
self.definesPresentationContext = YES;
_searchController.hidesNavigationBarDuringPresentation = NO;
}
I was wondering how to show the search bar when I scroll down (go up) in the table and hide it back when I scroll up (go down) in the table even I am at the bottom of the table.

Answer 1

The search bar can be placed arbitrarily in the UI. Create a sibling view to the table view, placed -- for example -- above the table. Give that view a height constraint set initially to 44px and provide outlets to both the view and the constraint...
#property(weak,nonatomic) IBOutlet UIView *searchBarContainerView;
#property(weak,nonatomic) IBOutlet NSLayoutConstraint *searchBarHeightConstraint;
Now, your setup code changes to:
// ...
self.searchBarHeightConstraint.constant = self.searchController.searchBar.bounds.size.height;
[self.searchBarContainerView addSubview:self.searchController.searchBar];
// ...

Answer 2

If you make the header stay at top, then the search field should stay visible
UITableViewStylePlain: A plain table view. Any section headers or footers are displayed as inline separators and float when the table view is scrolled.
UITableViewStyleGrouped: A table view whose sections present distinct groups of rows. The section headers and footers do not float.

Answer 3

I trying to help you out with what I did, hope it helps you.
This is how I added my label in header view of table view, I tried to replace it by your search controller;
-(UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {
CGRect frame = CGRectMake(0, 0, tableView.frame.size.width, 40);
UIView *view = [[UIView alloc] initWithFrame:frame];
view.backgroundColor = [UIColor clearColor];
view.autoresizingMask = UIViewAutoresizingFlexibleWidth;
_searchController = [[UISearchController alloc] initWithSearchResultsController:nil];
self.searchController.searchResultsUpdater = self;
self.searchController.searchBar.placeholder = nil;
[self.searchController.searchBar sizeToFit];
[view addSubview:_searchController];
view.tag = 123;
return view;
}
If you wish to hide effect at complete end of dragging move use below method;
-(void)scrollViewWillEndDragging:(UIScrollView *)scrollView
withVelocity:(CGPoint)velocity
targetContentOffset:(inout CGPoint *)targetContentOffset{
if (velocity.y > 0){
NSLog(#"up");
[self.view viewWithTag:123].hidden = true;
}
if (velocity.y < 0){
NSLog(#"down");
[self.view viewWithTag:123].hidden = false;
}
And for immediate changes of scrolling the tableview use below method :
-(void)scrollViewDidScroll:(UIScrollView *)scrollView //working delegate
{
if ([scrollView.panGestureRecognizer translationInView:scrollView].y > 0) {
NSLog(#"down");
[self.view viewWithTag:123].hidden = false;
} else {
NSLog(#"up");
[self.view viewWithTag:123].hidden = true;
}
}

Answer 4

After some searching I thought of some new answer, hope it helps you!
To identify direction of Scroll:
BOOL showSearch;
-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
if ([scrollView.panGestureRecognizer translationInView:scrollView].y > 0) {
// down
showSearch = true;
} else {
// up
showSearch = false;
}
}
-(void)scrollViewWillEndDragging:(UIScrollView *)scrollView
withVelocity:(CGPoint)velocity
targetContentOffset:(inout CGPoint *)targetContentOffset{
if (showSearch) {
[self addSearch];
}
else {
[self removeSearch];
}
[_tableView reloadData];
}
To add & remove SearchController:
-(void)addSearch {
if (!_searchController){
_searchController = [[UISearchController alloc] initWithSearchResultsController:nil];
_searchController.searchResultsUpdater = self;
[_searchController.searchBar sizeToFit];
_tableView.tableHeaderView = _searchController.searchBar;
_searchController.delegate = self;
_searchController.dimsBackgroundDuringPresentation = NO;
self.definesPresentationContext = YES;
_searchController.active = NO;
_searchController.searchResultsUpdater = self;
_searchController.dimsBackgroundDuringPresentation = NO;
self.definesPresentationContext = YES;
_tableView.tableHeaderView = _searchController.searchBar;
_searchController.searchBar.delegate = self;
}
}
-(void)removeSearch {
_searchController.active = NO;
[_searchController removeFromParentViewController];
_searchController = nil;
_tableView.tableHeaderView = nil;
}