SJOSearchableFetchedResultsController additions

Library/SJOSearchableFetchedResultsController.h

@@ -15,12 +15,32 @@ This class provides a simpler way to replicate the often-used pattern of a searc
  */
 @interface SJOSearchableFetchedResultsController : UITableViewController<UISearchBarDelegate, UISearchDisplayDelegate, NSFetchedResultsControllerDelegate>
 
+/**
+ *  Initialises a Core Data-backed UITableViewController with a configured with a UISearchDispalyController.
+ *
+ *  @param context The managed object context to use when query Core Data.
+ *  @param style   A constant that specifies the style of table view that the controller object is to manage (UITableViewStylePlain or UITableViewStyleGrouped).
+ *
+ *  @return An initialized SJOSearchableFetchedResultsController object or nil if the object couldn’t be created.
+ */
+- (instancetype)initWithContext:(NSManagedObjectContext *)managedObjectContext style:(UITableViewStyle)style;
+
 /**
  The SJODataStore to be used when querying data.
- @warning This must be set before the view is loaded.
+ @warning This must be set before the view is loaded unless constructed with a managed object context.
  */
 @property (strong, nonatomic) SJODataStore *store;
 
+/**
+ *  The managed object context used. If the store property is set this is the `mainContext` of the SJOStore instance.
+ */
+@property (nonatomic, strong, readonly) NSManagedObjectContext *managedObjectContext;
+
+/**
+ *  Returns YES if the user is actively searching, i.e. the search bar has begun editing. Returns NO after the user has cancelled the search.
+ */
+@property(nonatomic, assign, readonly) BOOL searchIsActive;
+
 /**
  The UISearchDisplayController used to manage the search interface.
  @discussion You can customise it in your subclass to enable scope buttons, etc.
@@ -77,4 +97,17 @@ Forces the fetched results controllers to be recreated, causing performFetch to
  */
 - (void) reloadFetchedResultsControllers;
 
+/**---------------------------------------------------------------------------------------
+ * @name Methods that can overridden in subclass, but defaults are used otherwise.
+ *  ---------------------------------------------------------------------------------------
+ */
+/**
+ *  Returns the section key path string to use when constructing new NSFetchedResultsControllers. nil by default, so without overriding NSFetchedResultsControllers will have no sections. NOTE: if `searchIsActive` is YES then the return value will be ignored and nil used regardless. This is because A a section index should not be shown while searching, and B executed fetch requests take longer when sections are used. When searching this is especially noticable as a new fetch request is executed upon each key stroke during search.
+ *
+ *  @param controller The SJOSearchableFetchedResultsController creating the NSFetchedResultsController for which a sectionKeyPath is needed.
+ *
+ *  @return The sectionKeyPath to use in constructing a NSFetchedResultsController, or nil for no sections.
+ */
+- (NSString *)sectionKeyPathForSearchableFetchedResultsController:(SJOSearchableFetchedResultsController *)controller;
+
 @end

Library/SJOSearchableFetchedResultsController.m

@@ -14,10 +14,21 @@
 @interface SJOSearchableFetchedResultsController ()
 @property (strong, nonatomic) NSFetchedResultsController *fetchedResultsController;
 @property (strong, nonatomic) NSFetchedResultsController *searchFetchedResultsController;
+@property (nonatomic, strong, readwrite) NSManagedObjectContext *managedObjectContext;
+@property(nonatomic, assign, readwrite) BOOL searchIsActive;
 @end
 
 @implementation SJOSearchableFetchedResultsController
 
+// To override the setter the property must be synthesized
+@synthesize store = _store;
+
+- (instancetype)initWithContext:(NSManagedObjectContext *)managedObjectContext style:(UITableViewStyle)style {
+	if ([super initWithStyle:style]) {
+        self.managedObjectContext = managedObjectContext;
+    }
+    return self;
+}
 
 - (void)viewDidLoad
 {
@@ -200,11 +211,29 @@ - (SJODataStore *)store
     }
 }
 
+- (void)setStore:(SJODataStore *)store {
+	_store = store;
+	self.managedObjectContext = store.mainContext;
+}
+
+- (NSString *)sectionKeyPathForSearchableFetchedResultsController:(SJOSearchableFetchedResultsController *)controller {
+	return nil;
+}
+
 - (NSFetchedResultsController *)newFetchedResultsControllerWithSearch:(NSString *)searchString
 {
+	NSString *sectionKeyPath;
+    /**
+     *  Only use a sectionKeyPath when not searching becuase:
+	 *		- A a section index should not be shown while searching, and
+	 *		- B executed fetch requests take longer when sections are used. When searching this is especially noticable as a new fetch request is executed upon each key stroke during search.
+     */
+    if (!self.searchIsActive) {
+        sectionKeyPath = [self sectionKeyPathForSearchableFetchedResultsController:self];
+    }
     NSFetchedResultsController *fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:[self fetchRequestForSearch:searchString]
-                                                                                               managedObjectContext:self.store.mainContext
-                                                                                                 sectionNameKeyPath:nil
+                                                                                               managedObjectContext:self.managedObjectContext
+                                                                                                 sectionNameKeyPath:sectionKeyPath
                                                                                                           cacheName:nil];
     fetchedResultsController.delegate = self;
     NSError *error = nil;
@@ -243,6 +272,7 @@ - (NSFetchedResultsController *)searchFetchedResultsController
 
 - (BOOL)searchBarShouldBeginEditing:(UISearchBar *)searchBar
 {
+	self.searchIsActive = YES;
 	[searchBar sizeToFit];
 	[searchBar setShowsCancelButton:YES animated:YES];
 	return YES;
@@ -257,6 +287,7 @@ - (BOOL)searchBarShouldEndEditing:(UISearchBar *)searchBar
 
 -(void)searchBarSearchButtonClicked:(UISearchBar *)searchBar
 {
+	self.searchIsActive = NO;
     [self searchBarShouldEndEditing:searchBar];
 }